Abstract: A reactor cooling system for boiling water reactors comprises a pressure vessel containing a core of a boiling water reactor, a static core injection system including a first water source installed at a position higher than the pressure vessel and a first core injection line communicating the first water source with the pressure vessel, and having a capacity not less than 100% of the capacity necessary to maintain submergence of the core in the pressure vessel, and a plurality of dynamic core injection systems each including a second water source, a second core injection line communicating the second water source with the pressure vessel, and a pump provided in the second core injection line, and each having a capacity not less than 50 % of the capacity necessary to maintain submergence of the core in the pressure vessel.

Abstract: A pressure control chamber of a reactor containment vessel for receiving the atmosphere of the reactor containment vessel containing leakage steam developing in the event of an accident includes a pressure control pool, and a wet well disposed above the pressure control pool. The wet well is divided into an inner peripheral portion and an outer peripheral portion. The inner and outer peripheral portions are communicated with each other via the pressure control pool. An outlet port for flowing the atmosphere of the reactor containment vessel containing the leakage steam is provided at the inner peripheral side of the pressure control pool. When the atmosphere of the reactor containment vessel containing the leakage steam is introduced into the pressure control pool in the event of the accident, this atmosphere is condensed by the water in the pressure control pool, and the gas of this atmosphere not condensed is accumulated in the inner peripheral portion of the wet well.

Abstract: A nuclear reactor facility including a primary containment vessel, a reactor pressure vessel installed in the primary containment vessel and accommodating a reactor core in a lower part thereof, and a vertical cylindrical wall disposed in a lower part of the primary containment vessel around and spaced from the reactor pressure vessel so as to delimit an annular space therebetween. The vertical cylindrical wall has an upper end disposed at a position higher than an upper end of the reactor core and a diaphragm extends substantially horizontally between the upper end of the vertical cylindrical wall and an inner wall of the primary containment vessel for cooperating with the vertical cylindrical wall to separate a space in the primary containment vessel around the reactor pressure vessel into a pressure suppression chamber and a drywell which includes annular space.

Abstract: A container-outer-periphery pool in which water is stored is provided between a primary containment vessel and a reactor building, and outside of a pressure suppression pool. Consequently, the natural heat transfer capabilities of reactor facilities is enhanced, and the inherent safety of the reactor facilities is improved.

Abstract: An apparatus for decontaminating a radioactively contaminated coolant flowing through the core of a nuclear reactor wherein the coolant containing radioactively contaminated impurities is withdrawn from the core, precooled and cooled, and then the impurities are removed therefrom by ion exchange, before the coolant is returned to the core.