Friday, December 18, 2009
Radiation: cancer risk estimates remain same
The complete report (UNSCEAR 2006) with all Annexes from the United Nations Scientific Committee on the Effects of Atomic Radiation has now been published the first set of Annexes in 2008 and the next set in 2009. Because of resource crunch, UNSCEAR could not publish the report which was ready in 2006. That the Committee did not have funds to publish its report promptly is regrettable. UNSCEAR reports underpin international standards for radiation protection.
Dr K.S.Parthasarathy
Date:17/12/2009 URL: http://www.thehindu.com/thehindu/seta/2009/12/17/stories/2009121750111300.htm
________________________________________
Back Sci Tech
Radiation: cancer risk estimates remain same
Radiation protection specialists can breathe easy due to the overall view of the U.N. Committee on current risk estimates
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in its latest report has reiterated that the current risk estimates for cancer and hereditary effects in humans from irradiation need not be changed, in spite of new findings about non-targeted and delayed cellular effects.
Latest annexures
The October 2009 issue of the Health Physics Journal has summarised the latest annexures which covered “Non targeted and delayed effects of exposure to ionizing radiation,” “Effects of ionizing radiation on the immune system”, and “Source to effects assessment for radon in homes and work places”. UNSCEAR published two other earlier annexures in August 2008.
“Non-targeted and delayed effects occur in cells that were themselves not irradiated. They include genomic changes in the daughters of irradiated cells, changes in non-irradiated cells as a result of signals from irradiated cells (so-called bystander effects), and potential health effects in offspring due to irradiation of the parents,” the Committee clarified in a press release.
Scientists have observed “genomic instability” (effect appearing later in cells formed after several multiplications) and “bystander effects” (effects that manifest in cells not directly affected).
These could not be explained by conventional hypotheses. The International Commission on Radiological Protection (ICRP) did not consider them while estimating radiation risk estimates.
In 2000, I sought the views of Dr Jack Valentin, the Scientific Secretary, ICRP, on the impact of genomic instability on ICRP recommendations.
The argument
The then National Radiological Protection Board (NRPB), U.K., has argued that the estimates of radiation induced cancer risk in humans have been derived directly from epidemiological observations, and are, therefore, independent of the potential contribution from any novel cellular mechanism (Interview in AERB Newsletter 13: 1, 2000)
“At present, I find that unlikely, but it would seem wise to avoid being categorical,” he cautioned. “We must investigate it thoroughly,” he asserted.
UNSCEAR 2006 seems to have settled the issue.
Norman Gentner, Chairman of UNSCEAR conceded that these non-targeted effects may potentially amplify the biological effectiveness of a given radiation dose by increasing the number of cells that experience effects over those directly exposed to the radiation (UNSCEAR Release, 2009)
UNSCEAR noted that any clear relationship between non-targeted effects and observed health effects attributable to radiation remains contentious.
“Risk estimates are based on population health studies, which implicitly incorporate all elements including direct targeted effects of irradiation as well as non-targeted and delayed effects,” the latest UNSCEAR statement, is almost similar to NRPB’s, made nine years ago.
Radiation protection specialists and regulators can breathe easy; the overall view of the Committee is that the currently available risk estimates do not require changes.
UNSCEAR 2006 noted that some recent studies have shown that low levels of radiation can stimulate the immune system, at least for short periods.
Experimental studies
These findings emerge from experimental studies and large scale epidemiological assessments of A-bomb survivors, residents of areas in Russia and the U.S. contaminated by weapons production, Chernobyl emergency workers and residents and patients undergoing radiotherapy. Data from these groups showed common patterns (UNSCEAR release, 2009).
The impact of ionizing radiation may be stronger during foetal development and in some diseases such as HIV AIDS; autoimmune diseases and genetic disorders also compromise the immune system making it more sensitive to irradiation.
The disclosure
UNSCEAR disclosed that there is direct evidence to confirm a small but detectable risk of lung cancer from living with radon in home.
The Committee evaluated recent direct studies of the public in Europe, North America and China exposed to relatively low levels of radon in their dwellings.
Thus far, researchers estimated the risk from radon from health studies of underground miners who were exposed to high levels of radon and its decay products.
United Nations set up UNSCEAR in 1955; its mandate is to report on levels and effects of radiation to the UN General Assembly. Resource crunch delayed the publication of UNSCEAR 2006. It has hopefully been corrected. The work of the Committee is crucial as it underpins international standards for radiation protection.
Raja Ramanna Fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk )
K.S. PARTHASARATHY
© Copyright 2000 - 2009 The Hindu
Dr K.S.Parthasarathy
Date:17/12/2009 URL: http://www.thehindu.com/thehindu/seta/2009/12/17/stories/2009121750111300.htm
________________________________________
Back Sci Tech
Radiation: cancer risk estimates remain same
Radiation protection specialists can breathe easy due to the overall view of the U.N. Committee on current risk estimates
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in its latest report has reiterated that the current risk estimates for cancer and hereditary effects in humans from irradiation need not be changed, in spite of new findings about non-targeted and delayed cellular effects.
Latest annexures
The October 2009 issue of the Health Physics Journal has summarised the latest annexures which covered “Non targeted and delayed effects of exposure to ionizing radiation,” “Effects of ionizing radiation on the immune system”, and “Source to effects assessment for radon in homes and work places”. UNSCEAR published two other earlier annexures in August 2008.
“Non-targeted and delayed effects occur in cells that were themselves not irradiated. They include genomic changes in the daughters of irradiated cells, changes in non-irradiated cells as a result of signals from irradiated cells (so-called bystander effects), and potential health effects in offspring due to irradiation of the parents,” the Committee clarified in a press release.
Scientists have observed “genomic instability” (effect appearing later in cells formed after several multiplications) and “bystander effects” (effects that manifest in cells not directly affected).
These could not be explained by conventional hypotheses. The International Commission on Radiological Protection (ICRP) did not consider them while estimating radiation risk estimates.
In 2000, I sought the views of Dr Jack Valentin, the Scientific Secretary, ICRP, on the impact of genomic instability on ICRP recommendations.
The argument
The then National Radiological Protection Board (NRPB), U.K., has argued that the estimates of radiation induced cancer risk in humans have been derived directly from epidemiological observations, and are, therefore, independent of the potential contribution from any novel cellular mechanism (Interview in AERB Newsletter 13: 1, 2000)
“At present, I find that unlikely, but it would seem wise to avoid being categorical,” he cautioned. “We must investigate it thoroughly,” he asserted.
UNSCEAR 2006 seems to have settled the issue.
Norman Gentner, Chairman of UNSCEAR conceded that these non-targeted effects may potentially amplify the biological effectiveness of a given radiation dose by increasing the number of cells that experience effects over those directly exposed to the radiation (UNSCEAR Release, 2009)
UNSCEAR noted that any clear relationship between non-targeted effects and observed health effects attributable to radiation remains contentious.
“Risk estimates are based on population health studies, which implicitly incorporate all elements including direct targeted effects of irradiation as well as non-targeted and delayed effects,” the latest UNSCEAR statement, is almost similar to NRPB’s, made nine years ago.
Radiation protection specialists and regulators can breathe easy; the overall view of the Committee is that the currently available risk estimates do not require changes.
UNSCEAR 2006 noted that some recent studies have shown that low levels of radiation can stimulate the immune system, at least for short periods.
Experimental studies
These findings emerge from experimental studies and large scale epidemiological assessments of A-bomb survivors, residents of areas in Russia and the U.S. contaminated by weapons production, Chernobyl emergency workers and residents and patients undergoing radiotherapy. Data from these groups showed common patterns (UNSCEAR release, 2009).
The impact of ionizing radiation may be stronger during foetal development and in some diseases such as HIV AIDS; autoimmune diseases and genetic disorders also compromise the immune system making it more sensitive to irradiation.
The disclosure
UNSCEAR disclosed that there is direct evidence to confirm a small but detectable risk of lung cancer from living with radon in home.
The Committee evaluated recent direct studies of the public in Europe, North America and China exposed to relatively low levels of radon in their dwellings.
Thus far, researchers estimated the risk from radon from health studies of underground miners who were exposed to high levels of radon and its decay products.
United Nations set up UNSCEAR in 1955; its mandate is to report on levels and effects of radiation to the UN General Assembly. Resource crunch delayed the publication of UNSCEAR 2006. It has hopefully been corrected. The work of the Committee is crucial as it underpins international standards for radiation protection.
Raja Ramanna Fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk )
K.S. PARTHASARATHY
© Copyright 2000 - 2009 The Hindu
Friday, December 04, 2009
Kaiga incident serves as a wake-up call
Date:03/12/2009 URL: http://www.thehindu.com/thehindu/seta/2009/12/03/stories/2009120350081300.htm
________________________________________
Kaiga incident serves as a wake-up call
Tritium is the least toxic of all radioactive materials, not posing any external hazard but internal hazard if ingested
Treating ingestion: Tritium can be removed faster by drinking more fluids and water. Administering diuretics to the workers is another effective method.
Recently, a bizarre incident at the Kaiga Generating Station received wide media attention. Someone deliberately added some tritiated heavy water into a water cooler at the Kaiga Generating Station causing radiation exposure to 55 workers who drank water from it.
Authorities have characterised it as “sabotage,” “act of mischief,” “malevolent act” etc. Specialists in the appropriate discipline will identify the right term to be used!
Very serious incident
It is a very serious incident. It adds a new dimension to the already existing security and access control procedures. Some procedures need tightening. It is a wake up call.
Media reports reflected heightened perception, concerns and some misunderstanding about the way the Station handled the incident.
Extracts of the reports and the related facts are listed thus:
“Tritium is very difficult to remove from the body.” It is not true. Tritium is another form of hydrogen; like ordinary hydrogen it reacts with oxygen and forms tritiated water. Ninety seven per cent of tritium entering the body remains in soft tissue, will reach equilibrium in 2 hours and will get removed with a typical half period of 6 days, through urine and perspiration.
Three per cent remains for a longer period (about 40 days). The two components are considered in calculating the radiation dose. Tritium’s physical half life of 12.3 years is not relevant.
We can remove tritium faster by drinking more fluids and water. Administering diuretics to the workers is another effective method (diuretics are drugs that help to remove water from body). This has to be done under medical supervision.
Effective dose control
That is why the workers whose intakes exceeded certain limits were sent to the hospital (Such interventions are done for effective dose control over the monitoring period). They were not admitted. They did not fall sick as reported by some newspapers.
Is tritium, a highly radioactive substance? Tritium emits beta particles of very low energy. It does not pose any external radiation hazard; it poses internal hazard if ingested. Tritium is the least toxic of all radioactive materials. But we must control all tritium intakes.
“How is it likely to impact the employees who drank the water?” “Doctors say that even the smallest exposure to radiation will have a long term health impact.”
The impact depends on the dose received by the workers. In the present case, only two workers marginally exceeded the radiation dose limit of 30 mSv prescribed by the Atomic Energy Regulatory Board.
No worker had received contamination from any radionuclide other than tritium.
Even the currently estimated doses will be reduced further as these workers take diurectics under medical guidance. When radiation doses are within, close to or below the limit, the health impact is insignificant. However, the doses to workers must be as low as reasonably achievable. Getting doses close to the limit repeatedly is not acceptable. In such instances the work practices must be evaluated to reduce the dose further.
What happens to people living along the Kali River? Especially downstream, who spend a substantial amount of time standing in water to catch fish and eat it?
The contamination was confined to a single water cooler. Specialists located and isolated it from use. The contamination incident has no environmental impact.
The Annual report of AERB (available at www.aerb.gov.in) gives the data on radioactive releases from all power stations.
The resultant radiation doses are small fractions of the AERB limit and are within the variations in the natural background radiation present everywhere. The Kaiga Generating Station is no exception.
Are there legal provisions against such malevolent acts? Rule 23 of the Atomic Energy (Radiation Protection) Rules, 2004, issued under Section 17 of the Atomic Energy Act 1962 states that “Every worker shall observe the safety requirements and follow safety procedures and instructions and shall refrain from any wilful act that could be detrimental to self, co-workers, the radiation installation and public.”
The penalties
Violation of rules made under Section 17 of the Act shall be punishable with imprisonment for a term which may extend to five years, or with fine, or with both.
Depending on the circumstances, if proved guilty, the accused may be convicted for violating the provisions under Section 10 of The Weapons of Mass Destruction and their Delivery Systems (Prohibition of Unlawful Activities) Act, 2005.
K.S. PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk )
Sunday, November 15, 2009
Dr K.S.Parthasarathy in conversation with Mr.Yuri Vishnevskiy
Dr. K S Parthasarathy, Secretary, Atomic Energy Regulatory Board Interviewed Yuri Vishnevskiy, the then Chairman of Federal Nuclear and Radiation Safety authority of Russia (RF Gosatomnadzor) at Vienna during May 3-7, 1999. Extracts were published in AERB Newsletter
[Reproduced from AERB Newsletter Vol 12, No2, 1999]
[ Mr. Yuri Vishnevskiy is currently the Chairman of Federal Nuclear and Radiation Safety authority of Russia (RF Gosatomnadzor). He graduated from the Tomsk Polytechnic Institute in 1966 and worked in different official capacities (Engineer, Senior Engineer, Deputy Shift Head, Shift Head and Senior Shift Head) of the Syberia Chemical Plant from 1966 to 1988. He was Head of RF Gosatomnadzor Inspection at Balakovo Nuclear Power Plant from 1985-1991. In 1990 he was elected a People's Deputy of the Russian Federation. Mr. Vishnevskiy was appointed Chairman of Federal Nuclear and Radiation Safety Authority of Russia in 1991.
Dr. K.S. Parthasarathy, Secretary, AERB interviewed Mr.Yuri G. Vishnevskiy, Chairman, Gosatomnazdor of Russia. (Gosatomnadzor is the State Safety Regulatory Authority of Russia) at Vienna].
Excerpts:
KSP: Mr Vishnevskiy, I consider it a proud privilege and honour to talk to you on behalf of the readers of AERB Newsletter on the functions and the activities of the State Safety Regulatory Authority in Russia. Your enthusiastic participation at the Peer Review Discussion on 'Assessment of Regulatory Effectiveness' at the International Atomic Energy Agency gave me ample opportunity to observe you closely. Your interventions on several occasions assisted us to focus on key issues in nuclear regulation. Which are the areas of responsibility of Gosatomnadzor?
Mr.Vishnevskiy: Gosatomnadzor was set up in 1991 by a Decree of the President of the Russian Federation. It is the legal successor to Gosatomnadzor of the USSR. It is a federal executive body with responsibility for the state regulation of safety in relation to the use of atomic energy (except for regulation of activities connected with the development, production, testing, maintenance, storage, and decommissioning of nuclear weapons and also with the development, production and maintenance of military nuclear power installations. The aim of the agency is to establish a situation where the staff of the nuclear facilities, the population at large and the environment are protected from undue radiation risks and where uncontrolled distribution of nuclear material is excluded.
KSP: So the Gosatomnadzor has a wide spectrum of responsibilities.
We issue licenses to various users of atomic energy after ensuring that safety requirements are met. My agency organises and implements the superiision of the production and use of atomic energy, of handling of nuclear materials, radioactive substances and radioactive waste. We carry out the supervision for non-proliferation of nuclear technology and nuclear materials, physical protection of nuclear materials, nuclear installations, radioactive sources, storage facilities for nuclear materials, radioactive substances and radioactive waste as well as the control of the observance by the Russian Federation of international and other agreements in force. We organise scientific research to substantiate the principles and criteria, the standards and rules for safe usage of atomic energy. We have responsibility
to inform the public and the state authorities about the safety status of nuclear installations, radiation sources and storage facilities. The Regulatory Agency operates from its Headquarters, Interregional Offices, Interregional Department for Information Gathering and Information Security as well as the Scientific & Engineering Centre for Nuclear and Radiation Safety. The interregional offices are located in seven regions and the Headquarters is in Moscow.
KSP : Administratively to whom do you report?
Mr.Vishnevskiy : We report to the President of Russian Federation. My reports and observations are sent to the Government. I shall send my remarks and points of view to the ministry if my directives are not complied with. Parliament helps me to speed up the Bills.
KSP : In the Peer Discussions, one of the issues which was discussed at length was the independence of the regulatory agency. The need to develop core competence in house was highlighted. While a great degree of independence can be achieved by incorporating appropriate legislation, there is no easy way to develop independent core competence in a short period of time. Since financial resources are limited, it is essential to avoid unnecessary duplication of research efforts. Fortunately in India we have the support of Bhabha Atomic Research Centre - a centre of excellence. ln fact many of us in AERB, spent several decades in BARC before joining AERB. What is your experience in Russia? Where do you get the technical and scienfific support from?
Mr.Vishnevskiy : Probably our situation is a bit easier. Though our first nuclear power reactor was commissioned in 1954, the regulatory organisation was set up only in 1984. We have several research institutes such as the Kurchatov Institute, the Academy of Sciences and Institute of Minnatom. Besides these, we have our own Scienfific and Engineering Centre for Nuclear and Radiation Safety (SEC NRS). As a matter of fact, at any time, there is some sort of competition between these institutions. We use this carefuly and effectively. We assign a task to one institution and request another institution to review their results. The SEC NRS co-ordinates all research efforts. Occasionally we send some projects to the Academy of Sciences.
