Unit 1 of India's Kaiga NPP in Karnataka state on 25 October completed its 895th day of continuous operation, setting a new world record for continuous operation of a pressurised heavy water reactor (PHWR).

Kaiga has four Indian design 220MWe PHWR units, which use fuel supplied by the Hyderbad-based Nuclear Fuel Complex (NFC). The operator is the Nuclear Power Corporation of India Ltd (NPCIL). Kaiga 1 has been operating without interruption since 13 May 2016. The previous record for continuous operation of a PHWR was 984 days recorded in October 1994 Canada’s Pickering 7.

The overall  record  for continuous operation of a nuclear unit is held by unit 2 of the UK Heysham NPP, an advanced gas-cooling reactor (AGR), which worked for 940 days until September 2016 when it stopped for scheduled maintenance.

The technical features of PHWR and AGR reactors allow partial refuelling without stopping the reactor. India’s nuclear power industry has recorded 28 cases of continuous operation lasting more than a year. Other record holders  are units 3 and 5 of  India’s Rajasthan NPP (also 220MWe PHWRs), with continuous operation of 777 and 765 days respectively.