'Neutron bomb capability exists'

Print edition : December 09, 2000
Interview with Dr. Anil Kakodkar.

Dr. Anil Kakodkar took charge as Chairman, Atomic Energy Commission, and Secretary, Department of Atomic Energy (DAE), on December 1. This former Director of the Bhabha Atomic Research Centre (BARC), Trombay, succeeded Dr. R. Chidambaram to these posts. Dr. Kakodkar, 57, obtained a B.E. degree in mechanical engineering from Bombay University and an M.Sc. from Nottingham University in the U.K. In 1963-64 he underwent training in nuclear science and technology with the then Atomic Energy Establishm ent, Trombay. Associated with research and development related to nuclear reactors since 1964, he was involved in India's first Peaceful Nuclear Explosion (PNE) experiment of May 1974. He played an important role in the five nuclear tests conducted in Ma y 1998. He played a key role in the design and construction of Dhruva, the 100 MW high flux reactor at Trombay and the development of indigenous Pressurised Heavy Water Reactor (PHWR) system. His work in the rehabilitation of the two reactors at Kalpakkam and the first unit at Rawatbhatta, which at one stage were on the verge of being written off, are examples of his engineering capability. He has built teams of specialised engineers and scientists in the reactor engineering programm e. His dream project is to build the Advanced Heavy Water Reactor (AHWR) that uses thorium-uranium 233 as primary energy source with plutonium as the driver fuel. The unique reactor system, with simplified but safe technology, will generate 75 per cent o f electricity from thorium.

SHASHI ASHIWAL

T.S. Subramanian met Dr. Kakodkar for an interview at Trombay. Excerpts:

You have stated that India's nuclear energy programme has come of age. Could you elaborate on this?

Any research and development (R&D) programme must ultimately lead to technological benefit to the society. In our atomic energy programme, as a result of the R&D that has been done at the Bhabha Atomic Research Centre (BARC) and other institutions, and R &D contributions from industry in manufacturing technology, we have today the PHWR programme which is in a successful commercial domain. We are able to build our own nuclear power reactors, manufacture all the essential nuclear inputs such as heavy water , zirconium alloy components and nuclear fuel. The PHWRs are operating at a high capacity factor. The Nuclear Power Corporation of India Limited has been making considerable profits. It is a demonstration of the successful migration of technology from th e laboratory to the industry. So there is a degree of maturity in the DAE.

Obviously, if the nuclear power programme has to grow, there should be more and more PHWRs, with larger unit sizes too. Right now we are building 220 MW PHWRs. At Tarapur we have started construction of 500 MW PHWRs. We should take up more reactors for c onstruction and the 500 MW reactor programme should get considerable acceleration.

This programme is no longer limited by technology. It is a question of creating more investments, and more projects, and megawatt capacity would follow. This is important because nuclear electricity generation today forms only a low fraction of the total electricity generated in the country. We should take it to a reasonably higher fraction because this is a future energy source. Once we take the nuclear power capacity (generation) to 7,000 or 8,000 MWe level, the internal surplus generation will be abl e to support a substantial capacity-building programme. We must have a programme where work is going on simultaneosuly at several sites. Also the technology development to support the PHWR programme has to continue because the technology is never static.

Will the construction of the 500 MW Prototype Fast Breeder Reactor (PFBR) begin at Kalpakkam soon?

We are almost ready. The second stage of our nuclear power programme, that is, the construction of the Fast Breeder Reactors (FBRs), should reach a commercial deployment stage as we have with the first stage PHWRs today. This is the key to exploiting the full potential of our nuclear energy resources and enlarging the nuclear power generation capacity. The Fast Breeder Test Reactor (FBTR) at Kalpakkam has done extremely well and all its technological objectives have been met. The Indira Gandhi Centre fo r Atomic Research (IGCAR) at Kalpakkam has done a lot of technological development work in building the full-size components for the PFBR. So they are poised to take up the construction of the PFBR. On the basis of that experience, we should be in a posi tion to start construction of a series of FBRs in India. This will be the second stage of our nuclear electricity programme.

As the FBR programme starts, we have to think of further advancement in terms of faster doubling time. The PFBR will constitute the reactor technology and we have to advance in fuel cycle technology. That is a major programme which will go on for some ti me at the IGCAR.

The third stage of our nuclear electricity programme will use thorium as fuel. Here also there will be several stages of evolutions in the thorium utilisation programme. The ultimate objective of this will be to build a pure thorium-uranium 233 based rea ctor. The AHWRs will form only the first phase of the third stage. The idea here is that we should move towards thorium utilisation on a very substantial scale, using the heavy water technology that we have. The AHWR is designed to get a large fraction o f energy output from thorium. It incorporates several advanced safety features which characterise innovative reactor designs worldwide.

What are the technological challenges that you will have to overcome in building AHWRs?

