India's Prototype Fast Breeder Reactor Achieves Criticality at Kalpakkam

India's three-stage nuclear power program, formulated by Homi J. Bhabha, aims to utilize the country's abundant thorium reserves to meet its long-term energy needs. The first stage involves pressurized heavy water reactors (PHWRs) using natural uranium. The second stage, crucial for energy self-reliance, uses fast breeder reactors (FBRs) that burn plutonium-uranium fuel while producing more fissile fuel than they consume, effectively 'breeding' fuel. The third stage aims to develop thorium-based reactors. The Prototype Fast Breeder Reactor (PFBR), developed by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) at Kalpakkam, is a 500 MWe sodium-cooled reactor designed to convert thorium-232 into fissile uranium-233, thereby enabling the transition to the third stage. Achieving criticality signifies that the reactor has initiated a self-sustaining nuclear chain reaction, marking its operational readiness after extensive design, construction, and safety checks. This achievement is vital for India's energy future, positioning it as one of only a few countries globally with operational fast breeder reactor technology. It significantly enhances India's nuclear energy independence, reduces reliance on imported uranium, and advances its capabilities in closed fuel cycle technologies. For competitive exams, this highlights India's progress in advanced nuclear technology, strategic energy policy, and scientific self-reliance.