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.
Residual-current device to the appliance. The test button (8) allows the correct operation of the device to be verified by passing a small current through the orange test wire (9). This simulates a fault by creating an imbalance in the sense coil. If the RCD does not trip when this button is pressed, then the device must be replaced. Residual-current and overcurrent protection may be combined in one device for installation into the service panel; this device is known as a GFCI (ground fault circuit interrupter) breaker in the USA and Canada, and as an RCBO (residual-current circuit breaker with overload protection)