[en] The common design features between the pressurized heavy water reactor of Kraftwerk Union and a pressurized light water reactor are outlined. The first commercial power plant, with a 340 PHWR of KWU design is Atucha I which was handed over in 1974. The order for the 745 MWe Atucha II was accepted in October 1979. A description is given of the design of this plant and of the various safety engineering facilities. (U.K.)