Here’s The Story Of How A Screwdriver Almost Caused An Atomic Bomb To Go Off

Demon Core (2)

You thought you could only use a screwdriver for turning screws? Louis Slotin thought it could be used for controlling a nuclear reaction.

Louis Slotin was a Canadian physicist and chemist that conducted the nuclear research at Los Alamos National Laboratory during World War II. Slotin was working with the Demon Core, the subcritical mass of plutonium, that was to be used in the third attack on Japan. May 21st, 1946, Slotin was demonstrating the operation they called ‘Tickling the dragon’s tail,’ where the subcritical core of a nuclear weapon is brought to the brink of criticality.

A recreation of Demon core experiment conducted by Slotin. Source: The New Yorker

In another criticality accident, the demon core had already caused the death of Harry K. Daghlian, Jr, another scientist who had worked on the nuclear experiments in World War II.

Slotin tested the core by placing it inside two half-spheres made of beryllium and lowered them until the sphere was almost closed. If the core were fully enclosed, the total reflection of neutrons would have resulted in an uncontrolled nuclear fission reaction. He was reported to be brazen in following experimental protocols. Instead of using the spacers to keep the sphere from closing, he was handling the beryllium spheres using the blade of a flathead screwdriver. Even though he had completed the experiment successfully many times, this time the screwdriver slipped. The top and bottom half of the beryllium sphere clunked, there was a blast of bright blue light and Slotin picked up the top half of the sphere with his bare hands. He was exposed to over 1000 rads of radiation, the highest dose of radiation anyone has ever taken. It took him 3 minutes to start vomiting with radiation poisoning.

Slotin, who was considered the world’s foremost expert on handling dangerous quantities of plutonium, died nine days later, on the 30th of May at the age of 35, in the same hospital as his colleague Daghlian. 


  1. Tim Reply

    What happened is about the worst that *could* happen under those conditions. This was nowhere near causing “an atom bomb to go off”. Even had the plutonium remained inside the sphere the worst that could happen is it would continue to self-heat and emit lethal radiation doses. Much more severe conditions would be required to cause an actual atomic explosion.

Leave a Reply

Your email address will not be published. Required fields are marked *