Abstract: A compact pressurised water nuclear reactor comprises a primary circuit fully integrated into the reactor vessel (10). Thus, a single steam generator (12) forms the cover of the vessel (10) and the pressuriser (30) and the primary pumps (28) are housed in the vessel (10). The same is true for the control mechanisms of the control rods (40). Finally, a venturi system (44) is also provided in the vessel (10) to create water circulation if there is a failure of the primary pumps (28).

Abstract: A compact pressurised water nuclear reactor comprises a primary circuit fully integrated into the reactor vessel (10). Thus, a single steam generator (12) forms the cover of the vessel (10) and the pressuriser (30) and the primary pumps (28) are housed in the vessel (10). The same is true for the control mechanisms of the control rods (40). Finally, a venturi system (44) is also provided in the vessel (10) to create water circulation if there is a failure of the primary pumps (28).

Abstract: A method for controlling heat exchange in a nuclear reactor. The reactor contains at least one thermal valve, at least one heat exchanger having a coolant flowing therein, with the heat exchanger being immersed in a pool containing a fluid. The heat exchanger is confined by a container having an upper part with an opening therein and a lower part having means for introducing the fluid through such lower part as well as means for partially or totally opening or closing said opening in the upper part and means for partially or totally opening or closing opening in the lower part. The method comprises the steps of closing the opening in the upper part of the container to thereby vaporize said fluid, in order to cause a cessation of heat exchange between the coolant and the fluid; and opening the opening in the upper part of the container to thereby cause the fluid to be heated and to rise by convection, thereby permitting heat exchange to occur between the coolant and the fluid.