The construction of the power station, which was undertaken by a consortium of AEI and John Thompson began in 1956. It had two Magnoxreactors producing 276 megawatts (MW) in total – enough electricity on a typical day to serve an urban area the size of Bristol. The reactors were supplied by The Nuclear Power Group (TNPG) and the turbines by AEI. Electricity generation started in 1962 and ran for 27 years to 1989.
Reactor 2 was shut down in October 1988, followed by Reactor 1 in March 1989. Berkeley was the first commercial nuclear power station in the United Kingdom to be decommissioned following its closure in 1989. So far the nuclear decommissioning process has involved the removal of all fuel from the site in 1992, and the demolition of structures such as the turbine hall in 1995 and cooling ponds in 2001. The next step of decommissioning will be the care and maintenance stage of the nuclear reactor structures, scheduled to commence in 2026, until radioactive decay means that they can be demolished and the site completely cleared between 2070 and 2080.
In March 2012 five of the 310-tonne boilers were moved from the station to Sweden for decontamination and recycling.