India's nuclear programme is poised for a significant milestone with the scheduled commissioning of the country’s first Prototype Fast Breeder Reactor (PFBR) by September 2026. Located in Kalpakkam, Tamil Nadu, the 500 MW reactor marks the second stage of India’s three-stage nuclear power strategy, aimed at recycling spent fuel to reduce radioactive waste and support sustainable energy growth.

Developed by Bharatiya Nabhikiya Vidyut Nigam (BHAVINI), the PFBR uses a plutonium-based mixed oxide fuel and liquid sodium coolant, setting it apart as a first-of-its-kind in the country. It also utilises spent fuel from PHWRs, which currently dominate India’s nuclear energy infrastructure. "BHAVINI's 500 MW PFBR is in the advanced stage of integrated commissioning, with expected first criticality by 2025-26," Department of Atomic Energy officials informed the Parliamentary Standing Committee on Science and Technology.

Prime Minister Narendra Modi witnessed the core loading of the reactor in March last year, signalling the start of the final phase of commissioning. The Atomic Energy Regulatory Board (AERB) had previously cleared the reactor for fuel loading and low-power physics tests in July 2024. PFBRs play a pivotal role in India's closed fuel cycle strategy. Their spent fuel will feed into the development of thorium-based reactors, which form the third stage of the country’s nuclear roadmap. The government has also launched a nuclear energy mission with the aim of producing 100 GW of power from nuclear sources.

Currently, India has an installed nuclear power capacity of 8.18 GW. Projects under construction or in the commissioning stage total 7.30 GW, while an additional 7.00 GW has been sanctioned and is in the pre-project phase. Together, these will raise India's nuclear capacity to 22.48 GW by 2031-32. BHAVINI will contribute 3.80 GW through additional Fast Breeder Reactors, with the rest coming from Small Modular Reactors and advanced nuclear technologies developed alongside private players.