KSP : Do you pay these institutions?
Mr.Vishnevskiy: (Smiles) Oh! Payments! all payments are made by the applicant. The Scienfific and Engineering Centre (SEC NRS) can hire any specialist. For adequate accomplishing the varriety of the problems the experts from other organizations are invited on the contract basis. SEC NRS renders the engineering and scientific support to the RF Gosatomnadzor; the research conducted by SEC NRS is the scientific ground for all other activities to support the Gosatomnadzor of Russia. The R&D works are directed to verify or validate the criteria and principles of nuclear and radiation safety used in the regulatory documents and for expertise. The SEC NRS carries out safety assessments of nuclear installations, radiation sources and storage facilities; participates in establishing the legislative basis in the field of the use of nuclear energy, nuclear materials, radioactive substances and radioactive waste management, as well as in the works aimed .at providing the legislative basis for nuclear and radiation safety regulation (except for sanitary and hygienic standards and rules).
KSP: In India, the Regulatory Board assisted the Government in drafting the Factory Rules as applicable to nuclear facilities and installations and administers them in those installations and facilities. During the discussions with other participants who attended the Peer discussions at the International Atomic Energy Agency I found that this practice is unique to India. What are the other responsibilities of SEC?
Mr.Vishnevskiy : 'Child as it was', SEC NRS was involved in nuclear safety issues only. Now, the terms of activity include all peaceful nuclear power facilities. SEC NRS conducts scienfific research to substantiate the principles and criteria for nuclear and radiation safety. The Centre verifies and validates computer codes, generates the concepts of and makes necessary entries into the data bases for safety assessment of nuclear installations, for radioactive substances and radioactive waste. The Concept of the State Control and Accounting for Nuclear Materials, approved by the Government of the Russian Federation, has been worked out with participation of SEC NRS.
Besides, SEC NRS conducts training of the staff, organizes workshops, seminars and
conferences, prepares for publication of various kinds of information materials and documentation authorized by the Gosatomnadzor of Russia.
KSP : Is the Regulatory Authority responsible for the safe application of radiation in the medical field?
Mr.Vishnevskiy : We do not consider how radiation is used by doctors. This is done by the Ministry of Health. But we issue licenses to use radiation equipment. We control the storage and transport of radioactive substances.
KSP : The Atomic Energy Act in India was adopted in the Indian Parliament in 1948. It was primarily meant to preserve natural resources or atomic minerals. In fact, radiation safety or nuclear safety requirements are not even referred to in the Act. This Act was repealed and replaced by the Atomic Energy Act 1962. A few Sections in the Act refer to safety requirements. Several rules under the Act have been promulgated over the years. How was the evolution of Atomic Energy Law in Russia?
Mr.Vishnevskiy : The Regulatory Board in the erstwhile USSR was set up in 1984. Then there was no Law as such. In the early years, there were some Decrees and Ordinances from the Party and Government. Gosatomnadzor was set up by a decree of the President of the Russian Federation in 1991. The competence, rights, duties and responsibilities of Gosatomnadzor and its officials are determined by the Provisions on Gosatomnozdor, approved by the President of the Russian Federation in 1992 and amended in 1993 and 1995.
KSP : What were the reasons for setting up the regulatory agency? Was it in the light of international developments?
Mr.Vishnevskiy : As far as I can recollect, there was no such reason. I am not able to indicate any specific reason for the development. After the accident at Chernobyl nuclear power station, we obtained more powers! Power to use sanctions, for instance. Chernobyl accident turned out to be a blessing in disguise!
KSP : But that was too expensive a way to secure regulatory power! I thought that everyone knew that nuclear technology at its current level of technology is an unforgiving technology.
Mr.Vishnevskiy : Not really. Probably more important than the regulatory agency getting more powers is that the accident brought about important changes in the minds of those who operate the reactors. Greater awareness in the operator.
KSP : What was the strength of the regulatory agency prior to the accident?
Mr.Vishnevskiy : Much less than now. Currently, the strength of Gosatomnadzer is 1000 plus; four to five fold increase since Chernobyl accident. Prior to the accident, there was no realisation that regulatory principles should be implemented fully in all nuclear power plants.
KSP: You mean that prior to the accident, regulatory principles were not formaly implemented in the nuclear power plants in Russia.
Mr.Vishnevskiy : I think, you can say so. Now our regulatory responsibility covers all stages of the nuclear fuel cycle, including mining, fuel fabrication, reactor operation, reprocessing and waste management.
KSP : For the regulator to be effective, he should be as competent and knowledgeable, preferably more competent and knowledgeable than those who operate the reactor. How do you achieve this? Do you offer any training to your staff?
Mr.Vishnevskiy : Yes, we have our training centre for training regulatory personnel.
KSP : Do you recruit young people to the regulatory agency?
Mr.Vishnevskiy : As a matter of fact, no new comer joins the regulatory agency. We recruit people of average age with experience in industry
KSP : What is the incentive for experienced people to join the regulatory board?
Mr.Vishnevskiy : There are different reasons. Stable job, stable government job. They have some advantages after retirement. A lot of people joined because of their interest. For instance, I myself came; my deputy joined. In principle we could have setfled down in reactor operation. But we concluded that we can improve safety. Nuclear power has future only if we reach a certain level of safety.
KSP: Mr Vishnevskiy, you have rich and varied expertise and experience and you are currently occupying the chair of the top regulator in the Russian Federation. Can you tell us about any unique and memorable era in your career?
Mr.Vishnevskiy : Unique and memorable era! I was a Member of Parliament for some rime. I made speeches to my electorate! Then the situation was different. That was way back in 1990. 1 was elected from the region in which I was staying then. I was then serving the government.
KSP : Can government officials contest elections?
Mr.Vishnevskiy: Government staff could contest elections then. Now there is a law against it. In 1993, 1 resigned as an M.P.
KSP : You must have enjoyed a high level ,of popularity?
Mr.Vishnevskiy : It was unique. I also learnt that life is not a bed of roses.
KSP : One of the important functions of any regulatory authority is to inspect the installations to ensure compliance with safety requirements. How is inspection of nuclear installation carried out in the Russian Federation?
Mr.Vishnevskiy : We have the system of resident inspectors at the NPP sites. We post the group of five inspectors per site, one Chief Inspector and four inspectors. They belong to different disciplines: radiological safety, lnstrumentation and Control, etc.
In the regulatory authority, the licensing and inspection sections are kept separately. We assign inspection work to specialists, they visit the utility and make recommendations.
KSP : How did you enter the regulatory field?
Mr.Vishnevskiy : I attended a special technical course in technical institute which has special faculty working in the nuclear and engineering physics. I have graduated with specialisafion in management of Nuclear Power Plants. In 1966, 1 graduated in engineering and physics and joined a nuclear power plant. In 1985, 1 entered the regulatory field.
KSP : Whenever the issue of public awareness come up for discussion in the Peer Review meeting, you argued passionately in favour of various public information programmes. What is the role of Gosatomnadzor in the area?
Mr.Vishnevskiy : We keep contact with mass media, hold meetings in which representatives of the regulatory authority meet public organisarion, information agencies and private persons. In order to coordinate these activities we established the Interregional Territorial Department of Information gathering and Information Protection as a Public Relations Division. Summarised information on the nuclear and radiation safety status in the country is sent monthly to the main information agencies in Russia. The information is transmitted to the electronic mass media regularly. In case of an emergency they will receive updated 'fresh' information.
KSP : AERB publishes its annual report. We publicise the regulatory restrictions placed on nuclear installations. The fact that AERB - a government agency - can place restrictions on government nuclear installations appears to improve the credibility of the Organisation. The restrictions include reducing power levels of nuclear power plants, delicensing of crew and occasionally shutting down installations. What do you do to improve the credibility of your organisaflon? Have you taken any special steps?
Mr.Vishnevskiy : In Russia nuclear power plants are in the government sector. Nuclear industries (industries producing nuclear components and system) might also be the private enterprises. The credibility question can be easily solved. My prescription is: don't tell a lie, be honest, open and transparent. I invite Green Peace. I discuss safety issues with them. I get a lot of material from their placards and transparencies. Many such information, I receive, I may not get from normal government channels.
KSP : Where were you when the accident occurred at the Chernobyl Nuclear Power Station?
Mr.Vishnevskiy : I was the then Chief Inspector at the Balakovo Nuclear Power Station. We were just finishing the tests to start up the reactor.
KSP : How did the people react?
Mr.Vishnevskiy : Nobody could understand that such an accident can happen. We spend time investigating the possibility of such accidents in VVER, the Russian version of the Pressurised Water Reactor
KSP : Chernobyl power reactors had known deficiencies.
Mr.Vishnevskiy: Frankly speaking, there were some observations on the weaknesses of Chernobyl reactors. But nobody could foresee that
the deficiencies could lead to such a reactor accident. To create such accidents, many events were to be postulated or imagined.
KSP : How was the attitude of the staff?
Mr.Vishnevskiy : Before the accident, the attitude of the management towards the nuclear power reactor was the some as towards a conventional power station. The only difference was that they know that one is 'a nuclear boiler' and the other 'a conventional boiler'. But after the accident of Chernobyl Nuclear Power Station, there was clear change in the attitude. They started respecting the process of nuclear reactions.
KSP : What were the criteria followed to evacuate the population from the contaminated zone around the reactor?
Mr.Vishnevskiy : After the accident specific measures were taken. We measured the radioactivity levels at different areas and divided them into different zones depending on the radioactivity levels. On this basis, we decided from which zone people will have to be removed. We decided that people should be evacuated from all the zones in which they are likely to be exposed to more than 35 Bert in 70 years. (Bert was mentioned as the Unit it appears to be equal to rem).
KSP : Did the staff of nuclear power stations leave in large numbers?
Mr.Vishnevskiy : Some people left. Others did not.
KSP : Has the accident affected the morale of the staff?
Mr.Vishnevskiy : No, it did not. Certainly it did influence some people coming to the faculty of nuclear science. Now we have fully recovered. Now there is competition among people!
KSP : If you have the option, would you advise your son to join the nuclear field?
Mr.Vishnevskiy : My son is in the nuclear field! Earlier he worked in a nuclear power station. Now he is member of staff of Scientific and Engineering Centre for Nuclear and Radiation Safety.
KSP : What is the future of nuclear power in the world? There is a move against nuclear power in several European countries.
Mr.Vishnevskiy . It is a challenging question! Nuclear power contributes substantially to the total power generated. I don't think we can eliminate nuclear power completely.
KSP : What is the future of fusion power?
Mr.Vishnevskiy : It is difficult to say. Even if fusion power becomes reliable, the cost is likely to be high. I think it may take 10 - 20 years of further technological development.
KSP : India has consciously planned to set up a three stage nuclear power programme. Our ultimate goal is to make use of the vast resources of thorium available in the country as our uranium resources are modest. How is the programme envisaged in the Russian Federation?
Mr.Vishnevskiy: We have established the thermal reactor technology. We have reactors of advanced design under planning stage. We have considerable interest in breeder reactors. There are economic issues, fast reactor fuel is costlier. Currently, our breeder programme is at stand still. We have to continue R&D in this area to develop newer concepts. We are carrying out work in the liquid metal cooling system.
KSP : It is known that Pressurized Water Reactors become popular because lot of development work has gone into them while nuclear submarines were constructed. What was the background in the development of RBMK reactors?
Mr.Vishnevskiy : Such reactors were primarily used to produce plutonium.
KSP : It is reported that Chernobyl nuclear power station had performed extremely well and had achieved record levels of power production. Was it one of the reasons for complacency? Was it one of the factors which led to the nuclear disaster?
Mr.Vishnevskiy : Chernobyl power station performed well. Today we may say that complacency was one of the reasons for the disaster. The operators were known to be skilled specialists. Production of power was their main goal.
KSP : You have spent the earlier part of your career as a nuclear operator. Now you are Chief of the Regulatory Organisation. There was on going debate on the various factors that led to the accident at Chernobyl Nuclear Power Station. The designers blamed the operators and the operators blamed the designers. Recently a physicist from Russia's Kurchatov Institute disputed the official version. An interview with him appeared in the January issue of Nuclear Engineering International. What is currently the official position?
Mr.Vishnevskiy : Right in April, the Russian Academy of Earth Sciences published another reason. According to them, there was a localized earthquake close to Unit 4, the bottom structure of the unit developed a crack. There are different versions. Therefore, I cannot comment finally. Now we are closely reviewing all opinions.
KSP : How did the Laws relate to Atomic Energy develop in Russia?
Mr.Vishnevskiy : The Federal Law on the Use of Atomic Energy was issued in 1995.
This was followed by the Federal Law on Radiation Protection of Population in 1996. Earlier the practice used to be to issue Decrees or Ordinances. When I was a member of Russian Supreme Soviet, I took part in the drafting of the Low.
KSP: The regulatory mechanism in India evolved gradually. Till 1983, the regulatory work was carried out in house. The regulatory procedures and the mechanisms established have been the subject of review of high level committees of specialists. These have evolved and were strengthened as per national requirements. How was it done in Russian Federation. Is there any peer review of the regulatory agency?
Mr.Vishnevskiy : No, we do not have formal peer review of the activities of the regulatory agency. We function very carefully. We are able to show that we act as per the international requirements.
KSP : One of the most important areas of activities in the nuclear field is the management of radioactive wastes. What is the role of the Russian regulatory agency in the area?
Mr.Vishnevskiy : Our main role is in the development of scientifically well supported and justified criteria. Our role is that of an initiator. For example, before the establishment of the regulatory board, radioactive wastes were put underground. Today we do not provide a licence for it. We prohibit such a procedure. We require additional justification for the safety of such a method.
Actually, waste management is a common job. Regulatory agency work with the utility and the government will support the programme. Today we have started a programme to manage radioactive wastes.
KSP : Decommissioning of nuclear submarines is reported to be another important area. How big is the issue? What is the responsibility of regulatory agency in the area?
Mr.Vishnevskiy : Speaking precisely, we just started supervising the programme. This activity is with the Defence Department right now. Department of Defence is transferring the responsibility to Department of Atomic Energy. Then the programme will come under the supervision of the regulatory body. Currently we are developing the conceptual approaches ourselves. Decommissioning unused nuclear submarines is an important safety issue.
KSP : Exhaustive and dedicated review of certain areas is one of the ongoing activities of the Atomic Energy Regulatory Board. Thirteen such reviews have been completed So for. Some of these are identical to the IAEA Operational Safety Review Team Mission. Do you organise such programmes.
Mr.Vishnevskiy : We do conduct reviews of certain topics such as strength of containment matters connected with the new design of breeder reactors, Design of VVER for India among others.
KSP : Thank you very much Mr. Vishnevskiy. I am very grateful to you for sparing your time to convey your views on very wide ranging subjects.
[Reproduced from AERB Newsletter Vol 12, No2, 1999]
[ Mr. Yuri Vishnevskiy is currently the Chairman of Federal Nuclear and Radiation Safety authority of Russia (RF Gosatomnadzor). He graduated from the Tomsk Polytechnic Institute in 1966 and worked in different official capacities (Engineer, Senior Engineer, Deputy Shift Head, Shift Head and Senior Shift Head) of the Syberia Chemical Plant from 1966 to 1988. He was Head of RF Gosatomnadzor Inspection at Balakovo Nuclear Power Plant from 1985-1991. In 1990 he was elected a People's Deputy of the Russian Federation. Mr. Vishnevskiy was appointed Chairman of Federal Nuclear and Radiation Safety Authority of Russia in 1991.
Dr. K.S. Parthasarathy, Secretary, AERB interviewed Mr.Yuri G. Vishnevskiy, Chairman, Gosatomnazdor of Russia. (Gosatomnadzor is the State Safety Regulatory Authority of Russia) at Vienna].
Excerpts:
KSP: Mr Vishnevskiy, I consider it a proud privilege and honour to talk to you on behalf of the readers of AERB Newsletter on the functions and the activities of the State Safety Regulatory Authority in Russia. Your enthusiastic participation at the Peer Review Discussion on 'Assessment of Regulatory Effectiveness' at the International Atomic Energy Agency gave me ample opportunity to observe you closely. Your interventions on several occasions assisted us to focus on key issues in nuclear regulation. Which are the areas of responsibility of Gosatomnadzor?
Mr.Vishnevskiy: Gosatomnadzor was set up in 1991 by a Decree of the President of the Russian Federation. It is the legal successor to Gosatomnadzor of the USSR. It is a federal executive body with responsibility for the state regulation of safety in relation to the use of atomic energy (except for regulation of activities connected with the development, production, testing, maintenance, storage, and decommissioning of nuclear weapons and also with the development, production and maintenance of military nuclear power installations. The aim of the agency is to establish a situation where the staff of the nuclear facilities, the population at large and the environment are protected from undue radiation risks and where uncontrolled distribution of nuclear material is excluded.
