High Quality Content by WIKIPEDIA articles! Sellafield is a nuclear reprocessing site, close to the village of Seascale on the coast of the Irish Sea in Cumbria, England. The site is served by Sellafield railway station. Sellafield is an off-shoot from the original nuclear reactor site at Windscale which is currently undergoing decommissioning and dismantling. Calder Hall, another neighbour of Windscale is also undergoing decommissioning and dismantling of its 4 nuclear power generating reactors.