Question: Cumbrians Opposed to a Radioactive Environment has campaigned against all aspects of the operation of Sellafield, formally known as which worst nuclear accident in Great Britain's history, ranked in severity at level 5 out of a possible 7 on the International Nuclear Event Scale? 
Sentence (from "Windscale fire"): The two graphite-moderated reactors, referred to at the time as "piles", had been built as part of the British atomic bomb project.
Relevant evidence: No