The main objective of the AHWRs is to achieve a larger degree of safety through the use of what is known as passive safety systems. For example, with, natural circulation of water, safety is no longer dependent on active components such as pumps, which m ay fail. Passive systems depend on physical principles and you thus get a large safety advantage.

In the AHWR, energy extraction from the core is through passive means. Residual heat removal is through passive means. Containment heat removal and containment circulation are both by passive means. There are several other such features.

The AHWR would be economically advantageous too. We are building into it features which will lower its capital cost. This is because there is no active equipment, or there are just one or two, which require nuclear classification. We have eliminated most of the costly equipment that require nuclear classification.

You do require some active components to back up, but they are all conventional equipment. You can buy them in the market and they are cheap. Using factory assembled coolant channels, we expect to do the coolant channel replacement work quite fast. In on e normal shutdown of the reactor, you can replace the coolant channels. This is the kind of capability we are trying to build. This is the second objective.

The third and the most important objective is to demonstrate large-scale generation of electricity from thorium. So the reactor will be in a self-sustaining mode as far as the uranium 233-thorium cycle is concerned. Whatever uranium-233 is consumed for e lectricity generation, the same amount of uranium-233 will be produced in the reactor. Of course it will require a certain amount of plutonium as a kind of driver fuel. That is why it (the AHWR) forms the first phase of the third stage...

We are defining the road map for shaping the third stage. There are several elements in it: the technologies that will go into the uranium-233 fuel cycle, that is, the fuel cycle technology; the reactor technology, and so on. For some time, the FBRs and the thorium reactors will be in a tandem mode. You breed fuel and you support more thorium capacity. Afterwards it will go into pure thorium mode.

While this is going on, we probably have to look for technologies that will make the third stage more efficient. There is a possibility that accelerator driven sub-critical systems can achieve that objective.

Are breeder reactors relevant when people talk about accelerator driven sub-critical systems?

Breeder reactors are more relevant in the sense that the technology development for them is way ahead of the technology development for accelerator driven systems...

In the accelerator driven systems, the advantage is that you get a variety of characteristics. Conceptually, it is a variation of the AHWR core coupled with a fast driver core and spallation source driven by an accelerator. We can, on the one side, have a thorium-uranium 233 fuel cycle with better doubling time. On the other side, we can incinerate the long-lived waste in the same system. So it will become a kind of self-consistent system where you can breed more fuel than you consume and incinerate mos t of the long-lived waste. This is a major advantage... This is an area where a lot of work is required to be done for a long time, for 15 to 20 years. This is a major technological challenge which is important for us. This is factored into our strategy for shaping the third stage of our nuclear power programme of thorium utilisation.

What will be the scale of import of light water reactors to reach the goal of generating 20,000 MW of nuclear electricity by 2020? Russia's Deputy Minister for Atomic Energy E.A. Reshetnikov who visited the Rajasthan Atomic Power Station in September was keen to sell six VVER-1000 reactors to India including two that are to be built at Kudankulam. Will India buy light water reactors from France or Canada?

The share of nuclear electricity in the overall electricity generation in the country should go up. Nuclear power technology is environmentally very benign. It does not emit greenhouse gases. It is a source of bulk power generation and thus there is a ne ed to increase its share. From that point of view, the imported systems are welcome as an additionality over and above the domestic programme. At this moment it will be difficult for me to say how many they will be... We can accommodate a fairly large sh are of such capacity. For example, accommodating 6,000 MWe or 7,000 MWe of light water reactor capacity or even more should not be a problem. As far as we are concerned, we will welcome it then.

Why have no new sites been identified for building PHWRs ? Why are PHWRs being bunched at the existing sites?

There is a committee looking at probable sites. The important consideration is that if there is a site, depending on its chacteristics, it can accommodate a certain capacity. So we must make full use of that site's potential. If you put multiple units at the same site, you get economic advantage. That is why we are adding more units at the same site. But there are sites which have been looked at in the past. It is necessary to look at all of them again in the present context because we have to see what are the conditions that obtain today, and also identify new sites. At the moment it appears to me that it is more urgent for us to open new projects at the existing sites. While we do that, we should define additional sites where work can be taken up in future.

Have we reprocessed enough plutonium to operate the planned FBRs?

We have to adjust the reprocessing capacity in tune with the requirements of the FBR programme. As the requirements increase, we will increase the reprocessing capacity. I don't envisage any serious problem on this front.

The three sub-kiloton nuclear devices that India exploded at Pokhran in May 1998 have given the country the capability to do sub-critical tests. Are any sub-critical tests planned?

That really depends on the government's decision. As far as R&D work is concerned, it is an ongoing process.

Are facilities in place to conduct sub-critical tests ?

No comment.

What led to the nuclear tests of May 1998? Was it because India could not keep the nuclear option open indefinitely? Was it because the Comprehensive Test Ban Treaty was to be wrapped up, and there would be pressure on India to accede to the CTBT? Wa s there pressure from the nuclear scientists in the country to go for the tests?

