https://youtu.be/uJ8cYheR5xo

https://en.wikipedia.org/wiki/SL-1
SL-1 Nuclear Meltdown

Stationary Low-Power Reactor Number One, also known as SL-1 or the Argonne Low Power Reactor (ALPR), was a United States Army experimental nuclear reactor located at the National Reactor Testing Station (NRTS), basis of what is now the Idaho National Laboratory, west of Idaho Falls, Idaho, United States. It is best known for the meltdown and steam explosion which occurred at 9:01 pm, on the night of January 3, 1961, killing all three of its young military operators, one of whom was pinned to the ceiling of the facility by a reactor vessel plug.[1][2][3][4] The direct cause was the improper withdrawal of the central control rod, responsible for absorbing neutrons in the reactor's core. The event is the only reactor accident in U.S. history to have resulted in immediate fatalities.[5] The accident released about 80 curies (3.0 TBq) of iodine-131,[6] which was not considered significant due to its location in the remote high desert of eastern Idaho. About 1,100 curies (41 TBq) of fission products were released into the atmosphere.[7]

The facility housing SL-1, located approximately 40 miles (65 km) west of Idaho Falls, was part of the Army Nuclear Power Program. The reactor was intended to provide electrical power and heat for small, remote military facilities, such as radar sites near the Arctic Circle, and those in the DEW Line.[8] The design power was 3 MW (thermal),[9] but some 4.7 MW tests were performed in the months prior to the accident. Operating power was 200 kW electrical and 400 kW thermal for space heating.[9] During the accident, the core power level reached nearly 20 GW in just four milliseconds, precipitating the steam explosion.[10][11][12][13]

https://timeline.com/arco-first-nuclear-accident-f16ec1105b9c

The SL-1 reactor site before its explosion. (Wikimedia)

Physicists check Highway 20 for contamination on the morning after the SL-1 accident. (Idaho National Laboratory)

A test explosion created by removing the control rod from a buried nuclear reactor at the Idaho National Laboratory—the same action which resulted in 1961's SL-1 actual accident. (Getty Images)