Abstract: A reactor cavity surrounding a reactor coolant inlet or outlet pipe is designed to reduce pressurization of the cavity in the event of a LOCA pipe break therein.

Abstract: A nuclear reactor containment arrangement incorporating a permanent cavity to vessel seal in the form of a flexible quarter-circular annular steel gasket affixed to and extending between the reactor vessel seal plate and cavity wall. The seal functions to isolate the periphery of the vessel from a permanent water-tight compartment above the reactor vessel which is flooded during refueling operations to minimize the release of radiation upon exposure of the nuclear core. The seal is designed to accommodate both radial and axial expansion of the pressure vessel relative to the cavity wall occurring during reactor operation without breaking the water-tight integrity of the seal. The pressure vessel ventilation system is provided with an air exit duct at the reactor nozzle level to facilitate the circulation of air around the periphery of the vessel which would otherwise be restricted at the seal to vessel interface.

Abstract: A modular in-core flow filter for capturing potentially harmful debris during cold hydrostatic and hot functional testing of a nuclear reactor. Since testing is carried out before fuel assemblies are placed in the reactor, multiple filters, each being of the same size and configuration, are temporarily installed on the reactor lower core plate. They fill the space which later is occupied by fuel assemblies when the assemblies are installed in an operating position. Each filter includes a square metal base having a single axial opening which desirably covers four holes in the core plate. Fine mesh and coarse mesh screens are secured in the axial opening and the unit is removably attached to the core plate by brackets which extend through the metal base and engage the underside of the core plate but are actuated into position from the upper side of the core plate. When functional flow testing of the primary coolant system has been completed, the filters are removed for subsequent use in other reactors.

Abstract: Apparatus is disclosed for handling radioactive fuel assembly during transfer operations. The radioactive fuel assembly is drawn up into a shielding sleeve which substantially reduces the level of radioactivity immediately surrounding the sleeve thereby permitting direct acess by operating personnel. The lifting assembly which draws the fuel assembly up within the shielding sleeve is mounted to and forms an integral part of the handling apparatus. The shielding sleeve accompanies the fuel assembly during all of the transfer operations.

Abstract: An emergency core cooling system for a nuclear reactor which preferably is supplemental to the main emergency core cooling system incorporated in the reactor at the time of construction. Under circumstances of a rupture in the reactor primary coolant piping and consequent drop in reactor coolant pressure, emergency supplemental coolant is supplied from tanks or accumulators through check valves into the head closure plenum area. From there, the coolant is distributed downwardly through hollow support columns and through control rod guide thimbles to the top of the fuel assemblies which comprise the reactor core. The pressure and flow of the emergency supplemental coolant is sufficiently great to overcome the normal upward flow of primary coolant through the core, the result being that the supplemental coolant causes collapse of bubbles otherwise generated by the heat producing fuel rods thereby permitting the supplemental coolant to effectively and efficiently carry away heat generated in the core.

Abstract: A fuel transfer system for moving nuclear reactor fuel assemblies from a new fuel storage pit to a containment area containing the nuclear reactor, and for transferring spent fuel assemblies under water from the reactor to a spent fuel storage area. The system includes an underwater track which extends through a wall dividing the fuel building from the reactor containment and a car on the track serves as the vehicle for moving fuel assemblies between these two areas. The car is driven by a motor and linkage extending from an operating deck to a chain belt drive on the car. A housing pivotally mounted at its center on the car is hydraulically actuated to vertically receive a fuel assembly which then is rotated to a horizontal position to permit movement through the wall between the containment and fuel building areas. Return to the vertical position provides for fuel assembly removal and the reverse process is repeated when transferring an assembly in the opposite direction.