No, no. The question is... The scientific community has to respond to national needs. So once the decision was made, it was implemented. The fact is that it was well known that nuclear weapons existed in our neighbourhood, and also the way the CTBT discu ssions went on... there was a deadline. So it was perhaps necessary, essential for national security requirements, that this option was exercised. That is what must have been at the back of the government's decision.

How advanced is India in the matter of nuclear weaponisation? A former Chairman of the Atomic Energy Commission, Dr.P.K. Iyengar, says that the process of weaponisation must continue, leading to the development of neutron bombs and testing them.

The development work must continue. It is an ongoing process. What was the objective of these nuclear tests? It was to have a credible, minimum nuclear deterrent. For that purpose, what you really require (is weapons) from several kilotons to a couple of hundred kilotons range. These weapons must be compact, lightweight and compatible with the delivery vehicles. This has been the basis of configuring the five tests, and I think we have sufficient information on the basis of these five tests to build a c redible, minimum nuclear deterrent.

Now, the neutron bomb is strictly a tactical weapon. There is no problem about the capability of building a neutron bomb.

The capability of building a neutron bomb in our country?

That capability exists. At this moment we are talking about this credible deterrent that can be established based on the five tests done. If you are talking about a credible deterrent, then I think that whatever has been done is sufficient.

Are you convinced that we need not explode more nuclear devices, thermo-nuclear bombs with bigger yields?

I will not put it the way you are putting it. The 45-kiloton thermo-nuclear test that we did was in a configuration which allows us to easily go up to 200 kiloton. So far as thermo-nuclear technology is concerned, there is no doubt that we have the full capability.

A thermo-nuclear device is popularly called the hydrogen bomb. According to a top DAE scientist, the hydrogen bomb and the neutron bomb are the same. Is there any difference between them?

A thermo-nuclear bomb or hydrogen bomb is a two-stage weapon, which consists of the primary which is based on fission or boosted fission system, and the secondary is where the radiation implosion is used to get a large yield. So any thermo-nuclear weapon will have a certain amount of energy coming in the form of fission, and a certain amount of energy coming in the form of fusion.

In a neutron bomb, the fusion energy is maximised. With minimum fission energy, you get maximum fusion energy. So you end up getting a much larger neutron output and so it can create much more damage by radiation. That is the difference.

But the neutron bomb is usually a small yield weapon and it is more useful as a tactical weapon.

Scientist S.K. Sikka of the BARC has been quoted as saying that computer simulation (of nuclear tests) is extremely expensive even in the United States and that therefore that country had no alternative but to do the real tests.

Yes, in those days, a long time ago. Is it less expensive now?

It is a question of availability of computing power. When the computing power that was available was small, it was probably easier to carry out the tests, in relative terms. The computing power that is available now is much higher. So you can get a lot o f information through simulation. To that extent, the number of tests that we need to carry out comes down.

Can we do computer simulation?

We certainly have some capability. We are continuously improving on it.

Are there moves afoot to split the BARC into a nuclear-weapons facility and a non-weapons facility...

There is no question of doing that. The strength of the BARC lies in its multi-disciplinary character. It is because of that we are able to run our programmes in nuclear power; national security; several aspects of isotope and radiation technology in the area of food, agriculture, health and industrial support; in the area of nuclear desalination and so forth, which is important. The BARC has a strong basic research component in physics, chemistry and biology. It has a strong technology application comp onent in electricity generation; in food security in terms of better agricultural mutants and prevention of food spoilage through radiation processing; and in health in diagnostics, that is, imaging of different body organs and radiation therapy for canc er patients. We have programmes in the area of water. We are building a 6,300-cubic-metres-a-day nuclear desalination demonstration project plant at Kalpakkam.

We give support to industry in terms of monitoring the performance of petrochemical equipment, leakage of oil pipelines, etc., using radiation technology. Even computer floppies can be treated by radiation. The BARC has the unique capability of doing all this. That comes about by its multi-disciplinary character. That has to be preserved.

How advanced is India in storing solid wastes?

We are one of the few countries that have this full capability, in the sense that we not only carry out the immobilisation of the radioactive waste in a vitrified matrix but we have the facility for interim storage of the overpacks that contain this vitr ified waste in a surveillance mode.

What does it mean?

You first concentrate the waste. You immobilise it in vitrified mass, special glass which cannot leach out. You encapsulate this vitrified mass in a metal container. This is put in another metal container and this is called overpack. This overpack is kep t in a specially engineered facility and its construction is such that there will be continuous circulation of air around this overpack. This is done by natural circulation. There are no pumps, just a chimney. It is based on physical principles so that y ou will always have natural circulation of air and so it cools. The temperature is kept under limits.

You keep monitoring the temperature and the radioactivity so that if there is any rupture, you will immediately come to know about it. You can isolate it and repair it. As time passes, 30 years or 40 years down the line, the activity decays. The heat gen eration comes down. You also confirm the integrity of the isolation, the container, the barriers to radiation. That is why it is called Solid Storage under Surveillance Facility.

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