Superphoenix (Superphénix) is a nuclear power station on the Rhône River at Creys-Malville in France, close to the border with Switzerland. A fast breeder reactor, it halted electricity production in 1996 and was closed as a commercial plant in 1997.
Design work began in 1968, following the abandonment of the graphite-gas designs. The fast breeder design was chosen in the face of fears of disruption to the supply of other fuels; the "plutonium economy" seemed viable if oil prices stayed high and uranium supplies dwindled. Construction was approved in 1972 and lasted from 1974 to 1981, but power production did not begin until 1985. Costs rose rapidly during construction. The plant was run by the consortium NERSA, 51% owned by EDF.
There was considerable popular protest during construction; a march by 60,000 protestors in July 1977 was broken up by the CRS with the death of Vital Michalon and over a hundred serious injuries.
Power output was intended to be 1,200 MW, though during its productive period electrical generation did not come close to potential. There was understandable caution with the experimental main reactor design. As time passed problems developed from another source; the liquid sodium cooling system suffered from corrosion and leaks. In September 1990, the plant was closed. Two accidents earlier in the year had culminated in a third, which triggered an automatic shutdown. In December 1990 there was structural damage following heavy snowfall. Power production did not resume until the Direction de la Sureté des Installations Nucléaires was approved in 1992.
Power production was halted in 1996 due to cost issues, and the closure of the plant was announced in 1997. It was the last fast breeder reactor operating in Europe. Total expenditure was around 50 billion francs. The plant still contains several tons of plutonium and around 1,000 tons of sodium.