KSP: So the Gosatomnadzor has a wide spectrum of responsibilities.
We issue licenses to various users of atomic energy after ensuring that safety requirements are met. My agency organises and implements the superiision of the production and use of atomic energy, of handling of nuclear materials, radioactive substances and radioactive waste. We carry out the supervision for non-proliferation of nuclear technology and nuclear materials, physical protection of nuclear materials, nuclear installations, radioactive sources, storage facilities for nuclear materials, radioactive substances and radioactive waste as well as the control of the observance by the Russian Federation of international and other agreements in force. We organise scientific research to substantiate the principles and criteria, the standards and rules for safe usage of atomic energy. We have responsibility
to inform the public and the state authorities about the safety status of nuclear installations, radiation sources and storage facilities. The Regulatory Agency operates from its Headquarters, Interregional Offices, Interregional Department for Information Gathering and Information Security as well as the Scientific & Engineering Centre for Nuclear and Radiation Safety. The interregional offices are located in seven regions and the Headquarters is in Moscow.
KSP : Administratively to whom do you report?
Mr.Vishnevskiy : We report to the President of Russian Federation. My reports and observations are sent to the Government. I shall send my remarks and points of view to the ministry if my directives are not complied with. Parliament helps me to speed up the Bills.
KSP : In the Peer Discussions, one of the issues which was discussed at length was the independence of the regulatory agency. The need to develop core competence in house was highlighted. While a great degree of independence can be achieved by incorporating appropriate legislation, there is no easy way to develop independent core competence in a short period of time. Since financial resources are limited, it is essential to avoid unnecessary duplication of research efforts. Fortunately in India we have the support of Bhabha Atomic Research Centre - a centre of excellence. ln fact many of us in AERB, spent several decades in BARC before joining AERB. What is your experience in Russia? Where do you get the technical and scienfific support from?
Mr.Vishnevskiy : Probably our situation is a bit easier. Though our first nuclear power reactor was commissioned in 1954, the regulatory organisation was set up only in 1984. We have several research institutes such as the Kurchatov Institute, the Academy of Sciences and Institute of Minnatom. Besides these, we have our own Scienfific and Engineering Centre for Nuclear and Radiation Safety (SEC NRS). As a matter of fact, at any time, there is some sort of competition between these institutions. We use this carefuly and effectively. We assign a task to one institution and request another institution to review their results. The SEC NRS co-ordinates all research efforts. Occasionally we send some projects to the Academy of Sciences.
KSP : Do you pay these institutions?
Mr.Vishnevskiy: (Smiles) Oh! Payments! all payments are made by the applicant. The Scienfific and Engineering Centre (SEC NRS) can hire any specialist. For adequate accomplishing the varriety of the problems the experts from other organizations are invited on the contract basis. SEC NRS renders the engineering and scientific support to the RF Gosatomnadzor; the research conducted by SEC NRS is the scientific ground for all other activities to support the Gosatomnadzor of Russia. The R&D works are directed to verify or validate the criteria and principles of nuclear and radiation safety used in the regulatory documents and for expertise. The SEC NRS carries out safety assessments of nuclear installations, radiation sources and storage facilities; participates in establishing the legislative basis in the field of the use of nuclear energy, nuclear materials, radioactive substances and radioactive waste management, as well as in the works aimed .at providing the legislative basis for nuclear and radiation safety regulation (except for sanitary and hygienic standards and rules).
KSP: In India, the Regulatory Board assisted the Government in drafting the Factory Rules as applicable to nuclear facilities and installations and administers them in those installations and facilities. During the discussions with other participants who attended the Peer discussions at the International Atomic Energy Agency I found that this practice is unique to India. What are the other responsibilities of SEC?
Mr.Vishnevskiy : 'Child as it was', SEC NRS was involved in nuclear safety issues only. Now, the terms of activity include all peaceful nuclear power facilities. SEC NRS conducts scienfific research to substantiate the principles and criteria for nuclear and radiation safety. The Centre verifies and validates computer codes, generates the concepts of and makes necessary entries into the data bases for safety assessment of nuclear installations, for radioactive substances and radioactive waste. The Concept of the State Control and Accounting for Nuclear Materials, approved by the Government of the Russian Federation, has been worked out with participation of SEC NRS.
Besides, SEC NRS conducts training of the staff, organizes workshops, seminars and
conferences, prepares for publication of various kinds of information materials and documentation authorized by the Gosatomnadzor of Russia.
KSP : Is the Regulatory Authority responsible for the safe application of radiation in the medical field?
Mr.Vishnevskiy : We do not consider how radiation is used by doctors. This is done by the Ministry of Health. But we issue licenses to use radiation equipment. We control the storage and transport of radioactive substances.
KSP : The Atomic Energy Act in India was adopted in the Indian Parliament in 1948. It was primarily meant to preserve natural resources or atomic minerals. In fact, radiation safety or nuclear safety requirements are not even referred to in the Act. This Act was repealed and replaced by the Atomic Energy Act 1962. A few Sections in the Act refer to safety requirements. Several rules under the Act have been promulgated over the years. How was the evolution of Atomic Energy Law in Russia?
Mr.Vishnevskiy : The Regulatory Board in the erstwhile USSR was set up in 1984. Then there was no Law as such. In the early years, there were some Decrees and Ordinances from the Party and Government. Gosatomnadzor was set up by a decree of the President of the Russian Federation in 1991. The competence, rights, duties and responsibilities of Gosatomnadzor and its officials are determined by the Provisions on Gosatomnozdor, approved by the President of the Russian Federation in 1992 and amended in 1993 and 1995.
KSP : What were the reasons for setting up the regulatory agency? Was it in the light of international developments?
Mr.Vishnevskiy : As far as I can recollect, there was no such reason. I am not able to indicate any specific reason for the development. After the accident at Chernobyl nuclear power station, we obtained more powers! Power to use sanctions, for instance. Chernobyl accident turned out to be a blessing in disguise!
KSP : But that was too expensive a way to secure regulatory power! I thought that everyone knew that nuclear technology at its current level of technology is an unforgiving technology.
Mr.Vishnevskiy : Not really. Probably more important than the regulatory agency getting more powers is that the accident brought about important changes in the minds of those who operate the reactors. Greater awareness in the operator.
KSP : What was the strength of the regulatory agency prior to the accident?
Mr.Vishnevskiy : Much less than now. Currently, the strength of Gosatomnadzer is 1000 plus; four to five fold increase since Chernobyl accident. Prior to the accident, there was no realisation that regulatory principles should be implemented fully in all nuclear power plants.
KSP: You mean that prior to the accident, regulatory principles were not formaly implemented in the nuclear power plants in Russia.
Mr.Vishnevskiy : I think, you can say so. Now our regulatory responsibility covers all stages of the nuclear fuel cycle, including mining, fuel fabrication, reactor operation, reprocessing and waste management.
KSP : For the regulator to be effective, he should be as competent and knowledgeable, preferably more competent and knowledgeable than those who operate the reactor. How do you achieve this? Do you offer any training to your staff?
Mr.Vishnevskiy : Yes, we have our training centre for training regulatory personnel.
KSP : Do you recruit young people to the regulatory agency?
Mr.Vishnevskiy : As a matter of fact, no new comer joins the regulatory agency. We recruit people of average age with experience in industry
KSP : What is the incentive for experienced people to join the regulatory board?
Mr.Vishnevskiy : There are different reasons. Stable job, stable government job. They have some advantages after retirement. A lot of people joined because of their interest. For instance, I myself came; my deputy joined. In principle we could have setfled down in reactor operation. But we concluded that we can improve safety. Nuclear power has future only if we reach a certain level of safety.
KSP: Mr Vishnevskiy, you have rich and varied expertise and experience and you are currently occupying the chair of the top regulator in the Russian Federation. Can you tell us about any unique and memorable era in your career?
Mr.Vishnevskiy : Unique and memorable era! I was a Member of Parliament for some rime. I made speeches to my electorate! Then the situation was different. That was way back in 1990. 1 was elected from the region in which I was staying then. I was then serving the government.
KSP : Can government officials contest elections?
Mr.Vishnevskiy: Government staff could contest elections then. Now there is a law against it. In 1993, 1 resigned as an M.P.
KSP : You must have enjoyed a high level ,of popularity?
Mr.Vishnevskiy : It was unique. I also learnt that life is not a bed of roses.
KSP : One of the important functions of any regulatory authority is to inspect the installations to ensure compliance with safety requirements. How is inspection of nuclear installation carried out in the Russian Federation?
Mr.Vishnevskiy : We have the system of resident inspectors at the NPP sites. We post the group of five inspectors per site, one Chief Inspector and four inspectors. They belong to different disciplines: radiological safety, lnstrumentation and Control, etc.
In the regulatory authority, the licensing and inspection sections are kept separately. We assign inspection work to specialists, they visit the utility and make recommendations.
KSP : How did you enter the regulatory field?
Mr.Vishnevskiy : I attended a special technical course in technical institute which has special faculty working in the nuclear and engineering physics. I have graduated with specialisafion in management of Nuclear Power Plants. In 1966, 1 graduated in engineering and physics and joined a nuclear power plant. In 1985, 1 entered the regulatory field.
KSP : Whenever the issue of public awareness come up for discussion in the Peer Review meeting, you argued passionately in favour of various public information programmes. What is the role of Gosatomnadzor in the area?
Mr.Vishnevskiy : We keep contact with mass media, hold meetings in which representatives of the regulatory authority meet public organisarion, information agencies and private persons. In order to coordinate these activities we established the Interregional Territorial Department of Information gathering and Information Protection as a Public Relations Division. Summarised information on the nuclear and radiation safety status in the country is sent monthly to the main information agencies in Russia. The information is transmitted to the electronic mass media regularly. In case of an emergency they will receive updated 'fresh' information.
KSP : AERB publishes its annual report. We publicise the regulatory restrictions placed on nuclear installations. The fact that AERB - a government agency - can place restrictions on government nuclear installations appears to improve the credibility of the Organisation. The restrictions include reducing power levels of nuclear power plants, delicensing of crew and occasionally shutting down installations. What do you do to improve the credibility of your organisaflon? Have you taken any special steps?
Mr.Vishnevskiy : In Russia nuclear power plants are in the government sector. Nuclear industries (industries producing nuclear components and system) might also be the private enterprises. The credibility question can be easily solved. My prescription is: don't tell a lie, be honest, open and transparent. I invite Green Peace. I discuss safety issues with them. I get a lot of material from their placards and transparencies. Many such information, I receive, I may not get from normal government channels.
KSP : Where were you when the accident occurred at the Chernobyl Nuclear Power Station?
Mr.Vishnevskiy : I was the then Chief Inspector at the Balakovo Nuclear Power Station. We were just finishing the tests to start up the reactor.
KSP : How did the people react?
Mr.Vishnevskiy : Nobody could understand that such an accident can happen. We spend time investigating the possibility of such accidents in VVER, the Russian version of the Pressurised Water Reactor
KSP : Chernobyl power reactors had known deficiencies.
Mr.Vishnevskiy: Frankly speaking, there were some observations on the weaknesses of Chernobyl reactors. But nobody could foresee that
the deficiencies could lead to such a reactor accident. To create such accidents, many events were to be postulated or imagined.
KSP : How was the attitude of the staff?
Mr.Vishnevskiy : Before the accident, the attitude of the management towards the nuclear power reactor was the some as towards a conventional power station. The only difference was that they know that one is 'a nuclear boiler' and the other 'a conventional boiler'. But after the accident of Chernobyl Nuclear Power Station, there was clear change in the attitude. They started respecting the process of nuclear reactions.
KSP : What were the criteria followed to evacuate the population from the contaminated zone around the reactor?
Mr.Vishnevskiy : After the accident specific measures were taken. We measured the radioactivity levels at different areas and divided them into different zones depending on the radioactivity levels. On this basis, we decided from which zone people will have to be removed. We decided that people should be evacuated from all the zones in which they are likely to be exposed to more than 35 Bert in 70 years. (Bert was mentioned as the Unit it appears to be equal to rem).
KSP : Did the staff of nuclear power stations leave in large numbers?
Mr.Vishnevskiy : Some people left. Others did not.
KSP : Has the accident affected the morale of the staff?
Mr.Vishnevskiy : No, it did not. Certainly it did influence some people coming to the faculty of nuclear science. Now we have fully recovered. Now there is competition among people!
KSP : If you have the option, would you advise your son to join the nuclear field?
Mr.Vishnevskiy : My son is in the nuclear field! Earlier he worked in a nuclear power station. Now he is member of staff of Scientific and Engineering Centre for Nuclear and Radiation Safety.
KSP : What is the future of nuclear power in the world? There is a move against nuclear power in several European countries.
Mr.Vishnevskiy . It is a challenging question! Nuclear power contributes substantially to the total power generated. I don't think we can eliminate nuclear power completely.
KSP : What is the future of fusion power?
Mr.Vishnevskiy : It is difficult to say. Even if fusion power becomes reliable, the cost is likely to be high. I think it may take 10 - 20 years of further technological development.
KSP : India has consciously planned to set up a three stage nuclear power programme. Our ultimate goal is to make use of the vast resources of thorium available in the country as our uranium resources are modest. How is the programme envisaged in the Russian Federation?
Mr.Vishnevskiy: We have established the thermal reactor technology. We have reactors of advanced design under planning stage. We have considerable interest in breeder reactors. There are economic issues, fast reactor fuel is costlier. Currently, our breeder programme is at stand still. We have to continue R&D in this area to develop newer concepts. We are carrying out work in the liquid metal cooling system.
KSP : It is known that Pressurized Water Reactors become popular because lot of development work has gone into them while nuclear submarines were constructed. What was the background in the development of RBMK reactors?
Mr.Vishnevskiy : Such reactors were primarily used to produce plutonium.
KSP : It is reported that Chernobyl nuclear power station had performed extremely well and had achieved record levels of power production. Was it one of the reasons for complacency? Was it one of the factors which led to the nuclear disaster?
Mr.Vishnevskiy : Chernobyl power station performed well. Today we may say that complacency was one of the reasons for the disaster. The operators were known to be skilled specialists. Production of power was their main goal.
KSP : You have spent the earlier part of your career as a nuclear operator. Now you are Chief of the Regulatory Organisation. There was on going debate on the various factors that led to the accident at Chernobyl Nuclear Power Station. The designers blamed the operators and the operators blamed the designers. Recently a physicist from Russia's Kurchatov Institute disputed the official version. An interview with him appeared in the January issue of Nuclear Engineering International. What is currently the official position?
Mr.Vishnevskiy : Right in April, the Russian Academy of Earth Sciences published another reason. According to them, there was a localized earthquake close to Unit 4, the bottom structure of the unit developed a crack. There are different versions. Therefore, I cannot comment finally. Now we are closely reviewing all opinions.
KSP : How did the Laws relate to Atomic Energy develop in Russia?
Mr.Vishnevskiy : The Federal Law on the Use of Atomic Energy was issued in 1995.
This was followed by the Federal Law on Radiation Protection of Population in 1996. Earlier the practice used to be to issue Decrees or Ordinances. When I was a member of Russian Supreme Soviet, I took part in the drafting of the Low.
KSP: The regulatory mechanism in India evolved gradually. Till 1983, the regulatory work was carried out in house. The regulatory procedures and the mechanisms established have been the subject of review of high level committees of specialists. These have evolved and were strengthened as per national requirements. How was it done in Russian Federation. Is there any peer review of the regulatory agency?
Mr.Vishnevskiy : No, we do not have formal peer review of the activities of the regulatory agency. We function very carefully. We are able to show that we act as per the international requirements.
KSP : One of the most important areas of activities in the nuclear field is the management of radioactive wastes. What is the role of the Russian regulatory agency in the area?
Mr.Vishnevskiy : Our main role is in the development of scientifically well supported and justified criteria. Our role is that of an initiator. For example, before the establishment of the regulatory board, radioactive wastes were put underground. Today we do not provide a licence for it. We prohibit such a procedure. We require additional justification for the safety of such a method.
Actually, waste management is a common job. Regulatory agency work with the utility and the government will support the programme. Today we have started a programme to manage radioactive wastes.
KSP : Decommissioning of nuclear submarines is reported to be another important area. How big is the issue? What is the responsibility of regulatory agency in the area?
Mr.Vishnevskiy : Speaking precisely, we just started supervising the programme. This activity is with the Defence Department right now. Department of Defence is transferring the responsibility to Department of Atomic Energy. Then the programme will come under the supervision of the regulatory body. Currently we are developing the conceptual approaches ourselves. Decommissioning unused nuclear submarines is an important safety issue.
KSP : Exhaustive and dedicated review of certain areas is one of the ongoing activities of the Atomic Energy Regulatory Board. Thirteen such reviews have been completed So for. Some of these are identical to the IAEA Operational Safety Review Team Mission. Do you organise such programmes.
Mr.Vishnevskiy : We do conduct reviews of certain topics such as strength of containment matters connected with the new design of breeder reactors, Design of VVER for India among others.
