Criticality accident

Louis Slotin, a Canadian physicist working on the Manhattan Project at the Los Alamos Laboratory in New Mexico, became the second person in history to die in a nuclear criticality event, eight months after Harry K. Daghlian, Jr. became the first. Slotin was performing an experiment which attempted to begin the first stages of a nuclear reaction by enclosing a plutonium-gallium alloy bomb-core in a beryllium sphere. Slotin, who was not following proper safety protocol at the time, dropped the sphere and caused a “prompt critical” reaction that exposed him to a lethal dose of ionizing radiation. He died nine days later after suffering what doctors described as an “agonizing sequence of radiation-induced traumas”. The bomb-core that had been used during the accident was actually the same core that had killed Harry K. Daghlian, Jr. eight months prior, which was consequently nicknamed “The Demon Core” by the rest of the Manhattan Project staff.

Submission by Logan Agle. Thank you.

Oops

Harry K. Daghlian, Jr., a scientist working on the Manhattan Project at the Los Alamos Laboratory in New Mexico, became the first person in history to die in a nuclear criticality event. While preparing a bomb for the Operation Crossroads series of nuclear tests, Daghlian accidentally dropped a tungsten-carbide brick onto a plutonium-gallium alloy bomb-core, causing it to go supercritical. Daghlian received an estimated 510 REM of neutron radiation and quickly developed severe radiation poisoning. He died in a coma 25 days after the initial incident.

Submission by Logan Agle. Thank you.