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.

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
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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

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