On April 6, India’s nuclear energy programme officially stepped into its second stage with the Prototype Fast Breeder Reactor at Kalpakkam achieving first criticality—the point at which a sustained and controlled fission chain reaction begins. Once it is fully operational, India will become only the second country after Russia to run a commercial fast breeder reactor. A closer look at the science and strategy behind this milestone: - EndsPublished By: Shyam BalasubramanianPublished On: Apr 24, 2026 18:51 IST