India’s First Indigenous Fast Breeder Reactor at Kalpakkam Attains Criticality, Marking Major Nuclear Milestone

India’s first indigenous Prototype Fast Breeder Reactor (PFBR) at Kalpakkam in Tamil Nadu attained criticality on April 6, 2026, marking a major milestone in the country’s civil nuclear programme and a significant advance in the second stage of India’s three-stage nuclear energy strategy. Prime Minister Narendra Modi described the development as a defining step in India’s nuclear journey and congratulated the scientists and engineers associated with the project.

The 500 MWe reactor has been developed by Bharatiya Nabhikiya Vidyut Nigam Ltd. (BHAVINI) and built indigenously with contributions from more than 200 Indian industries, including MSMEs. The project has long been seen as a crucial element in India’s effort to deepen domestic capability in advanced reactor technology while aligning with the wider push for self-reliance in strategic sectors.

Fast breeder reactors are designed to produce more fissile material than they consume. According to the Department of Atomic Energy, the PFBR will initially use uranium-plutonium mixed oxide (MOX) fuel, while a surrounding uranium-238 blanket will undergo transmutation to generate additional fuel. In later stages, thorium-232 is expected to be used to produce uranium-233, linking the reactor directly to India’s long-term plan to tap its vast thorium reserves in the third stage of the national nuclear programme.

The reactor also carries major strategic and technological significance. The Department of Atomic Energy has said the PFBR is an advanced third-generation reactor equipped with passive safety features for safe shutdown during emergencies. Once fully commissioned, India is expected to become only the second country after Russia to operate a commercial fast breeder reactor, placing it in a highly select group in advanced nuclear energy deployment.

The latest milestone follows the commencement of core loading witnessed by the Prime Minister in March 2024. At the time, the Department of Atomic Energy had said that completion of core loading would lead to the reactor’s first approach to criticality and then to power generation in the subsequent stages. With criticality now achieved, the PFBR moves closer to full commissioning, strengthening India’s long-term position in advanced nuclear technology, energy security and low-carbon power generation.

Source: DD NEWS