Chalk River Accident
A partial meltdown at Canada's NRX reactor caused by a series of valve errors and human mistakes, resulting in significant radioactive contamination but no deaths.
The Accident
A combination of valve errors and a mistaken attempt to correct them led to a power surge in the NRX research reactor. Cooling water was lost and four uranium fuel rods melted. The accident released millions of liters of radioactive water into the basement of the reactor building.
The Cleanup
The cleanup involved approximately 1,200 workers, each limited in exposure time. Among the cleanup crew was a young US Navy officer named Jimmy Carter, who would later become the 39th President of the United States. Carter had been trained as a nuclear engineer by Admiral Hyman Rickover.
Legacy
The Chalk River accident was one of the first significant nuclear accidents in history. It provided early lessons about the importance of multiple safety barriers, human factors in nuclear operations, and the challenges of decontamination. The NRX reactor was repaired and continued operating until 1992.
📅 Timeline
Operator error in valve room initiates accident
Power surge and partial meltdown occur
Reactor building flooded with radioactive water
Cleanup operation involving 1,200 workers