Wylfa nuclear power station () is a Magnox nuclear power station undergoing decommissioning. Wylfa is situated west of Cemaes Bay on the island of Anglesey, off the northwestern coast of Wales. Construction of the two 490MW nuclear reactors, known as Reactor 1 and Reactor 2, began in 1963. They became operational in 1971. Wylfa was located on the coast because seawater was used as a coolant. In 2012, Reactor 2 was shut down. Reactor 1 was switched off on 30 December 2015, ending 44 years of operation at the site. Wylfa Newydd (literally New Wylfa) was a proposed new nuclear station on a site adjacent to the old plant. An application to build two advanced boiling water reactors was submitted by Horizon Nuclear Power to the Office of Nuclear Regulation on 4 April 2017. , parent company Hitachi has withdrawn from the project. In 2022, the UK parliament expressed interests about the construction of a possible set of two EPR reactors on the site. History Wylfa was the second nuclear power station to be built in Wales after Trawsfynydd in 1959. Following the closure of Trawsfynydd in 1991, Wylfa became Wales' only nuclear power station. Construction of Wylfa, which was undertaken by British Nuclear Design & Construction (BNDC), a consortium backed by English Electric, Babcock & Wilcox Ltd and Taylor Woodrow Construction, began in 1963. The reactors were supplied by The Nuclear Power Group (TNPG) and the turbines by English Electric. These were the largest and last Magnox-type reactors to be built in the UK. Wylfa was also the second British nuclear power station, following Oldbury, to have a pre-stressed concrete pressure vessel instead of steel for easier construction and enhanced safety. Wylfa's two 490MW Magnox nuclear reactors, Reactor 1 and Reactor 2 became operational in 1971. They typically supplied 23GWh of electricity daily when they were both in service. Although the original design output was 1,190MW, unexpected accelerated ("breakaway") corrosion of mild steel components of the gas circuit in hot was detected even before the first reactor began operating. The channel gas outlet temperature, the temperature at which the leaves the fuel channels in the reactor core, had to be reduced, initially dropping the power output to 840MW, which was later raised to 980MW as more experience accumulated. A considerable portion of the output, up to 255MW, was consumed by the nearby Anglesey Aluminium smelting plant. The graphite cores