Kalpakkam fast breeder reactor attains criticality | What does it mean for India?

The establishment of self-sustaining nuclear chain reaction signals a key milestone in the indigenous nuclear power programme.

New Delhi: India has entered the second stage of its nuclear power programme with the 500 MW Prototype Fast Breeder Reactor at Kalpakkam in Tamil Nadu attaining “criticality”, which will pave the way for generation of electricity from a new class of nuclear power rectors, officials said here on Tuesday.

The criticality or establishment of self-sustaining nuclear chain reaction was reached at 8.25 PM on Monday (April 7), signalling a key milestone in the indigenous nuclear power programme, as envisaged by Homi Bhabha, seven decades ago.

After years of generating electricity from a fleet of pressurised heavy water reactors, the FBR – designed and developed by scientists and engineers at Indira Gandhi Centre for Atomic Research and Bharatiya Nabhikiya Vidyut Nigam Ltd - marks the beginning of a new era in nuclear power programme in which the reactor will “breed” (or produce) more fuel than what it consumes.

Once the technology is established, such reactors will help spread of nuclear energy faster at a time when the Centre has fixed a target of 100 GW of nuclear power by 2047.

Russia is the only other country to have large operational breeder reactors. “This advanced reactor, capable of producing more fuel than it consumes, reflects the depth of our scientific capability and the strength of our engineering enterprise. It is a decisive step towards harnessing our vast thorium reserves in the third stage of the programme,” Prime Minister Narendra Modi said in a social media post.

IGCAR and BHAVINI – a public sector undertaking of the Department of Atomic Energy – have begun pre-project activities on two more FBRs approved by the government. The Rs 8,181 crore PFBR, however, missed several deadlines in the last 16 years, resulting into a cost escalation by 2.5 times.

Originally it was to be commissioned by 2010, but the project kept on missing deadlines because of complicated technology, complex engineering and safety concerns as it uses highly reactive liquid sodium as coolant. At least two generations of scientists have worked on its design and development.

With the achievement of first criticality, India now moves closer to realising the full potential of its three-stage nuclear power programme.

Fast breeder technology forms the vital bridge between the current fleet of PHWRs and the future deployment of thorium-based reactors that seek to utilise abundant thorium resources found in Kerala for long-term clean energy generation.

The FBR uses uranium-plutonium mixed oxide fuel in which depleted uranium (known as U-238) is used. The reactor’s core is surrounded by a blanket of U-238 that consumes neutrons generated by the chain reaction and turn into fissile plutonium-239, enabling the reactor to produce more fuel than it consumes.

Eventually, the reactor is designed to use thorium-232, which through a nuclear process called transmutation will turn into uranium-233 – considered the best nuclear fuel - to generate electricity in the third stage of nuclear power programme.

The PFBR’s electricity generation capacity will now be ramped up progressively before it is connected to the greed.