On January 3, 1961, a nuclear meltdown at Stationary Low-Power Plant Number 1 (SL-1) near Idaho Falls, Idaho, killed all three operators at the site: Jack Byrnes, Dick Legg, and Richard McKinley. They are, to this day, the only nuclear explosion fatalities on U.S. soil. The design of the facility, which provided power to the surrounding area, did not have the redundant fail-safe measures that newer reactors have. There were three control rods that had to be manually lifted, no more than four inches. Lifting only the central rod further would be enough to cause a meltdown -and that's what happened.
At 9:01 p.m., SL-1 exploded. “When the reactor went critical, it released so much heat energy in four milliseconds that it flashed the water surrounding the fuel to steam,” reads Stacy’s book. “[Water] slammed against the lid of the pressure vessel at a velocity of 160 feet per second and 10,000 pounds per square inch exactly as if it were a piston — a water hammer. The entire vessel jumped nine feet into the air, hit the ceiling, and thumped back into place…The violence of the explosion killed all three of the men.”
McKinley was struck in the head by a piece of radioactive shrapnel that tore off half his face. Byrnes was thrown into concrete blocks, breaking ribs that pierced his heart. Legg was skewered in the gut by a flying control rod that launched him thirteen feet in the air and pinned him to the ceiling. (It took a week to get him down, requiring a pole with a hook to push him into a net attached to a crane operated by a man shielded in lead.) The men’s bodies were wrapped in several hundred pounds of lead, placed in steel coffins, and buried under a foot of concrete.
Investigators later tried to recreate the conditions leading to the meltdown. The central rod had been lifted over twenty inches, but no man could cause that to happen in any way that could be construed as accidental. Was it sabotage, suicide, or carelessness caused by anger? We know what happened at SL-1, but we will never know exactly why. However, details of the lives of the men who were there give us some clues, which you can find out about at Longreads. -via Digg
https://longreads.com/2017/09/05/atomic-city/
In this case, the official conclusion is that it was an accident, and there is a long history of issues at that facility (like rods sticking) which no doubt directly contributed to the accident, though we can't be sure how much, exactly. The evidence for intentional sabotage is very, very weak, and the evidence for problems with the reactor is significant. In fact experts refused to believe it was possible for a reactor to fail, finding alternate explanations for the explosion and deaths, until it was proven conclusively by subsequent investigation, and safeguards were put in place for all other reactors in the aftermath.
I'll continue to give the dead men every benefit of the doubt.