This Day in History: 1952-12-12

First civilian nuclear accident takes place this day at Chalk River, Ontario in 1952. A loss of coolant led the reactor core to heat up and warp, which meant graphite moderating rods could not be inserted. Hydrogen explosions and a partial core melt-down resulted. Future US president Jimmy Carter, then in the US Navy, was among the cleanup crew. The accident was the first of dozens of nuclear accidents since Chalk River.