KSP : Thank you very much Mr. Vishnevskiy. I am very grateful to you for sparing your time to convey your views on very wide ranging subjects.
Technologies to harvest uranium from sea
India has made modest progress in extracting uranium from sea water. The quantity still remains in milligrammes. There are plans to "scale up" the facilities
K.S.Parthasarathy
Date:12/11/2009 URL: http://www.thehindu.com/thehindu/seta/2009/11/12/stories/2009111250321300.htm
________________________________________
Back Sci Tech
Technologies to harvest uranium from sea
There are 4.5 billion tonnes of uranium in sea water, a thousand times more than what is known to exist in uranium mines
The way ahead: BARC and the Commissariat a’ Energie Atomique (CEA), France, are collaborating to develop three innovative and efficient methods of uranium extraction.
Uranium in trace quantities is present in soil, rock and water. Bounteous nature leaves about 4.5 billion tonnes of uranium in sea water, a thousand times more than what is known to exist in uranium mines. Since its concentration is extremely low (only one particle of uranium for 34 million particles of other elements), harvesting uranium from sea is a formidable task.
Japanese technology
Japan developed a technology by using plastic sheets to which amidoxime, which is capable of selectively absorbing uranium from seawater, is grafted by high energy electron beam irradiation.
Scientists from the Desalination Division, Bhabha Atomic Research Centre recovered uranium at milligram levels from sea water using electron beam grafted amidoxime.
They developed a semi pilot scale facility to produce radiation grafted sheets of 1 metre X 1 metre size.
They collected about 800 microgrammes of uranium in five campaigns from CIRUS Jettyhead; about 1.8 milligrammes from the seawater intake and outfall canals at the Tarapur Atomic Power Station and around 200 microgrammes from Andaman and Nicobar Islands. Though these amounts are trivial, it gives confidence in the technology
Field trials carried out at the three locations gave concentration factors of 300, 600 and 700 for the submergence of the absorbent material for 12, 14 and 23 days respectively.
“What are the reasons for obtaining different concentration factors at different locations?” “The concentration factor depends on corrosion, bio-fouling and their combined effect on the adsorption kinetics. These may be different at different locations”, Dr P.K. Tewari, Head, Desalination Division, BARC responded to my query.
BARC scientists studied these factors and the mechanical properties of the materials used in the suspension assembly and the substrate. They established their compatibilities with seawater and process chemicals and the optimum submergence periods for various locations.
They also evaluated the potential of Polyhydroxamic Acid (PHOA) sorbent, for uptake of uranium from seawater. They obtained a concentration factor of over 190, when the resin, filled in a porous bag was dipped in seawater for a period ranging from 10-30 days.
BARC and the Commissariat a’ Energie Atomique (CEA), France, are collaborating to develop three innovative and efficient methods of uranium extraction from the concentrated brine rejected by integrated nuclear desalination systems, which both partners are currently developing.
The first method uses resin-grafted with calixarene (a synthetic material, indecently expensive!); magnetic separation is the second method and the third uses a canal system using absorbents.
These methods are highly selective but need further research and development.
Using three absorption cages, each of cross sectional area of 16 square metres and height of 16 cm and consisting of stacks of 52,000 uranium specific, non-woven sheets with a total mass of 350 kg, a Japanese group recovered more than one kg of uranium in terms of yellow cake during a submersion period of 240 days in the ocean.
Underwater farm
Dr Masao Tanada of the Japanese Atomic Energy Agency hopes to get funding to construct an under-water uranium farm covering nearly 400 square miles that would meet one-sixth of Japan’s annual uranium requirements.
Tanada asserts that Japan’s nuclear power industry can harvest the 8,000 tons it needs annually from the Kuroshio Current that flows along Japan’s eastern seaboard.
Japanese researchers found out that they can harvest uranium from sea by cultivating genetically engineered gulfweed which will grow in sea at an unbelievable rate of two metres an year. The weed selectively soaks up heavy metals including uranium.
A spin-off
What will you do with possibly the millions of tons of grass left over after recovering uranium? Convert it to bioethanol! Gulfweed is an ideal non-food source of bio-ethanol. Gulfweed traps carbondioxide from sea.
Conventional uranium mining requires environmental restoration including long term tailings management. Uranium recovery from the sea does not leave any tailings. With superb green credentials, it is an environmental friendly process.
India has miles to go to reach kilogramme capacities of uranium. BARC has plans to upgrade the capacity.
K.S. PARTHASARATHY
Raja Ramanna Fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
K.S.Parthasarathy
Date:12/11/2009 URL: http://www.thehindu.com/thehindu/seta/2009/11/12/stories/2009111250321300.htm
________________________________________
Back Sci Tech
Technologies to harvest uranium from sea
There are 4.5 billion tonnes of uranium in sea water, a thousand times more than what is known to exist in uranium mines
The way ahead: BARC and the Commissariat a’ Energie Atomique (CEA), France, are collaborating to develop three innovative and efficient methods of uranium extraction.
Uranium in trace quantities is present in soil, rock and water. Bounteous nature leaves about 4.5 billion tonnes of uranium in sea water, a thousand times more than what is known to exist in uranium mines. Since its concentration is extremely low (only one particle of uranium for 34 million particles of other elements), harvesting uranium from sea is a formidable task.
Japanese technology
Japan developed a technology by using plastic sheets to which amidoxime, which is capable of selectively absorbing uranium from seawater, is grafted by high energy electron beam irradiation.
Scientists from the Desalination Division, Bhabha Atomic Research Centre recovered uranium at milligram levels from sea water using electron beam grafted amidoxime.
They developed a semi pilot scale facility to produce radiation grafted sheets of 1 metre X 1 metre size.
They collected about 800 microgrammes of uranium in five campaigns from CIRUS Jettyhead; about 1.8 milligrammes from the seawater intake and outfall canals at the Tarapur Atomic Power Station and around 200 microgrammes from Andaman and Nicobar Islands. Though these amounts are trivial, it gives confidence in the technology
Field trials carried out at the three locations gave concentration factors of 300, 600 and 700 for the submergence of the absorbent material for 12, 14 and 23 days respectively.
“What are the reasons for obtaining different concentration factors at different locations?” “The concentration factor depends on corrosion, bio-fouling and their combined effect on the adsorption kinetics. These may be different at different locations”, Dr P.K. Tewari, Head, Desalination Division, BARC responded to my query.
BARC scientists studied these factors and the mechanical properties of the materials used in the suspension assembly and the substrate. They established their compatibilities with seawater and process chemicals and the optimum submergence periods for various locations.
They also evaluated the potential of Polyhydroxamic Acid (PHOA) sorbent, for uptake of uranium from seawater. They obtained a concentration factor of over 190, when the resin, filled in a porous bag was dipped in seawater for a period ranging from 10-30 days.
BARC and the Commissariat a’ Energie Atomique (CEA), France, are collaborating to develop three innovative and efficient methods of uranium extraction from the concentrated brine rejected by integrated nuclear desalination systems, which both partners are currently developing.
The first method uses resin-grafted with calixarene (a synthetic material, indecently expensive!); magnetic separation is the second method and the third uses a canal system using absorbents.
These methods are highly selective but need further research and development.
Using three absorption cages, each of cross sectional area of 16 square metres and height of 16 cm and consisting of stacks of 52,000 uranium specific, non-woven sheets with a total mass of 350 kg, a Japanese group recovered more than one kg of uranium in terms of yellow cake during a submersion period of 240 days in the ocean.
Underwater farm
Dr Masao Tanada of the Japanese Atomic Energy Agency hopes to get funding to construct an under-water uranium farm covering nearly 400 square miles that would meet one-sixth of Japan’s annual uranium requirements.
Tanada asserts that Japan’s nuclear power industry can harvest the 8,000 tons it needs annually from the Kuroshio Current that flows along Japan’s eastern seaboard.
Japanese researchers found out that they can harvest uranium from sea by cultivating genetically engineered gulfweed which will grow in sea at an unbelievable rate of two metres an year. The weed selectively soaks up heavy metals including uranium.
A spin-off
What will you do with possibly the millions of tons of grass left over after recovering uranium? Convert it to bioethanol! Gulfweed is an ideal non-food source of bio-ethanol. Gulfweed traps carbondioxide from sea.
Conventional uranium mining requires environmental restoration including long term tailings management. Uranium recovery from the sea does not leave any tailings. With superb green credentials, it is an environmental friendly process.
India has miles to go to reach kilogramme capacities of uranium. BARC has plans to upgrade the capacity.
K.S. PARTHASARATHY
Raja Ramanna Fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
Thursday, November 05, 2009
High fissile fuel in nuclear submarine lasts long
High fissile fuel in nuclear submarine lasts long
The prototype is serving as a training centre for the nuclear submarine crew
Reactor internals must be rugged and resilient
Reactor internals remain inaccessible for inspection
Every year, on October 30, scientists, engineers and other officials from the Department of Atomic Energy gather near the Central Complex Building, Trombay to celebrate the Founder’s Day. Being the Birth Centenary year of Dr. Homi Bhabha, this year’s celebration was unique. The stock taking of the research and development activities at the Bhabha Atomic Research Centre (BARC) covered compact reactor for Arihant (the nuclear submarine), improved gas centrifuges for uranium enrichment, fuel fabrication for fast reactors and work on innovative reactors among other areas in the cutting edge of technologies.
BARC designed, developed and built the steam generating unit of Arihant by facing many technical challenges
“The compact Pressurized Water Reactor was designed for this purpose with several features; such as very quick response for power ramping, extremely stable undership motions and resistance against exposure to very high acceleration resulting from eventual depth charges”, Dr Sukumar Banerjee, Director, BARC said in his Founder’s Day Address
“Since the nuclear reactor is fuelled with high fissile containing fuel, it can supply energy in the submerged condition for an extended period without refuelling”, he clarified. Details about the reactor are classified.
Generally, Pressurized Water Reactors (PWR) power nuclear submarines. A PWR has a core of highly enriched uranium. When uranium nuclei undergo fission, the fission fragments carry enormous energy. They dissipate the energy in the core which gets heated up. The high pressure primary system with water as coolant removes the heat from the core continuously.
Water at high temperature enters the steam generators. In the steam generators, the heat from the water in the primary system is transferred to the secondary system to create steam. In the secondary system, the steam flows from the steam generators to drive the turbine generators, which supply the ship with electricity, and to the main propulsion turbines, which drive the propeller. After passing through the turbines, the steam condenses into water which is fed back to the steam generators by the feed pumps.
Naval reactors pitch and roll. Demands of power change rapidly. The manufacturing and quality assurance of reactor components must be of exceptionally high standard.
The reactor internals remain inaccessible for inspection or replacement throughout the long life of their core. They must be rugged and resilient. Reactor components and systems must withstand, harsh and hostile environment, long term effects of radiation, corrosion, high temperature and pressure.
As the reactor operates radiation level increases. Appropriate shields are built around the reactors to ensure radiation safety. A reactor may use over 100 tons of lead as shielding.
“Many systems and equipment designed and built were first of its kind in the country. The entire steam generating plant has been designed to give highly reliable offshore operation in a completely isolated environment”, Dr Banerjee noted.
“Control and instrumentation design is fault tolerant and requires minimum operator interventions. An elaborate diagnostic system enables a very high availability factor. Many new materials and technologies have been developed and new infrastructure has been created for this project”, he revealed.
Prototype system
The development of the steam generating plant of Arihant was preceded by setting up of the land based prototype system at Kalpakkam. The reactor which has been working for the past three years has served as a technology demonstrator.
“The entire plant with primary, secondary, electrical and propulsion system along with its integrated control was packed in the aft end of a land based submarine hull designed and built specifically for the purpose.
This protoype is serving as a training centre for the crew for the nuclear submarine”, Dr Banerjee said. The crew gets training with the help of an indigenously designed and built full scope simulator.
K.S. PARTHASARATHY
Raja Ramanna fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk)
© Copyright 2000 - 2009 The Hindu
Thursday, October 29, 2009
Can low doses of radiation cause heart disease?
It is necessary to assess the epidemiological evidence of radiation effects other than cancer at low doses
Basic guideline: The basic tenet of radiation protection that radiation doses to workers should remain As Low As Reasonably Achievable remains.
Researchers at the Imperial College, London predict a link between low dose radiation exposure and heart disease (PLoS Computational Biology, October 2009). Their mathematical model suggests that the risk would increase as the dose increases.
Cardiovascular effect of high levels of radiation has been known in patients who underwent radiotherapy. Specialists found higher risk for cardiovascular disease among women treated for left-sided breast cancer when compared with women treated for right-sided breast cancer, during the period more than 10 years after diagnosis.
Emerging evidence
There is emerging evidence of excess risk of heart disease at much lower doses occurring after a long time after exposure among the A-bomb survivors included in the Life Span Study project and in some groups of radiation workers. The likely mechanism to explain the effect was not clear.
The US National Academy of Science’s Committee for Biological Effects of Ionizing Radiation (BEIR committee) in its latest report has acknowledged the existence of such effects; it asserted that the available data are inadequate to quantify the risk, if it exists.
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in its latest report published in 2008, clarified that it is necessary to assess the epidemiological evidence of radiation effects other than cancer at low doses because the phenomena is potentially important for radiation risk assessment at these dose levels, and there is considerable lack of consistency among the available epidemiological data.
“The Committee considered it important to focus on cardiovascular disease as the major endpoint of interest, because cardiovascular disease is among the most common diseases in many populations worldwide and thus may be important for radiation risk assessment,” the report cautioned.
The Imperial College team suggested that radiation kills monocytes (a type of white blood cell) in the arterial wall, which would otherwise bind to monocyte chemo-attractant protein 1 (MCP-1). The resultant higher levels of MCP-1 cause inflammation which leads to cardiovascular disease.
According to the researchers, the predicted consequence of several small radiation exposures is to cause mean concentration of MCP1 to increase linearly with cumulative dose.
“The radiation-induced risks predicted by the model is consistent with those observed in a number of occupationally observed groups,” they claimed.
The implications
According to them, if their model is valid, it will have substantive implications in radiological protection, which currently does not take cardiovascular diseases into consideration.
In an interview to BBC, Professor Steve Jones, of Westlakes Research Institute who formerly worked for British Nuclear Fuels (BNF) and who has published his own research on the links between radiation and circulatory disease in nuclear workers conceded that the results of the mathematical model were interesting. He cautioned that its finding cannot be taken as definitive as it is based very largely on mathematical modelling.
“However it does propose a plausible biological mechanism and, most importantly, a mechanism that is testable by experiment.” he clarified to the BBC.
BBC quoted Professor Richard Wakeford, of the University of Manchester who also formerly worked for BNF, thus: “More research like this is needed if the results of epidemiological studies are to be properly understood, but there is still some way to go before it may be reliably concluded that low-level radiation can increase the risk of circulatory disease.”
According to BBC, Professor Dudley Goodhead, former director of the MRC Radiation and Genome Stability Unit, noted that this paper puts forward a highly complicated mathematical model, which makes many assumptions, to explore one possible causal mechanism.
“Such conclusions should not be drawn without laboratory validation of the key assumptions,” he asserted.
For many years, the model proposed by the Imperial college team may remain just that; a model with no practical implications.
The basic tenet of radiation protection that radiation doses to workers should remain As Low As Reasonably Achievable (ALARA principle) remains.
Scientists from the Regional Cancer Centre, Thiruvananthapuram and Bhabha Atomic Research Centre did not find any excess cancer in the high background radiation areas (HBRA) in Kerala. It will be worthwhile to look for excess cardiac diseases in HBRA.
K.S. PARTHASARATHY
RAJA RAMANNA FELLOW, DEPARTMENT OF ATOMIC ENERGY
ksparth@yahoo.co.uk
© Copyright 2000 - 2009 The Hindu
Saturday, October 24, 2009
How safe is Madras Atomic Power Station?
South Asians Against Nukes (SAAN) , a Non Governmental Organization has claimed that the radiation levels are high in regions around the Madras Atomic Power Station. They measured the levels by using their own gamma monitor. The results indicate either that they were measuring the widely varying background radiation levels because of the presence of thorium in the soil or they wee using a defective instrument. Since they obtained abnormally high values, there instrument must have been defective!
The author had similar experience when another NGO claimed that the background radiation levels in Lucknow was very high. It turned out that the instrument they used was light sensitive!
K.S.Parthasarathy
How safe is Madras Atomic Power Station?
Within threshold: The releases from the Madras Atomic Power Station have not exceeded the limits prescribed by the regulatory agency.
Background radiation level at any place depends mainly on terrestrial radiation from natural radionuclides such as uranium, thorium and their decay products and potassium-40 present in soil and on cosmic rays (radiation from outer space).
The top one metre soil in a land of area 0.1 acre anywhere in the country may contain 1.28 kg of potassium-40, 3.6 kg of thorium and one kg of uranium.
The soil factor
In different soils these values may be higher or lower. The dose due to natural radiation varies from place to place.
