Windscale Piles were a pair of graphite-moderated nuclear reactors on the northwest coast of England in Cumberland ( now Sellafield , Cumbria ) . The two reactors , referred to at the time as " piles " , were built as part of the British post-war atomic bomb project . Their purpose was to produce weapons-grade plutonium for use in nuclear weapons . Windscale Pile No. 1 was operational in October 1950 followed by Pile No. 2 in June 1951 . They were intended to last five years , and served for seven until shut down after the Windscale fire on 10 October 1957 . Nuclear decommissioning operations commenced in the 1980s and are estimated to last beyond 2040
Windscale fire
Windscale fire
Windscale Piles