Meltdown of SL-1

January 3, 1961 - The only known fatal accident involving a nuclear reactor in America happened on this day. The SL-1, an experimental reactor operated by the U.S. Army, exploded as its main control rod was improperly removed. 3 men died.

It was all part of a program to develop a small, low-level nuclear reactor that could be used to power remote bases, like at the Arctic Circle. The accident occurred as a team of engineers worked to bring the reactor back online after an 11-day break over the holidays.

Army Specialist John Byrnes was the shift observer. Navy Seabee Richard Legg was positioned directly above the reactor. A trainee named Richard McKinley stood nearby.

It is believed that Byrnes pulled the control rod out too far which caused a massive power surge and vaporized the reactor's core. A blast of hot steam shot a shield plug upward and impaled Legg to the ceiling.

Legg and Byrnes died immediately. McKinley was still alive an hour later when a response team was finally able to enter the scene, but he died soon after.

It would take several days before all the bodies could be removed from the scene. The resulting cleanup exposed 790 people to harmful levels of radiation.

The site of the accident is a remote location about 40 miles west of Idaho Falls, Idaho. It is now a restricted area.