The releases from the Madras Atomic Power Station (MAPS) have not exceeded the limits prescribed by the regulatory agency. The data collected from 1982 to date by the Environmental Survey Laboratory (ESL) at MAPS do not indicate high increases in radiation levels. Nuclear Power Corporation Limited should invite students and public to the ESL to reassure them. BARC scientists have measured outdoor natural gamma radiation levels at 214 locations in different parts of India continuously over a year by using special dosimeters and got an average annual value of 775 microgray.
They got the highest value of 26730 microgray at Chavara, Kerala. (Gray is a unit of radiation dose.
Energy absorbed
When the dose is one gray, the energy from ionizing radiation absorbed is one joule per kg; since gray is a big unit, submutiples such as milli-one thousandth or micro -one millionth-of a gray are usually used).
Using the geological data on the types of rocks and the abundance of uranium, thorium and potassium in these rocks, BARC scientists prepared a radiation map of the country in 1986.
The natural background radiation doses at Mumbai, Kolkata, Chennai and Bangalore are 484, 810, 790 and 825 microgray per year respectively.
The annual cosmic ray dose itself varies from 280 microgray in Chennai to 440 microgray in Bangalore which is 921 metres above the sea level.
Variation of a few hundred microgray is not unusual.
What is the extra contribution, if any, to radiation dose made by a nuclear power station at its fence post?
Data from 1982 to 2007 indicate that for the MAPS, the lowest extra dose was 7.2 microsievert per year and the highest 86.3 microsievert per year. (Sievert — Sv — is another unit. For all practical purposes, background radiation expressed in sievert or gray may be considered numerically equal). These are much less than the AERB limit of 1,000 microsievert.
The status is similar in other power stations.
Activity can escape only if several barriers (ceramic fuel, its cladding, coolant, coolant tube etc) are broken. These are of proven quality. Fail safe devices including redundant and diverse safety systems ensure that such uncontrolled releases do not happen.
In April 1994, an “environmentalist” measured high radiation levels at the MLAs’ hostel and other locations in Lucknow. “Radiation levels at some points are higher than those at Chernobyl,” he claimed. Many newspapers published the story.
Recorded normal
A team of scientists sent by the Atomic Energy Regulatory Board (AERB) found that his Geiger-Mueller counter —based instrument was defective. It was light sensitive. When the detector was made light-proof, the radiation levels recorded normal!
In 2005, Padmanabhan and Nakul of the South Asians Against Nukes (SAAN) claimed that while monitoring radiation levels around the Madras Atomic Power Station in places such as Coimbatore, Chenglepet, Mahabalipuram and Kalpakkam they came across several spots with gamma radiation levels as high as a few millisievert to above ten millisieverts per year. The highest level measured was 54.5 millisieverts.
The speculation
They speculated that the wide variations between the readings taken from the same spot indicated that the source of radiation is not on the ground but are “picoparticles” from uranium fission floating and flying in air! There are simpler explanations.
If they were using a defect-free instrument, they were recording radiation from thorium rich soil in the region. This is nothing unusual.
Since over 70 per cent of their readings were above 2mSv, I believe that they were experiencing the problem faced by the “environmentalist” in Lucknow!
K.S.PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
The author had similar experience when another NGO claimed that the background radiation levels in Lucknow was very high. It turned out that the instrument they used was light sensitive!
K.S.Parthasarathy
How safe is Madras Atomic Power Station?
Within threshold: The releases from the Madras Atomic Power Station have not exceeded the limits prescribed by the regulatory agency.
Background radiation level at any place depends mainly on terrestrial radiation from natural radionuclides such as uranium, thorium and their decay products and potassium-40 present in soil and on cosmic rays (radiation from outer space).
The top one metre soil in a land of area 0.1 acre anywhere in the country may contain 1.28 kg of potassium-40, 3.6 kg of thorium and one kg of uranium.
The soil factor
In different soils these values may be higher or lower. The dose due to natural radiation varies from place to place.
The releases from the Madras Atomic Power Station (MAPS) have not exceeded the limits prescribed by the regulatory agency. The data collected from 1982 to date by the Environmental Survey Laboratory (ESL) at MAPS do not indicate high increases in radiation levels. Nuclear Power Corporation Limited should invite students and public to the ESL to reassure them. BARC scientists have measured outdoor natural gamma radiation levels at 214 locations in different parts of India continuously over a year by using special dosimeters and got an average annual value of 775 microgray.
They got the highest value of 26730 microgray at Chavara, Kerala. (Gray is a unit of radiation dose.
Energy absorbed
When the dose is one gray, the energy from ionizing radiation absorbed is one joule per kg; since gray is a big unit, submutiples such as milli-one thousandth or micro -one millionth-of a gray are usually used).
Using the geological data on the types of rocks and the abundance of uranium, thorium and potassium in these rocks, BARC scientists prepared a radiation map of the country in 1986.
The natural background radiation doses at Mumbai, Kolkata, Chennai and Bangalore are 484, 810, 790 and 825 microgray per year respectively.
The annual cosmic ray dose itself varies from 280 microgray in Chennai to 440 microgray in Bangalore which is 921 metres above the sea level.
Variation of a few hundred microgray is not unusual.
What is the extra contribution, if any, to radiation dose made by a nuclear power station at its fence post?
Data from 1982 to 2007 indicate that for the MAPS, the lowest extra dose was 7.2 microsievert per year and the highest 86.3 microsievert per year. (Sievert — Sv — is another unit. For all practical purposes, background radiation expressed in sievert or gray may be considered numerically equal). These are much less than the AERB limit of 1,000 microsievert.
The status is similar in other power stations.
Activity can escape only if several barriers (ceramic fuel, its cladding, coolant, coolant tube etc) are broken. These are of proven quality. Fail safe devices including redundant and diverse safety systems ensure that such uncontrolled releases do not happen.
In April 1994, an “environmentalist” measured high radiation levels at the MLAs’ hostel and other locations in Lucknow. “Radiation levels at some points are higher than those at Chernobyl,” he claimed. Many newspapers published the story.
Recorded normal
A team of scientists sent by the Atomic Energy Regulatory Board (AERB) found that his Geiger-Mueller counter —based instrument was defective. It was light sensitive. When the detector was made light-proof, the radiation levels recorded normal!
In 2005, Padmanabhan and Nakul of the South Asians Against Nukes (SAAN) claimed that while monitoring radiation levels around the Madras Atomic Power Station in places such as Coimbatore, Chenglepet, Mahabalipuram and Kalpakkam they came across several spots with gamma radiation levels as high as a few millisievert to above ten millisieverts per year. The highest level measured was 54.5 millisieverts.
The speculation
They speculated that the wide variations between the readings taken from the same spot indicated that the source of radiation is not on the ground but are “picoparticles” from uranium fission floating and flying in air! There are simpler explanations.
If they were using a defect-free instrument, they were recording radiation from thorium rich soil in the region. This is nothing unusual.
Since over 70 per cent of their readings were above 2mSv, I believe that they were experiencing the problem faced by the “environmentalist” in Lucknow!
K.S.PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
Thursday, October 15, 2009
Nuclear power: myths, realities
Nuclear power suffered because of accidents. But no one abandoned it because of accidents.Nuclear power seems to be an “unloved” industry, not because it is faulty. Mired in controversy, myths about nuclear power survive; the realities are unknown to many.Author highlights some of thew myths and the realities about this "unloved" industry
K.S.Parthasarathy
Date:15/10/2009 URL: http://www.thehindu.com/thehindu/seta/2009/10/15/stories/2009101550201400.htm Back Sci Tech
Nuclear power: myths, realities
Nuclear power suffered because of accidents. But no one abandoned it because of accidents
The impact of water used as coolant may extend up to about 500 metres from the discharge point
The doses to members of the public are too small and well within the AERB limit
The speakers at a well attended side event at the recently held International Conference on Peaceful Uses of Atomic Energy at Delhi (September 29-October 1) recommended a proactive, public awareness programme on issues related to energy, particularly nuclear energy.
International Atomic Energy Agency (IAEA), Department of Atomic Energy and Indian Nuclear Society jointly organized the meeting.
Nuclear power seems to be an “unloved” industry, not because it is faulty. Mired in controversy, myths about nuclear power survive; the realities are unknown to many.
Nuclear power suffered because of accidents. But no one abandoned it because of accidents at Three Mile Island (1979) and Chernobyl (1986).
U.S. electric companies connected 50 out of the currently operating 104 nuclear power reactors since 1979; nineteen of these after 1986. Canadian companies connected all the 14 operating nuclear power reactors to the grid after 1979. Of the fifty nine French reactors, 53 came on line after 1979.
Some European nations decided to phase out nuclear power. Since they are substitutes for fossil power stations (which are implicated in global warning), these nations are decisively moving away from their “phase out” decision.
Recently, “National Alliance of Anti-nuclear Movements (NAAM)” claimed that the nuclear plant at Kudankulam would lead to pollution in the near shore areas, affecting fish stocks. They alleged that this would impact on the health of fish-eating people in Kerala, Tamil Nadu and Sri Lanka (The Hindu, October 3). These allegations have no scientific basis. Pollution of sea shore is another myth!
Fish catch potential during 1994-98, in the Kalpakkam zone indicated variations. Central Marine and Fisheries Research Institute, Cochin, concluded that these variations are mere statistical variations with seasons.
The impact of water used to cool nuclear power reactors is limited to a mixing zone which may extend up to about 500 metres from the discharge point.
India has been operating nuclear power stations since 1969.
The Atomic Energy Regulatory Board (AERB) permits stations to release radioactivity up to certain prescribed limits. The scientists at the Environmental Survey Laboratory (ESL) outside each station use state-of-the-art methods to measure radioactivity in samples of air, water, soil, sediments and foodstuffs and look for trends, if any.
The doses to members of the public are too small and well within the AERB limit. They are within the variation of natural background radiation present everywhere even in the absence of the power station.
The radiation dose due to Kudankulam reactors will also be similar. An activist alleged that these reactors would trigger cancer and genetic disorders in the area (The Hindu, Oct, 3). This is a preposterous allegation.
The claim that iodine-131 released from Kalpakkam nuclear power station into sea and air is causing thyroid cancer in the area in another myth.
The release of iodine to sea is virtually zero. During 1983-2008, the annual releases into air were zero to 1.29 per cent of the AERB limit. The doses due to this were too trivial to cause cancer.
The Iodine-131 activity, if any, released from the station will get deposited on grass. It will appear promptly in goats’ thyroid. ESL scientists routinely measure iodine-131 from goats’ thyroid, an easily available sample.
They detected iodine-131 activities only twice, in 1976 during the aftermath of Chinese nuclear tests in the atmosphere and in 1986 shortly after the accident at the Chernobyl nuclear power station.
“The ESL Kalpakkam had found after the nuclear accident at Chernobyl in April 1986 that the incidence of thyroid related diseases in goats had registered an increase as a result of feeding on grass laced with Iodine-131”.
An activist wrote in a Chennai daily on October 18, 2008 (NUCLEAR FREE INDIA, December 2008).Obviously, he mistook why ESL scientists collect goats’ thyroid samples!
According to an activist, the scientific community was yet to come up with a safe nuclear waste management system (The Hindu Oct, 3). Another myth!
Nuclear wastes are managed safely. There is scientific consensus on safe management of high level nuclear waste; but that problem is mired in politics.
If you want nuclear power to thrive, dispel the myths, reveal the realities!
( ksparth@yahoo.co.uk )
K.S. PARTHASARATHY
FORMER SECRETARY, AERB
K.S.Parthasarathy
Date:15/10/2009 URL: http://www.thehindu.com/thehindu/seta/2009/10/15/stories/2009101550201400.htm Back Sci Tech
Nuclear power: myths, realities
Nuclear power suffered because of accidents. But no one abandoned it because of accidents
The impact of water used as coolant may extend up to about 500 metres from the discharge point
The doses to members of the public are too small and well within the AERB limit
The speakers at a well attended side event at the recently held International Conference on Peaceful Uses of Atomic Energy at Delhi (September 29-October 1) recommended a proactive, public awareness programme on issues related to energy, particularly nuclear energy.
International Atomic Energy Agency (IAEA), Department of Atomic Energy and Indian Nuclear Society jointly organized the meeting.
Nuclear power seems to be an “unloved” industry, not because it is faulty. Mired in controversy, myths about nuclear power survive; the realities are unknown to many.
Nuclear power suffered because of accidents. But no one abandoned it because of accidents at Three Mile Island (1979) and Chernobyl (1986).
U.S. electric companies connected 50 out of the currently operating 104 nuclear power reactors since 1979; nineteen of these after 1986. Canadian companies connected all the 14 operating nuclear power reactors to the grid after 1979. Of the fifty nine French reactors, 53 came on line after 1979.
Some European nations decided to phase out nuclear power. Since they are substitutes for fossil power stations (which are implicated in global warning), these nations are decisively moving away from their “phase out” decision.
Recently, “National Alliance of Anti-nuclear Movements (NAAM)” claimed that the nuclear plant at Kudankulam would lead to pollution in the near shore areas, affecting fish stocks. They alleged that this would impact on the health of fish-eating people in Kerala, Tamil Nadu and Sri Lanka (The Hindu, October 3). These allegations have no scientific basis. Pollution of sea shore is another myth!
Fish catch potential during 1994-98, in the Kalpakkam zone indicated variations. Central Marine and Fisheries Research Institute, Cochin, concluded that these variations are mere statistical variations with seasons.
The impact of water used to cool nuclear power reactors is limited to a mixing zone which may extend up to about 500 metres from the discharge point.
India has been operating nuclear power stations since 1969.
The Atomic Energy Regulatory Board (AERB) permits stations to release radioactivity up to certain prescribed limits. The scientists at the Environmental Survey Laboratory (ESL) outside each station use state-of-the-art methods to measure radioactivity in samples of air, water, soil, sediments and foodstuffs and look for trends, if any.
The doses to members of the public are too small and well within the AERB limit. They are within the variation of natural background radiation present everywhere even in the absence of the power station.
The radiation dose due to Kudankulam reactors will also be similar. An activist alleged that these reactors would trigger cancer and genetic disorders in the area (The Hindu, Oct, 3). This is a preposterous allegation.
The claim that iodine-131 released from Kalpakkam nuclear power station into sea and air is causing thyroid cancer in the area in another myth.
The release of iodine to sea is virtually zero. During 1983-2008, the annual releases into air were zero to 1.29 per cent of the AERB limit. The doses due to this were too trivial to cause cancer.
The Iodine-131 activity, if any, released from the station will get deposited on grass. It will appear promptly in goats’ thyroid. ESL scientists routinely measure iodine-131 from goats’ thyroid, an easily available sample.
They detected iodine-131 activities only twice, in 1976 during the aftermath of Chinese nuclear tests in the atmosphere and in 1986 shortly after the accident at the Chernobyl nuclear power station.
“The ESL Kalpakkam had found after the nuclear accident at Chernobyl in April 1986 that the incidence of thyroid related diseases in goats had registered an increase as a result of feeding on grass laced with Iodine-131”.
An activist wrote in a Chennai daily on October 18, 2008 (NUCLEAR FREE INDIA, December 2008).Obviously, he mistook why ESL scientists collect goats’ thyroid samples!
According to an activist, the scientific community was yet to come up with a safe nuclear waste management system (The Hindu Oct, 3). Another myth!
Nuclear wastes are managed safely. There is scientific consensus on safe management of high level nuclear waste; but that problem is mired in politics.
If you want nuclear power to thrive, dispel the myths, reveal the realities!
( ksparth@yahoo.co.uk )
K.S. PARTHASARATHY
FORMER SECRETARY, AERB
Friday, October 02, 2009
How safe are interventional cardiac procedures?
Radiation safety in interventional radiology practices are getting some attention now
The Hindu published an artcile on October 1, 2009
Dr K.S.Parthasarathy
Date:01/10/2009 URL: http://www.thehindu.com/thehindu/seta/2009/10/01/stories/2009100150441500.htm
________________________________________
How safe are interventional cardiac procedures?
— Photo: S. Thanthoni
Within threshold: Radiation risk is acceptably low when compared to risk of not carrying out the procedures when indicated.
Recently, radiation protection measures in interventional radiology especially in cardiology have been receiving special attention.
These are image-guided therapeutic techniques such as coronary angioplasty (to remove blockades in artery) and diagnostic techniques such as angiography (imaging the blood vessels using an x-ray contrasting agent).
These life-saving procedures require specially designed equipment and involve high radiation exposures to physicians, technologists and patients. Cardiologists must know the equipment specification and characteristics to use radiation effectively and optimally.
Risks compared
Radiation risk is acceptably low when compared to risk of not carrying out the procedures when they are medically indicated.
Recently, a survey supported by the International Atomic Energy Agency (IAEA) in 55 hospitals in 20 countries of Africa, Asia, and Europe indicated that many patients exceeded the dose threshold for erythema (skin reddening); a substantial number (62 per cent) of coronary angioplasty procedures exposed patients to doses above the recommended dose reference level. (American Journal of Roentgenology, August 2009). Though specially needed dose measuring instruments were in place in almost half the facilities, none had experience in its use.
