Abstract: A nuclear power generation complex constructed on a stratum of rock overlain by soil deposits. All major structures in the power generation complex (i.e., reactor, turbine, radwaste and control buildings) are located on a common mat foundation that houses elastomeric bearings or seismic isolators. The foundation includes a concrete slab supported by a plurality of pedestals. Each of the pedestals is embedded in the rock. Preferably, each pedestal is a circular metal shell filled with underwater-type concrete, and the concrete slab is reinforced with steel bars. For example, a reactor building is supported by one set of seismic isolators mounted on the concrete slab, and a turbine building is supported by another set of seismic isolators mounted on the concrete slab. The isolators filter out a great deal of the seismic vibratory inputs. The common mat foundation eliminates differential movements between the buildings.

Abstract: A corium protection assembly includes a perforated base grid disposed below a pressure vessel containing a nuclear reactor core and spaced vertically above a containment vessel floor to define a sump therebetween. A plurality of layers of protective blocks are disposed on the grid for protecting the containment vessel floor from the corium.

Abstract: A reactor building for enclosing a nuclear reactor includes a containment vessel having a wetwell disposed therein. The wetwell includes inner and outer walls, a floor, and a roof defining a wetwell pool and a suppression chamber disposed thereabove. The wetwell and containment vessel define a drywell surrounding the reactor. A plurality of vents are disposed in the wetwell pool in flow communication with the drywell for channeling into the wetwell pool steam released in the drywell from the reactor during a LOCA for example, for condensing the steam. A shell is disposed inside the wetwell and extends into the wetwell pool to define a dry gap devoid of wetwell water and disposed in flow communication with the suppression chamber. In a preferred embodiment, the wetwell roof is in the form of a slab disposed on spaced apart support beams which define therebetween an auxiliary chamber.

Abstract: A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto.

Abstract: A nuclear fuel bundle fuel transfer system includes a transfer pool containing water at a level above a reactor core. A fuel transfer machine therein includes a carriage disposed in the transfer pool and under the water for transporting fuel bundles. The carriage is selectively movable through the water in the transfer pool and individual fuel bundles are carried vertically in the carriage. In a preferred embodiment, a first movable bridge is disposed over an upper pool containing the reactor core, and a second movable bridge is disposed over a fuel storage pool, with the transfer pool being disposed therebetween. A fuel bundle may be moved by the first bridge from the reactor core and loaded into the carriage which transports the fuel bundle to the second bridge which picks up the fuel bundle and carries it to the fuel storage pool.

Abstract: A reactor core removable fuel assembly includes upper and lower tie plates having pluralities of fuel rods and hollow control rods extending therebetween. The lower tie plate includes a lower manifold therein joined in flow communication with a reservoir containing a neutron absorbing control liquid, with the reservoir being removable from the reactor core together with the fuel assembly. The control liquid is selectively pumped from the reservoir through the lower manifold and into the control rods for selectively varying the level of the control liquid therein for controlling reactivity.

Abstract: A nuclear reactor system pressure vessel comprises a steel inner liner part, an intermediate insulative layer part and an outer pre-stressed concrete part encasing these parts. Use of the pre-stressed construction allows for construction of pressure vessels of larger size than heretofore, and this coupled with utilization of squatter reactor cores allows natural convective circulation in the reactor vessel of the heated water pool in the higher capacity systems currently being introduced. The reactor pressure vessel because of its suitability allows enhanced natural steam separation in the vessel and eliminates need for use of centrifugal steam separators. The outer vessel part can be a cast single piece structure or it can be an integrated concrete segment assembled structure embodying pre-stressing tendons arranged in various orientations to effect pre-stressing.

Abstract: A natural-circulation boiling-water reactor has skirts extending downward from control rod guide tubes to about 10 centimeters from the reactor vessel bottom. The skirts define annular channels about control rod drive housings that extend through the reactor vessel bottom. Recirculating water is forced in through the low-level entrances to these channels, sweeping bottom water into the channels in the process. The sweeping action prevents cooler water from accumulating at the bottom. This in turn minimizes thermal shock to bottom-dwelling components as would occur when accumulated cool water is swept away and suddenly replaced by warmer water.

Abstract: The wetwell space in a suppression pool of a nuclear reactor containment is continuously ventilated by exhausting gas therefrom, while at the same time, during normal system operation atmospheric air from a source of same is admitted to the wetwell but such admission being blocked during a LOCA. All exhaust flow from the wetwell is conveyed through a conduit that outlets at a remote elevated location in the atmosphere. All exhaust flow through the conduit is before outletting therefrom passed through gas treatment operation wherein any particulates in the gas mixture are removed. Further treatment of the gas with charcoal to adsorb noble gases can be carried out. In normal reactor operation the ventilation flow rate is at minimal level. However on occurrence of a loss-of-coolant-accident, highly heated gases from the containment drywell are passed into the suppression pool where condensables condense while non-condensable gases are cooled and vent to the wetwell.

Abstract: A recirculation system is disclosed for driving reactor coolant water in an annular downcomer defined between a reactor vessel and a core shroud spaced radially inwardly therefrom. The system supplies feedwater to the vessel and to a turbopump disposed inside the downcomer. The turbopump in accordance with one embodiment of the present invention includes a stationary axle and a pump impeller rotatably joined thereto and having an inlet end for receiving the coolant water from the downcomer. An annular plenum surrounds the impeller for channeling feedwater to a plurality of turbine blades joined to the impeller for rotating the impeller for driving the coolant water. The impeller is lubricated solely by the feedwater upon rotation of the impeller about the axle.

Abstract: A suppression chamber in a nuclear reactor containment includes a heat exchanger disposed in a gas space above water in the suppression chamber. A gravity-driven pool contains a supply of make-up water that is gravity fed to the heat exchanger through a conventional level-maintaining valve such as a float valve. A top header in the heat exchanger includes a free surface area for permitting separation of steam from water, thereby permitting venting of vapor only, while retaining the liquid coolant in the heat exchanger. A downcomer tube permits return of excess water to a lower location for further use in the heat exchanger. The heat exchanger is normally sealed, whereby internal surfaces in the heat exchanger require only a small amount of low-volatility corrosion inhibitors to prevent corrosion on internal surfaces thereof. Locating the heat exchanger in the gas space in the suppression chamber reduces the amount of corrosion on its external surfaces.

Abstract: A suppresion chamber in a nuclear reactor containment includes a heat exchanger disposed in a gas space above water in the suppression chamber. A gravity-driven pool contains a supply of make-up water that is gravity fed to the heat exchanger through a conventional level-maintaining valve such as a float valve. A top header in the heat exchanger includes a free surface area for permitting separation of steam from water, thereby permitting venting of vapor only, while retaining the liquid coolant in the heat exchanger. A downcomer tube permits return of excess water to a lower location for further use in the heat exchanger. The heat exchanger is normally sealed, whereby internal surfaces in the heat exchanger require only a small amount of low-volatility corrosion inhibitors to prevent corrosion on internal surfaces thereof. Locating the heat exchanger in the gas space in the suppression chamber reduces the amount of corrosion on its external surfaces.