The demon core
Stories from Physics for 11-14 14-16 16-19
A 6.2 kg mass of plutonium at Los Alamos Laboratory acquired the nickname ‘the demon core’ due to its involvement in two fatal accidents. In the first, physicist Harry Daghlian dropped a 4.4 kg tungsten carbide brick onto the core whilst doing neutron reflection experiments, initiating an uncontrolled chain reaction in the plutonium which produced a burst of ionising radiation. Though he quickly removed the brick, Daghlian had received a fatal dose - he experienced blisters and burns to his hand and died 25 days after the incident. In the second accident, Louis Slotin was fixing two halves of a reflective beryllium sphere around the core when his screwdriver slipped, causing a rapidly accelerating chain reaction and releasing a burst of ionising radiation. Slotin managed to quickly pull the two halves of the core apart, saving others in the laboratory from further exposure to radiation. He described experiencing a sour taste and his colleagues reported a blue glow of air ionisation and a wave of heat. Slotin’s condition deteriorated rapidly and he died nine days after the event.