Hundred out of 505 patients monitored, had peak skin doses above the 2-Gy threshold for deterministic effects (Gy is a unit of radiation dose; one Gy is equal to one joule per kg).
Inadequately trained
IAEA has noted that many physicians using interventional radiology techniques are not adequately trained in radiation safety or radiobiology. In a few cases, patients may suffer radiation-induced skin injuries which may go unnoticed. Younger patients may face an increased risk of future cancer.
Patients may ask their physicians about the radiation dose they are likely to get in the procedure. If they feel any changes in the exposed area of the skin later, they must report it to their physician. Though radiation dose is important, it is only one of the factors to be considered.
The dose to patients must be As Low As Reasonable Achievable (ALARA). Cardiac procedures are very complex, doses will be ALARA only if the cardiologists appreciate the importance of dose reduction; they must be constantly vigilant. If patient’s dose is reduced, occupational dose also will be reduced.
A few years ago, a medical physicist working in a corporate hospital introduced me to an eminent cardiologist who has been saving hundreds of lives. “When I have too many patients, I just remove the personnel monitoring badge”, he confessed. Unknown to him, he may become a victim of his carelessness.
Regular monitoring
Cardiologists must monitor their radiation doses regularly; they are among the category of radiation workers who have highest probability to get significant doses.
IAEA surveys conducted during training courses in which cardiologists from 56 countries participated showed that only 33 to 77 per cent of them use personnel dose measuring devices routinely.
During a workshop in Mumbai two cardiologists listed several telling deficiencies ( http://www.aerb.gov.in/t/newsflash/cathlab.pdf).
Cardiologists are not aware of the radiological safety precautions to be taken during angiography or angioplasty. They lack awareness of personal protective equipment, personnel dose monitoring devices and their proper use.
Lens of the eye is radiosensitive. Cardiologists remain near x-ray sources within high scatter radiation areas for several hours every day.
Preliminary results from the IAEA study called Retrospective Evaluation of Lens Injuries and Dose (RELID) indicate identifiable damage to the lens of those cardiologists not using eye protection.
A summary of the results of studies carried out in Colombia, Malaysia, Uruguay and Bulgaria during 2008-09 is freely available (http://rpop.iaea.org/RPOP/RPoP/Content/News/relid-activities.htm). Protracted eye lens dose of 4Gy over 3 months or 5.5 Gy delivered over five months may cause detectable opacities to the eye lens.
IAEA has been very active in the field of radiation protection. They offer educational material of inestimable value free at their web site (http://rpop.iaea.org/).
The International Commission on Radiological Protection has issued its publication No 85 titled “Avoidance of radiation injuries from medical interventional procedures” ( http://www.icrp.org/
educational_area.asp).
K.S. PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
The Hindu published an artcile on October 1, 2009
Dr K.S.Parthasarathy
Date:01/10/2009 URL: http://www.thehindu.com/thehindu/seta/2009/10/01/stories/2009100150441500.htm
________________________________________
How safe are interventional cardiac procedures?
— Photo: S. Thanthoni
Within threshold: Radiation risk is acceptably low when compared to risk of not carrying out the procedures when indicated.
Recently, radiation protection measures in interventional radiology especially in cardiology have been receiving special attention.
These are image-guided therapeutic techniques such as coronary angioplasty (to remove blockades in artery) and diagnostic techniques such as angiography (imaging the blood vessels using an x-ray contrasting agent).
These life-saving procedures require specially designed equipment and involve high radiation exposures to physicians, technologists and patients. Cardiologists must know the equipment specification and characteristics to use radiation effectively and optimally.
Risks compared
Radiation risk is acceptably low when compared to risk of not carrying out the procedures when they are medically indicated.
Recently, a survey supported by the International Atomic Energy Agency (IAEA) in 55 hospitals in 20 countries of Africa, Asia, and Europe indicated that many patients exceeded the dose threshold for erythema (skin reddening); a substantial number (62 per cent) of coronary angioplasty procedures exposed patients to doses above the recommended dose reference level. (American Journal of Roentgenology, August 2009). Though specially needed dose measuring instruments were in place in almost half the facilities, none had experience in its use.
Hundred out of 505 patients monitored, had peak skin doses above the 2-Gy threshold for deterministic effects (Gy is a unit of radiation dose; one Gy is equal to one joule per kg).
Inadequately trained
IAEA has noted that many physicians using interventional radiology techniques are not adequately trained in radiation safety or radiobiology. In a few cases, patients may suffer radiation-induced skin injuries which may go unnoticed. Younger patients may face an increased risk of future cancer.
Patients may ask their physicians about the radiation dose they are likely to get in the procedure. If they feel any changes in the exposed area of the skin later, they must report it to their physician. Though radiation dose is important, it is only one of the factors to be considered.
The dose to patients must be As Low As Reasonable Achievable (ALARA). Cardiac procedures are very complex, doses will be ALARA only if the cardiologists appreciate the importance of dose reduction; they must be constantly vigilant. If patient’s dose is reduced, occupational dose also will be reduced.
A few years ago, a medical physicist working in a corporate hospital introduced me to an eminent cardiologist who has been saving hundreds of lives. “When I have too many patients, I just remove the personnel monitoring badge”, he confessed. Unknown to him, he may become a victim of his carelessness.
Regular monitoring
Cardiologists must monitor their radiation doses regularly; they are among the category of radiation workers who have highest probability to get significant doses.
IAEA surveys conducted during training courses in which cardiologists from 56 countries participated showed that only 33 to 77 per cent of them use personnel dose measuring devices routinely.
During a workshop in Mumbai two cardiologists listed several telling deficiencies ( http://www.aerb.gov.in/t/newsflash/cathlab.pdf).
Cardiologists are not aware of the radiological safety precautions to be taken during angiography or angioplasty. They lack awareness of personal protective equipment, personnel dose monitoring devices and their proper use.
Lens of the eye is radiosensitive. Cardiologists remain near x-ray sources within high scatter radiation areas for several hours every day.
Preliminary results from the IAEA study called Retrospective Evaluation of Lens Injuries and Dose (RELID) indicate identifiable damage to the lens of those cardiologists not using eye protection.
A summary of the results of studies carried out in Colombia, Malaysia, Uruguay and Bulgaria during 2008-09 is freely available (http://rpop.iaea.org/RPOP/RPoP/Content/News/relid-activities.htm). Protracted eye lens dose of 4Gy over 3 months or 5.5 Gy delivered over five months may cause detectable opacities to the eye lens.
IAEA has been very active in the field of radiation protection. They offer educational material of inestimable value free at their web site (http://rpop.iaea.org/).
The International Commission on Radiological Protection has issued its publication No 85 titled “Avoidance of radiation injuries from medical interventional procedures” ( http://www.icrp.org/
educational_area.asp).
K.S. PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk )
© Copyright 2000 - 2009 The Hindu
Sunday, September 13, 2009
Scientists find direct link between CT scan and cellular damage
S & T » Science
August 18, 2009
Scientists find direct link between CT scan and cellular damage
K. S. Parthasarathy
A new research paper shows that radiation doses over time were less damaging than a single dose delivered all at once. In this 2005-file photo, a patient undergoing a test on computed tomography multi-detector 16 slice scanner at a hospital in India. Photo: K. R. Deepak.
Related
TOPICS
science and technology science (general)
health
X-rays induce many types of lesions (tiny biological damage) in the tissues through which they pass. They include breaks of one strand or both strands of the cellular DNA. Cells repair most of the former lesions promptly. Double Strand Break (DSB) is probably the most important effect. Scientists have developed extremely sensitive methods to assay DSBs caused by a single computed tomography (CT) test.
Cell repair
Cells can either repair DSBs properly restoring overall integrity of the genome, or mis-repair, resulting in drastic consequences such as cancer.
Kufner, Schwab and colleagues, researchers from Germany, described a method to measure biological dose in computed tomography (CT) scanning procedures (European Congress of Radiology, 2009). They demonstrated Double Strand Breaks (DSBs) of DNA in the white blood cells of patients undergoing cardiac CT and angiography examinations by sampling blood from the patients before and after the tests.
Physical energy absorbed by tissue is an imperfect indicator of what goes on in the tissue. A true estimate of radiation risk requires an accurate, reproducible biological measurement of radiation-induced damage, (auntminnie.com, 2009). By counting the DSBs, the researchers measured such a biological quantity.
Assay method
Radiation exposure causes DSBs in mammalian cells. When cells are exposed to radiation, certain types of molecules called histone H2AX, adjacent to the nascent breaks, undergo “phosphorylation” (a process involving specific biochemical changes).
The response is highly amplified and rapid; hundreds to thousands of H2AX molecules join within minutes. This newly phosphorylated protein called gamma-H2AX mobilises DNA repair proteins and form discrete foci, one per DSB. Specialists count these biomarkers by using immuno-fluorescence microscopy.
Counting of DSBs is thousand times more sensitive than other biological methods such as counting of chromosome aberrations.
A dose of one mGy (typical skin dose in medical x-ray examinations) generates on average one track per nucleus and thus is considered the lowest dose that can affect a whole cell. With one mGy, nearly 3 per cent of irradiated cells can sustain a DNA DSB. (Bonner, Proceedings of the National Academy of Sciences, April 23, 2003)
Medical X–ray procedures
Researchers examined 32 patients, 16 on each of two CT scanners using various protocols. They collected blood samples before and 30 minutes after the CT scan and counted the DSBs formed. They found that the number of DSBs increased linearly with dose length product, a normally used physical parameter
They observed that sequential CT scans are less biologically damaging than spiral CT. Radiation dose delivered over time was less damaging than the same dose delivered all at once. They did not observe any abnormal DNA damage in the blood cells of interventional radiologists when measured repeatedly throughout the normal working day.
The researchers demonstrated the presence of DSBs in the blood cells of all 37 patients undergoing conventional angiography. The number of DSBs at the end of the procedure varied widely, declining rapidly after the examinations due to DSB repair processes.
The sensitive methods evolved by the researchers may be very useful in understanding the mechanisms of cellular damage. It may help to evolve better cancer treatment strategies. Cancer cells are rogue cells with no rules. If they have any rules they are their own rules!
CT, a unique tool
The findings referred to in this article indicate the unparalleled technological advances in the study of cells and do not in any way diminish the potential use of computed tomography or conventional angiography in clinically indicated instances. CT scan unit is a unique tool to diagnose disease, trauma or abnormality and to plan, guide and monitor treatment.
It will cause harm to the patient if he refuses CT examinations prescribed by a qualified physician. For such tests, the benefit far outweighs the possible harm. Technological revolutions should not skew perception of risks.
(The author is a Former Secretary, Atomic Energy Regulatory Board, India. He can be contacted at: ksparth@yahoo.co.uk )
Keywords: CT Scan, DNA, K.S. Parthasarathy, Radiation,
________________________________________
Printable version | Aug 22, 2009 8:24:48 AM | http://beta.thehindu.com/sci-tech/science/article4850.ece
August 18, 2009
Scientists find direct link between CT scan and cellular damage
K. S. Parthasarathy
A new research paper shows that radiation doses over time were less damaging than a single dose delivered all at once. In this 2005-file photo, a patient undergoing a test on computed tomography multi-detector 16 slice scanner at a hospital in India. Photo: K. R. Deepak.
Related
TOPICS
science and technology science (general)
health
X-rays induce many types of lesions (tiny biological damage) in the tissues through which they pass. They include breaks of one strand or both strands of the cellular DNA. Cells repair most of the former lesions promptly. Double Strand Break (DSB) is probably the most important effect. Scientists have developed extremely sensitive methods to assay DSBs caused by a single computed tomography (CT) test.
Cell repair
Cells can either repair DSBs properly restoring overall integrity of the genome, or mis-repair, resulting in drastic consequences such as cancer.
Kufner, Schwab and colleagues, researchers from Germany, described a method to measure biological dose in computed tomography (CT) scanning procedures (European Congress of Radiology, 2009). They demonstrated Double Strand Breaks (DSBs) of DNA in the white blood cells of patients undergoing cardiac CT and angiography examinations by sampling blood from the patients before and after the tests.
Physical energy absorbed by tissue is an imperfect indicator of what goes on in the tissue. A true estimate of radiation risk requires an accurate, reproducible biological measurement of radiation-induced damage, (auntminnie.com, 2009). By counting the DSBs, the researchers measured such a biological quantity.
Assay method
Radiation exposure causes DSBs in mammalian cells. When cells are exposed to radiation, certain types of molecules called histone H2AX, adjacent to the nascent breaks, undergo “phosphorylation” (a process involving specific biochemical changes).
The response is highly amplified and rapid; hundreds to thousands of H2AX molecules join within minutes. This newly phosphorylated protein called gamma-H2AX mobilises DNA repair proteins and form discrete foci, one per DSB. Specialists count these biomarkers by using immuno-fluorescence microscopy.
Counting of DSBs is thousand times more sensitive than other biological methods such as counting of chromosome aberrations.
A dose of one mGy (typical skin dose in medical x-ray examinations) generates on average one track per nucleus and thus is considered the lowest dose that can affect a whole cell. With one mGy, nearly 3 per cent of irradiated cells can sustain a DNA DSB. (Bonner, Proceedings of the National Academy of Sciences, April 23, 2003)
Medical X–ray procedures
Researchers examined 32 patients, 16 on each of two CT scanners using various protocols. They collected blood samples before and 30 minutes after the CT scan and counted the DSBs formed. They found that the number of DSBs increased linearly with dose length product, a normally used physical parameter
They observed that sequential CT scans are less biologically damaging than spiral CT. Radiation dose delivered over time was less damaging than the same dose delivered all at once. They did not observe any abnormal DNA damage in the blood cells of interventional radiologists when measured repeatedly throughout the normal working day.
The researchers demonstrated the presence of DSBs in the blood cells of all 37 patients undergoing conventional angiography. The number of DSBs at the end of the procedure varied widely, declining rapidly after the examinations due to DSB repair processes.
The sensitive methods evolved by the researchers may be very useful in understanding the mechanisms of cellular damage. It may help to evolve better cancer treatment strategies. Cancer cells are rogue cells with no rules. If they have any rules they are their own rules!
CT, a unique tool
The findings referred to in this article indicate the unparalleled technological advances in the study of cells and do not in any way diminish the potential use of computed tomography or conventional angiography in clinically indicated instances. CT scan unit is a unique tool to diagnose disease, trauma or abnormality and to plan, guide and monitor treatment.
It will cause harm to the patient if he refuses CT examinations prescribed by a qualified physician. For such tests, the benefit far outweighs the possible harm. Technological revolutions should not skew perception of risks.
(The author is a Former Secretary, Atomic Energy Regulatory Board, India. He can be contacted at: ksparth@yahoo.co.uk )
Keywords: CT Scan, DNA, K.S. Parthasarathy, Radiation,
________________________________________
Printable version | Aug 22, 2009 8:24:48 AM | http://beta.thehindu.com/sci-tech/science/article4850.ece
Wednesday, August 12, 2009
Interview with Profesor Roger Clarke, Chairman, International Commission on Radiological Protection
EXTRACT OF THE INTERVIEW GIVEN BY Prof. Roger Clarke, chairman, International Commission on Radiological protection to Dr. K.S. Parthasarathy, Secretary, AERB during his visit to India to participate in the International Conference on Medical Physics and the XIXth annual Conference of Association of Medical Physicists of India
( Published in the AERB Newsletter)
Dr. KSP : I remember that it is not your first visit to India
Prof. Roger Clarke : I cam to India a few years ago. But I am attending the Medical Physics Conference for the first time.
KSP : In your last visit you addressed the officers of the Atomic energy Regulatory Board (AERB).
RC : I know a few colleagues from India who worked with me in the Committees of the International Commission on Radiological protection.
KSP: How did you get into the field of radiological protection? What was the incentive to enter this field? The career of a radiation physicist may not have been lucrative. Is it not?
RC : I was a reactor physicist working for the Central Electricity Generating Board (CEGB). One day my head of Division came to me. He wanted an answer for the question, with how many failed fuel plus pins you can operate an Advanced Gas Cooled Reactor (AGCR). It was in the Sixties. AGCR fuel was more expensive. Primarily the emphasis was on the basis of those to the public. I collected relevant data. In the process, I calculated the inventory of the fission products. I got introduced to health physics. I did some environmental modeling, got interest in radiobiology. Later I joined the National Radiological Protection Board to establish close assessment capability after gathering inputs on the environmental concentration of radionuclide. There was a group working on the movement of radionuclide in the biosphere. This was 20 years ago. This group was primarily interested in the study of radiation doses due to releases of radionuclide.
KSP: Historically, the International Commission on Radiological Protection (ICRP) was setup to make recommendations on the safe use of ionizing radiation in medicine. But it took a few decades for ICRP to bring out comprehensive recommendations on the protection of patients in diagnostic radiology. What was the reasons for this? Was it because ICRP did not want any control on medical radiation proactive?
