Source: Nuclear Power Corporation of India LtdA new world record for continuous operation of a pressurized heavy water reactor — 895 days — and the second-longest for a nuclear power reactor of any type has been set by Unit 1 of India's Kaiga nuclear power plant.

The 220 MW Indian-designed and domestically fueled reactor has now operated without a break since May 2016. Kaiga 1 is one of three Indian reactors to have operated continuously for more than two years, alongside Rajasthan unit 3, with 777 days of continuous operation, and Rajasthan 5, with 765 days.

The current world record for continuous operation for a commercial nuclear power reactor of any type is held by unit 2 of the U.K.'s Heysham II plant, an advanced gas-cooled reactor that had completed an unbroken 940 days in service when it was taken offline for a scheduled maintenance outage in September 2016.

The Nuclear Power Corporation of India Ltd currently operates 22 nuclear reactors with a combined capacity of 6,780 MW. Eight reactors with a combined capacity of 6,200 MW are now under construction.