Lucens reactor

Geschichte

The Lucens reactor was a 6 MW experimental nuclear power reactor built next to Lucens, Vaud, Switzerland. After its connection to the electrical grid on 29 January 1968, the reactor only operated for a few months before it suffered a loss-of-coolant accident on 21 January 1969, leading to a partial core meltdown and massive radioactive contamination of the cavern.DescriptionIn 1962 the construction of a Swiss-designed pilot nuclear power plant began. The heavy-water moderated, carbon dioxide gas-cooled reactor was built in an underground cavern and produced 30 MW of heat (which was used to generate 8.3 MW of electricity). It became critical 29 December 1966. It was fueled by 0.96% enriched uranium alloyed with chromium cased in magnesium alloy (magnesium with 0.6% zirconium) inserted into a graphite matrix. Carbon dioxide gas was pumped into the top of the channels at 6.28 MPa and 223 °C and exited the channels at a pressure of 5.79 MPa and at a temperature of 378 °C.Nuclear accidentIt was intended to operate until the end of 1969, but during a startup on 21 January 1969, it suffered a loss-of-coolant accident, leading to a partial core meltdown and massive radioactive contamination of the cavern, which was then sealed. The accident was rated 4–5 on the International Nuclear Event Scale introduced in 1990 by the International Atomic Energy Agency.