RC : In the early years, therapeutic treatment was given more emphasis. The forerunner of the ICRP originated from the recommendations of the British X-ray and Radium Protection Committee. Then the major concern was protection of the workers. This was because deterministic effects such as extensive skin damage was seen among the x-ray workers who handled x-ray units. After the Second World War more penetrating radiations came to be used in medicine. Artificial radioisotopes appeared on the scene. More and More public were exposed. The emphasis shifted to public exposure. It coincided with more developments in fifties the emphasis was on therapy. Later more and more diagnostic technologies were developed.
KSP: Is it true that after the Second World War, many technically qualified people entered the job market. Many of them were electrical engineers. Apparently, this gave a boost to the development of newer technologies, which included manufacture of x-ray generations of higher and higher voltages.
RC : That is true. Radiation generators emitting more penetrating radiation began to appear in medical practice. Leukemia was identified among medical practitioners. The work by an American Physician Mr. Shields Warren is notable. He reported that Leukemia among radiologists was higher than that among general medical practitioners. It was obvious that ICRP, in this background, started giving more emphasis to patient protection. I would like to mention one recent development. Deterministic effects are coming out into focus now. Some of the interventional procedure, if carried out without care, can give substantial does to patients.
KSP: So it is not true that ICRP was somewhat biased in favour of radiologists over the years. What was the type of representation radiologists had in the ICRP?
RC: That ICRP charter states that only one radiologist need be there in ICRP though it was set up by the International Congress of Radiology – a professional association of radiologist – It is often not known that there are two more organizations to be considered, the International Commission on Radiation Units (ICRUs) and the International Committee for Education in Radiation and Radiology. The latter organization was established a few years back, but was not very active. It was re-established around five years back.
KSP: What are the new concerns?
RC: The concern of the radiologists shifted to finding out what is a better image. Future is in imaging, in medical imaging. For instance, digital imaging in interventional radiology, electronic manipulation of images, fluoroscopy with computer software. These technologies are likely to appear. More and more computer will start controlling x-ray imaging. Surgeons will turn round and expect computers to control the imaging procedure. With the newer techniques being used a dose reduction of a factor of about 10 is possible to the patient. The workers are also benefited by the dose reduction.
KSP: Do you agree that the scholarly discussion on the Linear-Non Threshold (L-NT)hypothesis has contributed to the notion that there is no safe level of radiation. Has it not sensitized the large public to greater and unreasonable levels?.
RC : I agree. When experts disagree, the credibility of specialists suffers. If experts do not agree, how can people decide which side of the argument is believable? I cannot deny that the arguments on L-NT has created some difficulties. The situation could be bad because there is an increasing possibility that decisions in science may be made by judges and juries in court rooms and not by professional association or by Royal Societies. The judiciary system may not be able to convince itself about the increased possibilities of radiation effects.
KSP: Don’t you thing that it is futile to try to get a deterministic answer to a purely probabilistic question?
RC: Yes. But I do not understand why some people wanted to establish that there is a threshold does below which there will not be any radiation effect. One of the major difficulties is in tackling the problem of old contaminated sites. Small radiation doses due to residual radio activities left behind at certain sites an cause very tiny amount of radiation doses. But when these doses are integrated over several thousand years. One may end up with getting significant amount of doses. We ill be left with the estimates of a few hundreds of probable deaths due to these collective doses accumulated over a long period of time. But I believe that we must have started dialogue on acceptable risks.
KSP : I am sure we must exclude voluntary risks such as risk due to smoking while we consider acceptable risks.
RC : Yes, I agree. Only involuntary risks are to be considered. In general, I am worried that the philosophy of protection has become somewhat complex.
KSP :Even for the professional ……..
RC : You said that and I agree. We must develop simpler concepts. ICRP must start consultations with other groups and collect ideas for reviewing and consolidating the system of protection. We have started to do that already. It explains why some of our recent documents are better than earlier ones. Consultation with others will help to improve the documents. The document on radon is an instance in point.
KSP: Everyone was keen on the on-going L-NT controversy. While the ICRP and the NRPB supported the argument that there is no threshold for the effects of ionizing radiation, the US Health Physics Society was unconvinced. The NRPB bulletin went to town with the suggestion that the attitude of the Health Physics Society is in tune with the liberalized attitude of US Administration to nuclear power. Can you comment on this development?
RC : Yes, certainly different professional groups looked at this issue very differently. American Health Physics Society has its own stated view. I have been to Health Physicists Society. Lots of people were interested in the controversy. The arguments put forth by the Health Physics Society are outdated with respect to the recent findings on the Japanese survivors of the atomic weapons. They did not then have the occasion to see the data. The recent data indicated that there could be significant risk at doses as low as 50 mSv, of course with much uncertainty. I do not still understand why they are looking for a threshold. There are many unknown cellular phenomena to be understood. Genomic instability, for instance.
KSP: You have become an unquestionable proponent of the linear non threshold theory. Certainly you didn’t ask for such a position. Do you really think that this controversy when uncontrolled?
RC: Yes. In my view, there is no need to search for a threshold. Nobody denies that there is evidence for the repair of cellular damage. But we cannot ignore that the repair mechanisms are also statistical in nature.
KSP: Biological effects of radiation has been studied for the past 100 years. The stochastic effects such as cancer world not have even been through about, but for the long an expensive epidemiological studies. Is it not unfair to spend too much of resources, in fact, vast sums of money to carry out studies about an agent which is now known to be much less hazardous than hundreds of toxic chemicals about which practically nothing is known.
RC: I may say that physicists should take the blame for it. The study of nuclear physics progressed rapidly. Some of the best brains entered the profession. The study of physics was intellectually satisfying and scientifically stimulating. Unfortunately, the same was not true for chemicals. Of late, biologists are also stating to use more and more mathematical formulations. Probably natural sciences are getting ready to make quantitative estimate.
The biggest injustice done is to attach a speaker to a Geiger counter, You must remember that nobody attaches a speaker to a gas chromatograph. In case higher values of hazardous chemicals are detected, the speaker howling is more dramatic and will definitely arrest the attention and create a problem.
There are several aspects to the understanding of the risks from chemical compared to the risks from chemical radiation. Natural radiation is present everywhere. There is no such analogue in the case of hazardous chemicals. Releasing genetically modified plants without control is probably in my view a higher problem. No doubt of course, this area getting more attention now.
KSP When the French Academy if Sciences published a report critical of ICRP for lowering dose it as French Government policy. To many, it was not surprising as France has a stake in nuclear power. They feel that lower dose limit is probably not in this interest. What is the current position of the French Government?
RC: The French Government has signed the European Directive. The French Electric Power Industry is committed to ICRP recommendations.
KSP: Release form a nuclear facility can be controlled by appropriate methods. It may cause increase in the collective doses to workers. In some instances the collective doses to workers may be far more than those to public. Which option will be acceptable in your opinion?
RC: Both occupational and public exposures are being reduced by optimization procedures. Storage of waste on-site may actually cause a potential for accidental exposure of the public as well as exposing workers. As long as individual doses – workers and public – are acceptably low, the situation is optimized.
KSP: The recommendation of ICRP are universally respected. I remember that the National Radiological Protection Board recommended a dose limit of 15 mSv/year even before ICRP recommendation were issued. NRPB faced some amount of criticism. What is the status of implementation in the UK and USA?
RC: The European directive was issued in May1996. These directives are legally binding on all states and the directives were to be implemented by 2000. In UK, the Health and Safety Executive has to make appropriate already been started. There is a need for harmonizing different documents. For instance different exemption levels are given under different contexts in Europe.
KSP: why are there such differences in exemption levels in Europe?
RC: In UK, the Radioactive Substances Act is one of the regulations which is different from The lionizing Radiation Regulation 1985. Health and Safety Executive is reviewing both these. The disposal of radioactive substances comes under the Radioactive Substances Act. The harmonizing of values and concepts and making them consistent is taking some time.
KSP: Was it not because there are some differences in opinions and views?
RC: That is not the reason. Certainly different agencies are at work. Most of the values of exemption levels are given in the European Directives.
KSP: Based on the impression that ICRP may revise the dose limits downward, AERB had its first comprehensive review of occupational exposures in 1989, a year before ICRP 60 was issued. We have implemented the recommendations are similar to those of ICRP except that the maximum dose limit in any year recommended by AERB is 30 mSv instead of 50 mSv recommended by ICRP.
Our experience is that among the various groups using ionizing radiation, industrial radiography is the most important. In India this field is probably one of the most regulated. The Regulatory Board issue authorization only if certified radiographers, a site-in-charge and appropriate radiation measuring instruments and protective accessories are available at every site.
RC: Industrial radiography has certain peculiarities. In this field, the workers are likely to be exposed to high radiation doses. The field has more potential for accidental exposures. I understand that ionizing radiation occurred in the field of industrial radiography. A man whose film badges did not record any reading but did due to radiation exposure related symptoms.
KSP: He must have been totally careless. I remember that the dose to this worker was evaluated by very advanced dosimeter method using his teeth as sample. What do you propose to make this field safer?
RC: This field is such that it is impossible to supervise them well, as their place of work is distributed in various work environments. For instance, often they work alone in the field while laying gas pipelines. So the only way we can improve the safety status in by imparting appropriate training to the workers. The regulatory organisation should ensure that such dedicated training programme is extended to all the workers.
KPS: Since reducing dose in medical X-ray practice is easier and less expensive, is it not more appropriate to allocate resources more prudently to achieve substantial reduction in collective doses in diagnostic radiology? If I say that there should be more efforts to reduce needless medical exposures, it may be looked upon as an attempt to divert public opinion from exposures in nuclear installation. ICRP should come out with such clear statements on avoiding needless exposure.
RC: We have gone a long way. The International Basic Safety for Protection against Radiation and safety of Radiation Sources has given certain guidance values. The United Kingdom also accepted certain guidelines. With these precautions, the collective dose can be reduced by about 40% But this was more than offset by the predominant use of CT scan units.
KSP: When many States in the US brought out guidelines for typical X-ray examination based on the National X-ray Trend Programmes, UK was less enthusiastic about the concept. Now Basic Safety Standards came out with guidance. What is your general view on this? Can you include the guidance levels in regulation?
RC: I believe that prescribing guidance levels similar to the one stated in BSS is in the right direction. The experience in the UK has been that there has been substantial reduction in collective doses to population at large over the year.
KSP: In your lecture at the International Conference on Medical Physics you spoke about carrying out appropriate evaluation of dose to commercial airline workers under the category of occupational workers. How many countries in Europe have done this?
RC: Cosmic rays obviously come under natural radiation. Under the European law, the member states shall undertake surveys to estimate the magnitude of the radiation exposure due to natural radiation. Currently large groups of persons journey by commercially operated airlines. Because of this, exposure to sensitive groups such as pregnant women may also have to be considered. There is a general thinking that dose contribution to the crew of commercial airline should be quantified by appropriate methods. This cab be done by on-board instrumentation and by considering the number of hours of flying by the airline. The intention is not that all the crew must wear dosimeters but the measurement of exposure will have to be carried out systematically.
KSP: At such high altitudes, the primary component of cosmic rays are high energy protons and neutrons. This is probably one area where we cannot do much about source control. What we can do is that regulated the exposure and the altitude in which the airline flies. The probability of radiation hitting the embryo or foetus will be miniscule. What is your thinking?
RC: I must say that currently the air crew are not subject to dose limits. But the radiation dose should be measured reasonably accurately by asking the number of hours the crew has flown and also by ascertaining the route of travel.
KSP: I understand that the Concord has appropriate monitoring equipment on board way back in 1970. When I was attending the Congress of international Radiation Protection Association at Brighton, I was at the dinner table with a group of scientist from UK who were actually making measurements in the Concord. Have you carried out systematic measurements? Is there anything new published since the special issue of “Radiation Protection Dosimetry” journal was published?
RC: Yes. Radiation measurements have been done and date are available.
KSP: I thought that the exposure is significant only during solar flares.
RC: According to my information the radiation levels on no occasion has increased to such an extent during the past 20 years which led to reducing the altitude of the aircraft to get the benefit of atmospheric shielding.
KSP: ICRP recommendation on pregnant women is known to be too conservative. What was the background information? Was there any re-thinking on this? As the dose limit recommended is different to measure, many institution may decide to withdraw pregnant women from radiation work. I understand that the topic is widely discussed in countries such as Canada where a great proportion of medical radiation workers are women.
RC: ICRP considers that the basis for the control of occupational exposure of women who are not pregnant is the same as that for men. On the other hand if a women is or may pregnant there is a need for additional controls to be considered to protect the unborn child. The considered is at times more prone than the post-natal individual to deterministic injuries caused by radiation and may be more sensitive to the induction of later deterministic effects in the live-born child including significant mental retardation will not happen if the exposure of the mother dose not exceed the dose limits now recommended for occupation exposure regardless of the distribution of the exposure over time.
Accidental high exposure of the mother may be more damaging to the concepts than to the mother.
The commission’s policy us that the methods of protection at work for women who may be pregnant should provide a standard of protection for any concepts broadly comparable with that provided for members of the general public. The commission considers that its policy will be adequately applied if the mother is exposed prior to the declaration of pregnancy under the system of protection recommended by the commission including the recommended dose limits for occupational exposure. This is the basis on which the commission recommended that no special occupational dose limits is needed for women in general.
The ICRP thought the recommendation of 2 mSv measured over the abdomen of a pregnant woman for the entire gestation period is very helpful. But there is some feeling that it is very restrictive.
KSP: In fact in Canada Atomic Energy Control Board (AECB) arranged discussion with woman workers in eight cities and asked for views. A few hundred women participated. Many of them argued that there is no reason to change the earlier limit of 10mSv.
RC: The Commission no longer recommends a dose limit of 2 mSv during the gestation period as measured on the abdomen of the pregnant women. The ICRP publication number 75 describes the current ICRP recommendation. Overall risks associated with radiation exposure of men and women are broadly similar. ICRP now sees no need to make any distinction between the two sexes in the control of occupational exposure. But once a worked is known to be pregnant, ICRP recommends higher standard of protection for the concepts.
The advice given in publication No.60 has been interpreted too rigidly. ICRP now recommends that the working conditions of a pregnant worker after the declaration of pregnancy, should be such as to make it unlikely that the addition equivalent dose to the concepts will exceed about one mSv during the remainder of the pregnancy.
It is important to highlight the responsibility of the worker and employer to meet the Commission’s objective. The pregnant worker should declare her pregnancy promptly to the management. The management should then organize the working conditions to make it unlikely that the additional equivalent dose to the concepts will exceed about one mSv during the remainder of the pregnancy.
KSP: Atomic Energy Control Board of Canada had detailed consultations with women groups on the reco0mmendation. I understand they may now recommend an external dose limit of 4 mSv on the abdomen or an intake of 20 percent of the annual limit if intake. ACEB had compared the general risks to the foetus during pregnancy and showed that at 4 mSv it is very low indeed. What is your view on this approach? I feel that if ICRP’s view expressed in publication No.75 is accepted, many employers will discriminate against women being employed in radiation work.
RC: The ICRP position is essentially as it was in publication 60 and elaborated in publication 75. The foetus to be protected broadly as though it were a member of the public.
KSP: Though conceptually it is clear that exposure at the dose limit is just tolerable, exposing everyone to the dose limit all the tome is not acceptable. Was it not more appropriate for ICRP to recommend a range of values rather than a single value?
RC: The current dose limit of 20 mSv per year average for 5 years offers this operational flexibility. A single number is administratively convenient. It is obvious that the body dies not known whether the exposure occurred in one calendar year or another. Biology does not identify this.
KSP: The recommendations of ICRP are scientifically the best available. But you will agree with me that these recommendation have enormous social impact. Is it justifiable for over a dozen specialists in purely scientific disciplines to take such decisions which have enormous social impact? Don’t you think that the representation in ICRP should be broadened to include social scientists and economists?
RC: There are various components to this question. ICRP recommendations reflect the best scientific information. We do not say what is acceptable to society or not. There is one recent development. ICRP is currently engaged in more and more consultations with specialists by providing drafts of their recommendations to other specialists and concerned people for review. It would certainly reveal whether there is any inconsistency in the concept and approach put forward by ICRP. It will help to find out whether there is any fallacy in our approach. I believe the recent ICRP document bear testimony to this.
( Published in the AERB Newsletter)
Dr. KSP : I remember that it is not your first visit to India
Prof. Roger Clarke : I cam to India a few years ago. But I am attending the Medical Physics Conference for the first time.
KSP : In your last visit you addressed the officers of the Atomic energy Regulatory Board (AERB).
RC : I know a few colleagues from India who worked with me in the Committees of the International Commission on Radiological protection.
KSP: How did you get into the field of radiological protection? What was the incentive to enter this field? The career of a radiation physicist may not have been lucrative. Is it not?
