Windscale Piles for processing in January 1952, and Tom Tuohy retrieved the first sample of British plutonium on 28 March 1952. Enough Windscale plutonium for an atomic bomb was delivered to the weapons division at Aldermaston in August, and Britain's first nuclear device was successfully detonated in the Operation Hurricane test in the Monte Bello Islands in Western Australia on 3 October 1952. Wigner energy, if allowed to accumulate, could escape spontaneously in a powerful rush of heat. On 7 May 1952, Pile No. 2 experienced a mysterious rise in core temperature despite the fact that the pile had been shut down.
Built-in self-test a periodic test will assure that the device has not become unsafe since the power-on self test. Safety-critical devices normally define a "safety interval", a period of time too short for injury to occur. The self test of the most critical functions normally is completed at least once per safety interval. The periodic test is normally a subset of the power-on self test. One of the first computer-controlled BIST systems was in the U.S.'s Minuteman Missile. Using an internal computer to control the testing reduced the weight of cables and connectors for testing. The Minuteman was one of the first