Nuclear Heart's Hidden Darkness Revealed
In the heart of the Manhattan Project, two tragic criticality accidents claimed the lives of physicists Harry Daghlian and Louis Slotin. These incidents, involving a plutonium core infamously known as the "Demon Core," occurred during criticality experiments.
The first fatality occurred with Harry Daghlian on August 21, 1945. While working at Los Alamos, he was conducting an experiment with a 6.2 kg sphere of plutonium (Pu-239) and tungsten carbide bricks. In a moment of carelessness, Daghlian inadvertently dropped a tungsten carbide brick onto the core, causing it to reach supercriticality. The ensuing burst of heat and a faint blue glow resulted in a lethal dose of gamma radiation and beta burns for Daghlian. He passed away approximately 25 days later.
Louis Slotin's accident followed on May 21, 1946. During an intricate experiment, Slotin manipulated two beryllium half-spheres (neutron reflectors) around the same plutonium core that had previously irradiated Daghlian. Slotin held one half-sphere with his left hand and maintained a gap between the halves using a screwdriver. Disregarding the approved safety protocol that required shims to prevent the halves from fully closing, Slotin's screwdriver slipped, causing the halves to come too close. An instantaneous critical reaction occurred, emitting a deadly burst of radiation. Slotin was exposed to a massive dose and died nine days after the incident.
Both accidents arose from experimental procedures that lacked adequate safety barriers and remote handling tools. These experiments on the plutonium core were conducted before such safety protocols were fully developed. The phrase "tickling the dragon's tail" was used by physicists to describe this risky practice, symbolising the danger of causing an unintended nuclear chain reaction by manipulating fissile cores too closely and carelessly.
Private Robert J. Hemmerly, the on-duty guard that night, also received radiation exposure during Slotin's accident. It is a grim reminder of the risks that the scientists and support personnel faced during the Manhattan Project.
[1] For more information, see the article "Death of a Demon: The Tragic Tale of the Demon Core" by Richard Rhodes.
Medical-conditions like lethal doses of gamma radiation and beta burns were suffered by physicists due to careless handling of plutonium cores during science experiments. Technology in the form of remote handling tools and more robust safety protocols could have prevented the fatal accidents that occurred in the Manhattan Project.