RC : I was a reactor physicist working for the Central Electricity Generating Board (CEGB). One day my head of Division came to me. He wanted an answer for the question, with how many failed fuel plus pins you can operate an Advanced Gas Cooled Reactor (AGCR). It was in the Sixties. AGCR fuel was more expensive. Primarily the emphasis was on the basis of those to the public. I collected relevant data. In the process, I calculated the inventory of the fission products. I got introduced to health physics. I did some environmental modeling, got interest in radiobiology. Later I joined the National Radiological Protection Board to establish close assessment capability after gathering inputs on the environmental concentration of radionuclide. There was a group working on the movement of radionuclide in the biosphere. This was 20 years ago. This group was primarily interested in the study of radiation doses due to releases of radionuclide.
KSP: Historically, the International Commission on Radiological Protection (ICRP) was setup to make recommendations on the safe use of ionizing radiation in medicine. But it took a few decades for ICRP to bring out comprehensive recommendations on the protection of patients in diagnostic radiology. What was the reasons for this? Was it because ICRP did not want any control on medical radiation proactive?
RC : In the early years, therapeutic treatment was given more emphasis. The forerunner of the ICRP originated from the recommendations of the British X-ray and Radium Protection Committee. Then the major concern was protection of the workers. This was because deterministic effects such as extensive skin damage was seen among the x-ray workers who handled x-ray units. After the Second World War more penetrating radiations came to be used in medicine. Artificial radioisotopes appeared on the scene. More and More public were exposed. The emphasis shifted to public exposure. It coincided with more developments in fifties the emphasis was on therapy. Later more and more diagnostic technologies were developed.
KSP: Is it true that after the Second World War, many technically qualified people entered the job market. Many of them were electrical engineers. Apparently, this gave a boost to the development of newer technologies, which included manufacture of x-ray generations of higher and higher voltages.
RC : That is true. Radiation generators emitting more penetrating radiation began to appear in medical practice. Leukemia was identified among medical practitioners. The work by an American Physician Mr. Shields Warren is notable. He reported that Leukemia among radiologists was higher than that among general medical practitioners. It was obvious that ICRP, in this background, started giving more emphasis to patient protection. I would like to mention one recent development. Deterministic effects are coming out into focus now. Some of the interventional procedure, if carried out without care, can give substantial does to patients.
KSP: So it is not true that ICRP was somewhat biased in favour of radiologists over the years. What was the type of representation radiologists had in the ICRP?
RC: That ICRP charter states that only one radiologist need be there in ICRP though it was set up by the International Congress of Radiology – a professional association of radiologist – It is often not known that there are two more organizations to be considered, the International Commission on Radiation Units (ICRUs) and the International Committee for Education in Radiation and Radiology. The latter organization was established a few years back, but was not very active. It was re-established around five years back.
KSP: What are the new concerns?
RC: The concern of the radiologists shifted to finding out what is a better image. Future is in imaging, in medical imaging. For instance, digital imaging in interventional radiology, electronic manipulation of images, fluoroscopy with computer software. These technologies are likely to appear. More and more computer will start controlling x-ray imaging. Surgeons will turn round and expect computers to control the imaging procedure. With the newer techniques being used a dose reduction of a factor of about 10 is possible to the patient. The workers are also benefited by the dose reduction.
KSP: Do you agree that the scholarly discussion on the Linear-Non Threshold (L-NT)hypothesis has contributed to the notion that there is no safe level of radiation. Has it not sensitized the large public to greater and unreasonable levels?.
RC : I agree. When experts disagree, the credibility of specialists suffers. If experts do not agree, how can people decide which side of the argument is believable? I cannot deny that the arguments on L-NT has created some difficulties. The situation could be bad because there is an increasing possibility that decisions in science may be made by judges and juries in court rooms and not by professional association or by Royal Societies. The judiciary system may not be able to convince itself about the increased possibilities of radiation effects.
KSP: Don’t you thing that it is futile to try to get a deterministic answer to a purely probabilistic question?
RC: Yes. But I do not understand why some people wanted to establish that there is a threshold does below which there will not be any radiation effect. One of the major difficulties is in tackling the problem of old contaminated sites. Small radiation doses due to residual radio activities left behind at certain sites an cause very tiny amount of radiation doses. But when these doses are integrated over several thousand years. One may end up with getting significant amount of doses. We ill be left with the estimates of a few hundreds of probable deaths due to these collective doses accumulated over a long period of time. But I believe that we must have started dialogue on acceptable risks.
KSP : I am sure we must exclude voluntary risks such as risk due to smoking while we consider acceptable risks.
RC : Yes, I agree. Only involuntary risks are to be considered. In general, I am worried that the philosophy of protection has become somewhat complex.
KSP :Even for the professional ……..
RC : You said that and I agree. We must develop simpler concepts. ICRP must start consultations with other groups and collect ideas for reviewing and consolidating the system of protection. We have started to do that already. It explains why some of our recent documents are better than earlier ones. Consultation with others will help to improve the documents. The document on radon is an instance in point.
KSP: Everyone was keen on the on-going L-NT controversy. While the ICRP and the NRPB supported the argument that there is no threshold for the effects of ionizing radiation, the US Health Physics Society was unconvinced. The NRPB bulletin went to town with the suggestion that the attitude of the Health Physics Society is in tune with the liberalized attitude of US Administration to nuclear power. Can you comment on this development?
RC : Yes, certainly different professional groups looked at this issue very differently. American Health Physics Society has its own stated view. I have been to Health Physicists Society. Lots of people were interested in the controversy. The arguments put forth by the Health Physics Society are outdated with respect to the recent findings on the Japanese survivors of the atomic weapons. They did not then have the occasion to see the data. The recent data indicated that there could be significant risk at doses as low as 50 mSv, of course with much uncertainty. I do not still understand why they are looking for a threshold. There are many unknown cellular phenomena to be understood. Genomic instability, for instance.
KSP: You have become an unquestionable proponent of the linear non threshold theory. Certainly you didn’t ask for such a position. Do you really think that this controversy when uncontrolled?
RC: Yes. In my view, there is no need to search for a threshold. Nobody denies that there is evidence for the repair of cellular damage. But we cannot ignore that the repair mechanisms are also statistical in nature.
KSP: Biological effects of radiation has been studied for the past 100 years. The stochastic effects such as cancer world not have even been through about, but for the long an expensive epidemiological studies. Is it not unfair to spend too much of resources, in fact, vast sums of money to carry out studies about an agent which is now known to be much less hazardous than hundreds of toxic chemicals about which practically nothing is known.
RC: I may say that physicists should take the blame for it. The study of nuclear physics progressed rapidly. Some of the best brains entered the profession. The study of physics was intellectually satisfying and scientifically stimulating. Unfortunately, the same was not true for chemicals. Of late, biologists are also stating to use more and more mathematical formulations. Probably natural sciences are getting ready to make quantitative estimate.
The biggest injustice done is to attach a speaker to a Geiger counter, You must remember that nobody attaches a speaker to a gas chromatograph. In case higher values of hazardous chemicals are detected, the speaker howling is more dramatic and will definitely arrest the attention and create a problem.
There are several aspects to the understanding of the risks from chemical compared to the risks from chemical radiation. Natural radiation is present everywhere. There is no such analogue in the case of hazardous chemicals. Releasing genetically modified plants without control is probably in my view a higher problem. No doubt of course, this area getting more attention now.
KSP When the French Academy if Sciences published a report critical of ICRP for lowering dose it as French Government policy. To many, it was not surprising as France has a stake in nuclear power. They feel that lower dose limit is probably not in this interest. What is the current position of the French Government?
RC: The French Government has signed the European Directive. The French Electric Power Industry is committed to ICRP recommendations.
KSP: Release form a nuclear facility can be controlled by appropriate methods. It may cause increase in the collective doses to workers. In some instances the collective doses to workers may be far more than those to public. Which option will be acceptable in your opinion?
RC: Both occupational and public exposures are being reduced by optimization procedures. Storage of waste on-site may actually cause a potential for accidental exposure of the public as well as exposing workers. As long as individual doses – workers and public – are acceptably low, the situation is optimized.
KSP: The recommendation of ICRP are universally respected. I remember that the National Radiological Protection Board recommended a dose limit of 15 mSv/year even before ICRP recommendation were issued. NRPB faced some amount of criticism. What is the status of implementation in the UK and USA?
RC: The European directive was issued in May1996. These directives are legally binding on all states and the directives were to be implemented by 2000. In UK, the Health and Safety Executive has to make appropriate already been started. There is a need for harmonizing different documents. For instance different exemption levels are given under different contexts in Europe.
KSP: why are there such differences in exemption levels in Europe?
RC: In UK, the Radioactive Substances Act is one of the regulations which is different from The lionizing Radiation Regulation 1985. Health and Safety Executive is reviewing both these. The disposal of radioactive substances comes under the Radioactive Substances Act. The harmonizing of values and concepts and making them consistent is taking some time.
KSP: Was it not because there are some differences in opinions and views?
RC: That is not the reason. Certainly different agencies are at work. Most of the values of exemption levels are given in the European Directives.
KSP: Based on the impression that ICRP may revise the dose limits downward, AERB had its first comprehensive review of occupational exposures in 1989, a year before ICRP 60 was issued. We have implemented the recommendations are similar to those of ICRP except that the maximum dose limit in any year recommended by AERB is 30 mSv instead of 50 mSv recommended by ICRP.
Our experience is that among the various groups using ionizing radiation, industrial radiography is the most important. In India this field is probably one of the most regulated. The Regulatory Board issue authorization only if certified radiographers, a site-in-charge and appropriate radiation measuring instruments and protective accessories are available at every site.
RC: Industrial radiography has certain peculiarities. In this field, the workers are likely to be exposed to high radiation doses. The field has more potential for accidental exposures. I understand that ionizing radiation occurred in the field of industrial radiography. A man whose film badges did not record any reading but did due to radiation exposure related symptoms.
KSP: He must have been totally careless. I remember that the dose to this worker was evaluated by very advanced dosimeter method using his teeth as sample. What do you propose to make this field safer?
RC: This field is such that it is impossible to supervise them well, as their place of work is distributed in various work environments. For instance, often they work alone in the field while laying gas pipelines. So the only way we can improve the safety status in by imparting appropriate training to the workers. The regulatory organisation should ensure that such dedicated training programme is extended to all the workers.
KPS: Since reducing dose in medical X-ray practice is easier and less expensive, is it not more appropriate to allocate resources more prudently to achieve substantial reduction in collective doses in diagnostic radiology? If I say that there should be more efforts to reduce needless medical exposures, it may be looked upon as an attempt to divert public opinion from exposures in nuclear installation. ICRP should come out with such clear statements on avoiding needless exposure.
RC: We have gone a long way. The International Basic Safety for Protection against Radiation and safety of Radiation Sources has given certain guidance values. The United Kingdom also accepted certain guidelines. With these precautions, the collective dose can be reduced by about 40% But this was more than offset by the predominant use of CT scan units.
KSP: When many States in the US brought out guidelines for typical X-ray examination based on the National X-ray Trend Programmes, UK was less enthusiastic about the concept. Now Basic Safety Standards came out with guidance. What is your general view on this? Can you include the guidance levels in regulation?
RC: I believe that prescribing guidance levels similar to the one stated in BSS is in the right direction. The experience in the UK has been that there has been substantial reduction in collective doses to population at large over the year.
KSP: In your lecture at the International Conference on Medical Physics you spoke about carrying out appropriate evaluation of dose to commercial airline workers under the category of occupational workers. How many countries in Europe have done this?
RC: Cosmic rays obviously come under natural radiation. Under the European law, the member states shall undertake surveys to estimate the magnitude of the radiation exposure due to natural radiation. Currently large groups of persons journey by commercially operated airlines. Because of this, exposure to sensitive groups such as pregnant women may also have to be considered. There is a general thinking that dose contribution to the crew of commercial airline should be quantified by appropriate methods. This cab be done by on-board instrumentation and by considering the number of hours of flying by the airline. The intention is not that all the crew must wear dosimeters but the measurement of exposure will have to be carried out systematically.
KSP: At such high altitudes, the primary component of cosmic rays are high energy protons and neutrons. This is probably one area where we cannot do much about source control. What we can do is that regulated the exposure and the altitude in which the airline flies. The probability of radiation hitting the embryo or foetus will be miniscule. What is your thinking?
RC: I must say that currently the air crew are not subject to dose limits. But the radiation dose should be measured reasonably accurately by asking the number of hours the crew has flown and also by ascertaining the route of travel.
KSP: I understand that the Concord has appropriate monitoring equipment on board way back in 1970. When I was attending the Congress of international Radiation Protection Association at Brighton, I was at the dinner table with a group of scientist from UK who were actually making measurements in the Concord. Have you carried out systematic measurements? Is there anything new published since the special issue of “Radiation Protection Dosimetry” journal was published?
RC: Yes. Radiation measurements have been done and date are available.
KSP: I thought that the exposure is significant only during solar flares.
RC: According to my information the radiation levels on no occasion has increased to such an extent during the past 20 years which led to reducing the altitude of the aircraft to get the benefit of atmospheric shielding.
KSP: ICRP recommendation on pregnant women is known to be too conservative. What was the background information? Was there any re-thinking on this? As the dose limit recommended is different to measure, many institution may decide to withdraw pregnant women from radiation work. I understand that the topic is widely discussed in countries such as Canada where a great proportion of medical radiation workers are women.
RC: ICRP considers that the basis for the control of occupational exposure of women who are not pregnant is the same as that for men. On the other hand if a women is or may pregnant there is a need for additional controls to be considered to protect the unborn child. The considered is at times more prone than the post-natal individual to deterministic injuries caused by radiation and may be more sensitive to the induction of later deterministic effects in the live-born child including significant mental retardation will not happen if the exposure of the mother dose not exceed the dose limits now recommended for occupation exposure regardless of the distribution of the exposure over time.
Accidental high exposure of the mother may be more damaging to the concepts than to the mother.
The commission’s policy us that the methods of protection at work for women who may be pregnant should provide a standard of protection for any concepts broadly comparable with that provided for members of the general public. The commission considers that its policy will be adequately applied if the mother is exposed prior to the declaration of pregnancy under the system of protection recommended by the commission including the recommended dose limits for occupational exposure. This is the basis on which the commission recommended that no special occupational dose limits is needed for women in general.
The ICRP thought the recommendation of 2 mSv measured over the abdomen of a pregnant woman for the entire gestation period is very helpful. But there is some feeling that it is very restrictive.
KSP: In fact in Canada Atomic Energy Control Board (AECB) arranged discussion with woman workers in eight cities and asked for views. A few hundred women participated. Many of them argued that there is no reason to change the earlier limit of 10mSv.
RC: The Commission no longer recommends a dose limit of 2 mSv during the gestation period as measured on the abdomen of the pregnant women. The ICRP publication number 75 describes the current ICRP recommendation. Overall risks associated with radiation exposure of men and women are broadly similar. ICRP now sees no need to make any distinction between the two sexes in the control of occupational exposure. But once a worked is known to be pregnant, ICRP recommends higher standard of protection for the concepts.
The advice given in publication No.60 has been interpreted too rigidly. ICRP now recommends that the working conditions of a pregnant worker after the declaration of pregnancy, should be such as to make it unlikely that the addition equivalent dose to the concepts will exceed about one mSv during the remainder of the pregnancy.
It is important to highlight the responsibility of the worker and employer to meet the Commission’s objective. The pregnant worker should declare her pregnancy promptly to the management. The management should then organize the working conditions to make it unlikely that the additional equivalent dose to the concepts will exceed about one mSv during the remainder of the pregnancy.
KSP: Atomic Energy Control Board of Canada had detailed consultations with women groups on the reco0mmendation. I understand they may now recommend an external dose limit of 4 mSv on the abdomen or an intake of 20 percent of the annual limit if intake. ACEB had compared the general risks to the foetus during pregnancy and showed that at 4 mSv it is very low indeed. What is your view on this approach? I feel that if ICRP’s view expressed in publication No.75 is accepted, many employers will discriminate against women being employed in radiation work.
RC: The ICRP position is essentially as it was in publication 60 and elaborated in publication 75. The foetus to be protected broadly as though it were a member of the public.
KSP: Though conceptually it is clear that exposure at the dose limit is just tolerable, exposing everyone to the dose limit all the tome is not acceptable. Was it not more appropriate for ICRP to recommend a range of values rather than a single value?
RC: The current dose limit of 20 mSv per year average for 5 years offers this operational flexibility. A single number is administratively convenient. It is obvious that the body dies not known whether the exposure occurred in one calendar year or another. Biology does not identify this.
KSP: The recommendations of ICRP are scientifically the best available. But you will agree with me that these recommendation have enormous social impact. Is it justifiable for over a dozen specialists in purely scientific disciplines to take such decisions which have enormous social impact? Don’t you think that the representation in ICRP should be broadened to include social scientists and economists?
RC: There are various components to this question. ICRP recommendations reflect the best scientific information. We do not say what is acceptable to society or not. There is one recent development. ICRP is currently engaged in more and more consultations with specialists by providing drafts of their recommendations to other specialists and concerned people for review. It would certainly reveal whether there is any inconsistency in the concept and approach put forward by ICRP. It will help to find out whether there is any fallacy in our approach. I believe the recent ICRP document bear testimony to this.
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