planning for the kkl began in 1964 for a 600 mw reactor. the swiss federal council opposed direct cooling by river water, replaced in the design in 1971 with a cooling tower. during further planning the output was increased to 600 and then 900 mw. in the wake of the 1979 three mile island accident new safety regulations were implemented, delaying completion for several years. the 2 billion swiss franc construction budget spiraled to over 5 billion before the plant opened in 1984 after eleven years of construction.