After Russia, India to be the second country in the world operating a commercial-level Fast Breeder Reactor; an indigenously designed Prototype Fast Breeder Reactor (PFBR) achieving first criticality is a significant mil...

• Prototype Fast Breeder Reactor (PFBR), a 500 MWe indigenously designed sodium-cooled reactor at Kalpakkam, Tamil Nadu, attained first criticality on 6 April 2026 at 08:25 PM.
• Marks India's formal entry into Stage II of the three-stage nuclear programme envisioned by Dr. Homi J. Bhabha, the bridge to thorium-based Stage III.
• Once commercial, India becomes the second country after Russia to operate a commercial-scale FBR.
• High UPSC salience: intersects energy security, S&T self-reliance, net-zero 2070, and the SHANTI Act, 2025 private-sector liberalisation.