India enters second stage of its indigenous nuclear program as PFBR attains first criticality.

India's Prototype Fast Breeder Reactor (PFBR) at the Kalpakkam Nuclear Complex reached first criticality on April 6, 2026, and is reported to mark entry into the second stage of the country's three-stage nuclear program.

The Prototype Fast Breeder Reactor (PFBR) at the Kalpakkam Nuclear Complex achieved first criticality on April 6, 2026. The reactor was designed and built domestically by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) and is part of India’s long-standing three-stage nuclear program. The Department of Atomic Energy (DAE) and historical planning by Dr. Homi Jehangir Bhabha frame this programme as a path toward using thorium at scale. The development is presented as a step toward greater energy security and technological self-reliance. Key details: - The PFBR reached its first sustained nuclear chain reaction on April 6, 2026, the article reports. - The reactor was built by BHAVINI at the Kalpakkam Nuclear Complex and has a reported capacity of 500 MWe. - This event is described as India entering Stage 2 (fast breeder reactors) of its three-stage nuclear plan. - The three-stage plan describes Stage 1 using PHWRs to produce plutonium, Stage 2 using FBRs to breed fuel, and Stage 3 aiming for thorium-based reactors. - The DAE framed the achievement as supporting India’s pathway toward energy security, technological self-reliance, and its net zero commitment for 2070. Summary: The PFBR first criticality advances India’s move from design toward operational fast-breeder technology and is presented as a key step in the three-stage programme. Undetermined at this time.