India’s first Prototype Fast Breeder Reactor (PFBR), located in Kalpakkam, Tamil Nadu, is set to be commissioned by September 2026, marking a pivotal advancement in the nation’s nuclear energy ambitions.

This 500 MW reactor, developed by Bharatiya Nabhikiya Vidyut Nigam (BHAVINI), represents the second stage of India’s three-stage nuclear programme, which is designed to recycle spent nuclear fuel and significantly reduce radioactive waste inventory.

The PFBR is unique as it is the first Indian reactor to use plutonium-based mixed oxide (MOX) fuel and liquid sodium as a coolant. It will also utilise the spent fuel from Pressurised Heavy Water Reactors (PHWRs), which are currently the backbone of India’s nuclear power generation.

The core loading of the PFBR began in March 2024, an event witnessed by Prime Minister Narendra Modi, and the first criticality—when the reactor becomes self-sustaining—is expected to be achieved by 2025-26.

The Atomic Energy Regulatory Board (AERB) granted the necessary approvals for fuel loading and initial low-power experiments in July 2024, paving the way for the reactor’s final commissioning. Once operational, the PFBR will make India only the second country after Russia to have a commercial fast breeder reactor, showcasing the country’s indigenous technological capabilities and its commitment to self-reliance (Aatmanirbhar Bharat) in the nuclear sector.

The PFBR is central to India’s long-term energy security and decarbonisation goals. Its design allows for the breeding of more fissile material than it consumes, particularly by converting uranium-238 and, in future phases, thorium-232 into usable nuclear fuel.

This capability is crucial for India, which has abundant thorium reserves but limited uranium resources. The spent fuel from the PFBR will be used in the third stage of India’s nuclear programme, which envisions thorium-based reactors for sustainable and large-scale power generation.

In terms of safety, the PFBR incorporates advanced passive safety features, ensuring prompt and secure shutdown in emergencies. The reactor’s operation will also help reduce the need for large-scale geological disposal facilities by minimising nuclear waste through recycling. The capital and per-unit electricity costs are expected to be on par with other nuclear and conventional power plants, making it a competitive addition to India’s energy mix.

Looking ahead, India’s nuclear energy mission aims to achieve 100 GW of electricity from nuclear power. The current installed capacity stands at 8.18 GW, with an additional 7.30 GW under construction or commissioning, and 7.00 GW sanctioned for future projects.

By 2031-32, the installed capacity is projected to reach 22.48 GW, with further expansions planned through indigenous PHWRs, Light Water Reactors (with foreign cooperation), and advanced technologies such as Small Modular Reactors and Bharat Small Reactors. BHAVINI is expected to contribute 3.80 GW through additional fast breeder reactors, underscoring the strategic importance of the PFBR for India’s energy landscape.

The commissioning of the PFBR at Kalpakkam is a landmark achievement for India’s nuclear sector, enabling the transition to advanced fuel cycles, supporting energy security, and paving the way for the eventual utilisation of India’s vast thorium resources.