India has achieved a major milestone in its nuclear energy programme as the indigenously designed and built Prototype Fast Breeder Reactor (PFBR) at Kalpakkam attained criticality, marking a crucial step forward in the country’s long-term atomic strategy.

Prime Minister Narendra Modi hailed the achievement, stating that India is taking a defining leap in its civil nuclear journey by advancing the second stage of its three-stage nuclear programme. He noted that the reactor’s ability to produce more fuel than it consumes reflects the depth of India’s scientific capability and engineering strength, and described it as a decisive move towards utilising the nation’s vast thorium reserves.

The 500 MWe PFBR, operated by Bharatiya Nabhikiya Vidyut Nigam Limited, represents a cornerstone of India’s nuclear roadmap. Once fully operational, India will become only the second country after Russia to run a commercial fast breeder reactor. Achieving criticality means the reactor has reached a self-sustaining nuclear chain reaction, a key milestone before full-scale power generation.

The vision behind this programme traces back to Homi Jehangir Bhabha, widely regarded as the architect of India’s nuclear strategy. Recognising India’s limited uranium but abundant thorium reserves, Bhabha conceptualised a unique three-stage nuclear power programme to ensure long-term energy security.

India’s Three-Stage Nuclear Programme

Stage 1: Pressurised Heavy Water Reactors (PHWRs)
Us of natural uranium as fuel to produce electricity, generating plutonium as a by-product.

Stage 2: Fast Breeder Reactors (FBRs)
Reactors like the PFBR use plutonium as fuel and “breed” more fissile material (including uranium-233), producing more fuel than they consume.

Stage 3: Thorium-Based Reactors
Thorium, abundantly available in India, is converted into uranium-233 and used as a sustainable fuel for long-term energy generation.

The PFBR’s success marks India’s transition into the critical second stage, bringing the country closer to fully exploiting its thorium reserves. Built with contributions from over 200 Indian industries, including several MSMEs, the project underscores the push for self-reliance under the Aatmanirbhar Bharat initiative.

This development significantly strengthens India’s position in advanced nuclear technology and clean energy, while reinforcing its long-term energy independence goals.