In the 1960s, America was running "Operation Plowshare": the idea that perhaps nuclear bombs could be used for peace, not war. At least some British scientists had similar ambitions, and it involved setting off a nuclear bomb under Wheeldale, in the North York Moors National Park. Based on catalogue reference ES 26 in the National Archives, mainly ES 26/2 and 26/4. "Atomic Weapons Research Establishment and Atomic Weapons Establishment: Peaceful Uses of Nuclear Explosions: Files and Reports".