A plutonium sphere at Los Alamos was never meant to become a legend — so how did the Demon Core end up tied to two fatal criticality accidents? In this episode, we unpack the Demon Core, Harry Daghlian, Louis Slotin, and the physics and safety failures behind the lab tragedies, so listen now and hear the real story before the myths take over.

The Demon Core was a 6.2 kg plutonium-gallium sphere at Los Alamos that became infamous after two separate criticality accidents killed physicists Harry Daghlian and Louis Slotin. In this episode, we unpack the Demon Core, criticality accidents, neutron reflectors, and why a tiny change in geometry can turn a lab experiment deadly.

• How the Demon Core went from wartime bomb core to radiation-safety cautionary tale
• Why tungsten-carbide bricks and a beryllium reflector changed everything
• What “criticality excursion” and “prompt criticality” actually mean
• How the accidents shaped modern nuclear safety and remote handling rules

00:00 — A small lab slip with huge consequences
03:10 — What the Demon Core was
07:05 — The Harry Daghlian accident
11:20 — The Louis Slotin accident
16:00 — What changed in nuclear safety afterward

Related resources: Internal: /episodes/demon-core | External: https://en.wikipedia.org/wiki/Demon_core | https://ahf.nuclearmuseum.org/ahf/history/atomic-accidents/ | https://en.wikipedia.org/wiki/Criticality_accident

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