the first discussions about the construction of the third swiss nuclear power plant started in 1966. in 1970 the formal request was submitted to the federal authorities. initially foreseeing a river water cooling, the blueprints had to be modified in order to meet a new federal regulation that in 1971 forbade such systems for future plants. after the introduction of a cooling tower, the authorities issued the location authorization on 31 october 1972. the construction started in summer 1973, after that a series of local permits had been granted. the commissioning was authorized on 29 september 1979. the kkg was ready to start operation in february 1979, but the three mile island accident led the swiss federal council to order a security check on the swiss plants that took some months. it eventually entered its commercial phase on 1 november 1979. the unlimited operating license was issued on 29 september 1978.