Abstract: Nuclear reactor installation with a light-water reactor includes a first heat exchanger, a primary and a secondary circulatory cooling loop connected in series through the first heat exchanger, the secondary circulatory cooling loop being a main cooling system for the installation, another secondary circulatory cooling loop operatively connected to the first heat exchanger, a second heat exchanger connected in the other secondary circulatory cooling loop for providing emergency cooling, the second heat exchanger being a steam convertor or steam-to-steam heat exchanger for producing low-pressure steam at a low-pressure side thereof having an inlet and an outlet and forming part of a third circulatory loop, a feedwater source independent of the main cooling system connected in the third circulatory loop at the inlet to the low-pressure side of the second heat exchanger, the outlet of the low-pressure side of the second heat exchanger being connected to a blow-off line leading to the open air.

Abstract: A nuclear reactor cooling system in which the cooling system for cooling a fuel element well is combined with the after-cooling system used at shutdown, and the emergency cooling system resulting in a substantial reduction in the number of cooling system elements required thereby reducing the overall cost of the cooling system. The fuel element well contains an excess of coolant which may then be used, in case of a break in the primary cooling circuit to supply emergency coolant to the reactor. In addition the pump and some of the lines of the fuel well cooling system are shared with the after cooling system resulting in a further reduction of components.