Technology shift in India's nuclear sector

On September 2, India embarked on the next stage of its nuclear programme. The Union cabinet cleared the Department of Atomic Energy's (dae) proposal for the Rs 3,500-crore, 500-megawatt (mw) prototype of the fast-breeder nuclear power reactor (fbpr) at Kalpakkam in Tamil Nadu. Ironically, the upgrade involves a technology that is being discarded worldwide due to its poor safety record and complicated processes.

Though the fbr venture has raised the hackles of experts and activists alike, it continues to be a dream project of the Indian nuclear establishment. In fact, scientists at the Kalpakkam-based Indira Gandhi Centre for Atomic Research (igcar) have been pressing for the adoption of the technology for about three decades. The institute's director, S B Bhoje, claims that fbrs are no more risky than conventional nuclear reactors. Columnist Praful Bidwai, however, voices his concern. "I am astonished to see that igcar scientists, who could not even run a test fbr smoothly, are seeking to scale up operations to such an extent,' he remarks.

It may be noted that so far the dae has tested an fbr with a capacity of just 13 mw. Work at the test reactor began in 1985, about 13 years after construction began. Since then technical hitches have reduced its power generating capacity by one-fourth. The prototype will be built along the lines of this plant.

The need for an alternative appears to have stemmed from the country's fast-depleting stocks of uranium and widespread public protests against any fresh moves to extract the resource (see: "Critical masses", September 15, 2003). The fbpr marks the first definitive step towards the commercial exploitation of thorium as a nuclear fuel. While second-generation nuclear reactors will use a fuel comprising plutonium (30 per cent) and natural uranium (70 per cent), thorium will replace the latter in plants that are set up in the third phase. India's thorium deposits are about six times those of uranium and constitute the world's second largest reservoir of the radioactive material.

The catch is that an accident is far more probable in an fbr. Worse still, it would be much deadlier than one in a conventional water-cooled nuclear reactor. This is because the plutonium-natural uranium blend used to run an fbr is an extremely fissile fuel. The chain reaction in this type of a unit is caused and sustained by fast, highly energetic neutrons that are not "moderated', as they would be in a conventional reactor based on "thermal neutrons'. It generates intense heat, which is removed by the coolant