Major Nuclear Power Mishaps in 35 Countries Since 1990

The United Kingdom has used nuclear power since the 1950s. Most of its reported nuclear and radiological-related incidents since 1990 involve nuclear power facilities, notably the Sellafield multi-function nuclear site on the coast of Cumbria in northwestern England. In 1957, the Windcastle Fire at Sellafield was an INES level 6 accident.

All but two of the incidents since 1990 measured below INES level 3. The first of the two level 3 events occurred at Sellafield in September 1992, when plutonium nitrate leaked from a corroded pipe into a containment cell while safety devices failed to detect further leakage out of the cell. The second level 3 incident took place in April 2005, when a fractured pipe at a reprocessing plant at Sellafield leaked uranium and plutonium dissolved in nitric acid.

Having the world’s largest nuclear power plant industry and a large number of industries that use irradiated materials, it should be no surprise that the United States reported the most nuclear and radiological-related incidents since 1990. France is the only other country with more than 100 of these events during that time.

Though there were several INES level 4 accidents in the U.S. before 1990, including INES level 5 at Three Mile Island in 1979, all but three of the events since 1990 rated below INES level 3. The three level 3 events included a March 2002 incident at the Davis-Besse Nuclear Power Station in Oak Harbor, Ohio, when an inspector discovered a severely eroded reactor component that could have caused a more serious incident.