India takes a nuclear leap in fast breeder reactor segment

India's indigenously-developed 500 MWe nuclear Prototype Fast Breeder Reactor (PFBR) in at a power plant in Kalpakkam in Tamil Nadu successfully attained first criticality on 6 April.

What does it mean in simple terms? It means that the nuclear reaction in the reactor has become safely self-sustaining and is on its way to being able to produce electricity.

There are two key takeaways from the feat: one, it puts India in the second stage of its three-stage nuclear power programme, conceived in the 1950s by Homi Jehangir Bhabha, the architect of the country's nuclear programme decades ago.

Second, once fully operational, India will become only the second country after Russia to operate a commercial fast breeder reactor. The Kalpakkam power project was formally approved in 2003 and it took 23 years to reach the second stage.

Fast breeder technology forms the vital bridge between the current fleet of pressurised heavy water reactors and the future deployment of thorium-based reactors, leveraging the country's abundant thorium resources for long-term clean energy generation.

It will no doubt take some months before the PFBR at Kalpakkam produces electricity and reaches full capacity for commercial use. A number of experiments need to be conducted at low power, which has to be evaluated by the Atomic Energy Regulatory Board (AERB) for its go-ahead for commercial power operation.

India's nuclear reactors are heavily dependent on importing enriched uranium. India's three-stage atomic power programme envisages being able to be independent of imports and be energy secure through the use of thorium, of which has vast stores.

This is where the PFBR technology comes into play the role of a bridge between the current fleet of pressurised heavy water reactors, which use enriched uranium, and the future deployment of thorium-based reactors, leveraging India's abundant thorium resources for long-term clean energy generation targets.

With the PFBR at Kalpakkam moving closer to full operation, India's long-term plan to utilise its thorium reserves is gaining momentum.

"This is a historic moment," Anil Kakodkar, member, Atomic Energy Commission and former head of the Department of Atomic Energy, told The Hindu, "What this means is that we are now on our way to extract 80-100 times more energy from a given quantity of uranium."

India has a fleet of 18-20 Pressurised Heavy Water Reactors (PHWRs) that use natural uranium as fuel and produce plutonium-239 (Pu-239) as a by-product in spent fuel, which has civilian as well as defence applications.

India's full fleet of 23 nuclear reactors has a combined capacity of 7.48 GWe.

There is, however, risk in use of sodium in PFBR technology as it is extremely chemically reactive. The risk was brought to the fore in the 1995 Monju accident in Japan where a sodium leak caused a fire and led to a 15-year shutdown of the facility.

The government of India's Atomic Energy Department has, however, held out the assurance that the reactor at Kalpakkam incorporates advanced safety systems, high-temperature liquid sodium coolant technology and a closed fuel cycle approach that enables recycling of nuclear materials, thereby improving sustainability and reducing waste.