Overview
- India’s 500 MWe Prototype Fast Breeder Reactor at Kalpakkam, which reached first criticality on Monday, began a self-sustaining nuclear chain reaction for the first time.
- The reactor uses plutonium-based mixed oxide fuel and liquid sodium coolant, a design meant to breed new fuel and support India’s longer-term shift toward thorium.
- Engineers will run low-power physics tests and raise output in steps over the coming months before attempting any connection to the electric grid.
- IAEA chief Rafael Grossi and the International Energy Agency praised the achievement, calling it a key step toward fuel sustainability and a closed nuclear fuel cycle.
- Market watchers highlight growing attention to the nuclear supply chain, noting one prominent investor held four nuclear-related stocks in late 2025 ahead of the announcement.