The U.S.’ first fatal atomic power plant accident occurred on January 3, 1961 when a small, 3MW experimental reactor called SL-1 (Stationary Low-Power Plant No. 1) was destroyed after a control rod was removed manually. The small reactor was intended to provide electrical power and heat for small, remote military facilities, such as radar sites near the Arctic Circle.
The SL-1 was designed with a main central control rod which was able to produce a very large excess reactivity if it was completely removed. The excess reactivity is a measure of how much more capacity there is to accelerate the nuclear reaction than is required to start a controlled nuclear reaction for power generation. The potential for excess reactivity is always required because the fuel becomes less reactive over time. A greater excess reactivity causes a faster increase of the rate of the nuclear reaction. In normal operation, the control rods are withdrawn only enough to cause sufficient reactivity for a sustained nuclear reaction and power generation.
The SL-1 accident was the first fatal nuclear accident in the United States. The men killed in the incident were two Army Specialists, John Byrnes, age 25 and Richard McKinley, age 22, and Richard Legg, a 25 year old Navy Electricians Mate. Richard McKinley was interred in Arlington National Cemetery. John Byrnes and Richard Legg were buried in their hometowns in New York and Michigan.
For a YouTube video story of the SL-1 reactor, please click on: http://www.youtube.com/watch?v=gIBQMkd96CA&feature=related.