Construction of Heysham 1, which was undertaken by British Nuclear Design & Construction, a consortium backed by English Electric, Babcock & Wilcox and Taylor Woodrow Construction, began in 1970, with the first reactor commencing operations in 1983 and the second reactor following in 1984. However, initial production levels were low, and full commercial operation was only declared in 1989. It is likely to remain in operation until 2024. Its generating capacity is 1150 MWe. The reactors were supplied by National Nuclear Corporation and the turbines by GEC. There were 4 × 17.5 MW auxiliary gas turbines on the site, these had been first commissioned in January 1977. Heysham 1 shares its reactor design with Hartlepool nuclear power station, which introduced the replaceable pod boiler design. The CEGB specified a compact design for the Heysham 1 and Hartlepool power station reactor islands in comparison to the design of the two preceding stations at Hinkley Point B and Hunterston B in order to reduce the capital cost, but this caused expensive construction delays because of restricted access. The Heysham 2 reactor island occupies a much larger footprint than Heysham 1 for a similar design output of power. In 2013 a defect was found by a regular inspection in one of the eight pod boilers of unit 1. The reactor resumed operation at a lower output level with the defective pod boiler disabled, until June 2014 when more detailed inspections confirmed a crack in the boiler spine. As a precaution, unit 2 and the sister Hartlepool nuclear power station were also shut down for inspection. All units have since returned to full power after successful inspections on the three other reactors revealed no other defects. Heysham 1 unit 1 will operate on 7 out of the 8 boiler pods until a detailed repair strategy has been developed.
Heysham 2
The construction, which was undertaken by a consortium known as National Nuclear Corporation, began in 1979 and the station opened in 1988. Its generating capacity is 1250 MWe, and it is estimated to keep running until at least 2030. Heysham 2 shares its reactor design with Torness nuclear power station and is a development of the reactor design used at Hinkley Point B. The reactors were supplied by NNC, the turbines and boilers by NEI. On 15 August 2019, Reactor 8 inside Heysham 2 let off a large amount of steam, with banging noises at approximately 11pm that could be heard 7 miles away in Lancaster. This caused alarm among local residents, and numerous calls to the police reporting “gunshots”. EDF later reported that a reactor had earlier experienced a "non-planned shutdown after an electrical fault", and the noise was from the re-start process.
