The India's Three-Stage Nuclear Power Programme is a national nuclear program and strategic concept designed to secure the country's long-term energy independence. It was conceived by physicist Dr. Homi J. Bhabha in the 1950s (concept in 1954, formally accepted in 1958) to address India's resource profile: limited uranium reserves (about 1-2% of global reserves) and one of the world's largest thorium reserves (about 25% of the global total). The program's core problem is to convert the fertile Thorium-232 into the fissile fuel Uranium-233.
The mechanism is a sequential, closed nuclear fuel cycle managed by the Department of Atomic Energy (DAE). Stage 1 uses Pressurised Heavy Water Reactors (PHWRs) fueled by natural uranium to generate electricity and produce Plutonium-239 (Pu-239) as a by-product. Stage 2 employs Fast Breeder Reactors (FBRs), which use the recovered Plutonium-239 and Uranium-238 as fuel to generate power while simultaneously "breeding" more fissile material and converting Thorium-232 into Uranium-233. Stage 3 will utilize Advanced nuclear power systems, such as the Advanced Heavy Water Reactor (AHWR), fueled by Uranium-233 and Thorium-232 to achieve a self-sustaining thermal breeder cycle.
A significant recent development is the official entry into Stage 2, marked by the indigenously designed 500 MWe Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, built by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI), attaining its first criticality on April 6, 2026. The program is connected to India's goal of achieving net-zero emissions by 2070 and is supported by institutions like the Bhabha Atomic Research Centre (BARC), which is also developing parallel technologies like Small Modular Reactors (SMRs). The Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India (SHANTI) Act, 2025, was also enacted to support this mission.