Abstract: A clamped support system for a structure comprising a plurality of support piers in a predetermined array, supporting the structure; and at least two rigid reinforcing pads sandwiched about an elastomer layer, the plurality of support piers extending through the reinforcing pads and the elastomer layer.

Abstract: An apparatus for removing and installing a reactor component, such as a circulating pump, by remote operation. The apparatus includes a handling mechanism for transporting various interchangeable containers and tools along a path between a position on top of the suppression pool and a position overlying the reactor component. The handling mechanism has a yoke assembly adapted to receive and support the trunnions of any container or tool, lifting screws for raising and lowering the yoke assembly and an arcuate rack mounted on the shield wall for rotating the yoke assembly around the circumference of the shield wall. A transition collar is latched onto the pump pressure housing. The transition collar has a valve at the top for closing off its interior. Seals arranged between the transition collar and pressure housing to ensure water-tightness.

Abstract: A nuclear reactor having a pressure vessel which is open at the top. The open top of the pressure vessel is closed by a steel dome. A containment, which is open at the top, extends upward from and is joined to the top of the pressure vessel and has an open containment head at the top thereof. The open top of the containment is closed by a steel dome, thereby forming a containment well bounded laterally by the containment, on the bottom by the vessel closure and on the top by the containment closure. The pressure vessel can be a steel-lined prestressed concrete vessel, while the containment is formed by an extension of the prestressed concrete vessel. Alternatively, the pressure vessel and the containment are parts of a unitary steel vessel. Isolation valves are installed on each penetration pipeline to isolate the system in the event of a loss-of-coolant accident.

Abstract: A fuel bundle assembly for a boiling water nuclear reactor includes an open ended tubular channel subdivided into four quadrants by at least two interior partitions, each quadrant having a sub-fuel bundle assembly having a plurality of fuel rods extending between upper and lower tie plates. An inter-bundle support plate receives a lower end of the channel and has four flow openings at an upper end thereof, such that the lower tie plate of each sub-fuel bundle supported in a respective one of the openings in the support plate. In one embodiment, the sub-fuel bundles within a channel are separated by a cruciform shaped coolant passage. In a second embodiment, the cruciform coolant passage is omitted to thus provide a homogeneous sub-fuel bundle configuration.

Abstract: A control rod drive having a magnetic coupling device which eliminates the need for packing-type seal assemblies for preventing leakage from the reactor pressure vessel adjacent the spindle. The magnetic coupling device includes a driving rotor and a driven rotor separated by a pressure barrier which forms part of the reactor pressure boundary. The driven rotor and the driving rotor are coupled magnetically so that the driven rotor rotates in response to rotation of said driving rotor, whereby the control rod displaces in response to operation of the drive motor. The driven and driving rotors are each constructed by stacking a plurality of circular magnetic rings concentric with a centerline axis. Each circular ring has multiple poles circumferentially distributed thereon. An anti-rotation device is incorporated to prevent free rotation of the spindle when the drive motor is removed during maintenance operations. The anti-rotation device includes a push rod actuator which penetrates the pressure barrier.

Abstract: A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives.

Abstract: A control rod is selectively positioned in a nuclear reactor core inside a reactor pressure vessel by a drive assembly. The assembly includes a flexible cable releasably joined to the control rod by a coupling. A drive is joined to the cable for selectively advancing and retracting in opposite directions the cable for selectively positioning the control rod in the reactor core. In exemplary embodiments, the drive and cable may be disposed above or below the reactor core. In another embodiment, a pressurized driving fluid may be used to additionally position the control rod within the reactor core.

Abstract: A fluid coupling includes first and second connectable fittings. Each of the fittings include a body, an annular seat, and a fluid channel extending through the body and seat thereof. The first fitting includes a pair of latch bosses, and the second fitting includes a pair of latch arms, with the second fitting being rotatable relative to the first fitting to a latched position wherein the latch arms engage the latch bosses for maintaining the first seat adjacent to the second seat for allowing fluid to flow between the first and second channels. The fittings are also rotatable to a disengaged position wherein the latch arms and pins are disengaged to allow the first and second seats to be separated.

Abstract: A reactor steam isolation cooling system includes a containment building surrounding a reactor pressure vessel having a reactor core for generating reactor steam. An isolation pool is disposed outside the containment building and is vented to the atmosphere. An isolation condenser includes a plurality of heat pipes collectively defining at one end thereof a condenser assembly disposed outside the containment building and inside the isolation pool, and at an opposite end thereof an evaporator assembly extending inside the containment building. Reactor steam is selectively channeled to the evaporator assembly for heating a working liquid therein and condensing the reactor steam to form reactor condensate for return to the pressure vessel. The working liquid is vaporized in the evaporator assembly and flows to the condenser assembly wherein it releases heat into the isolation pool with the working condensate therefrom returning to the evaporator assembly.

Abstract: A reactivity control system includes a reservoir containing a liquid nuclear poison, at least one stationary, hollow control blade extending vertically into a reactor core, and a poison conduit disposed in flow communication between the reservoir and the control blade for channeling the poison between the reservoir and control blade. The level of the poison in the control blade is controlled for selectively varying nuclear reactivity in the core.

Abstract: A method is disclosed for monitoring braking torque capability of a brake used for selectively braking a shaft of an exemplary control rod drive. The method includes the steps of rotating the shaft, engaging the brake, torsionally restraining the brake for allowing rotation of the brake up to a predetermined maximum angle, and monitoring the angle for monitoring braking torque capability of the brake. A preferred embodiment of a brake assembly for carrying out the method includes a stationary base, a bearing mounted to the base, a brake mounted to the bearing for rotation relative to the base, means for torsionally restraining the brake for allowing rotation of the brake up to the predetermined maximum angle, and means for monitoring the angle.

Abstract: A recirculation system is disclosed for driving reactor coolant water contained in an annular downcomer defined between a reactor vessel and a reactor core spaced radially inwardly therefrom. The system includes a plurality of circumferentially spaced pumps disposed in the downcomer, each pump including an inlet for receiving coolant water from the downcomer as pump inlet flow, and an outlet for discharging the pressurized water. The recirculation system firstly increases the pressure of the pump inlet flow at the pump inlet before being sucked into the pump for being further pressurized by the pump.

Abstract: A drive for positioning a control rod in a nuclear reactor core is disclosed. The drive includes a housing having a piston disposed therein, with a piston rod extending from the piston and through the housing for being joinable to the control rod. A driving fluid is provided into the housing for exerting a pressure force against the piston for moving the piston and the control rod. The output requirements for the driving fluid are varied in response to the position of the piston for selectively controlling intermediate positions of the piston.

Abstract: A boiling water nuclear water plant includes a reactor core isolation cooling (RCIC) system in which a turbine used to pump feedwater to the reactor also drives a generator. The generator is used to drive RCIC components, such as a room cooler and control electronics, during station blackout.

Abstract: A drive for positioning a control rod in a nuclear reactor core is disclosed. The drive includes a turbine rotor joined to a hollow spindle in a housing. The spindle has a piston disposed therein and a piston rod extending therefrom and through a bottom end of the spindle for being joined to the control rod. A pressurized fluid is provided into the spindle for exerting a pressure force against the piston for moving the piston for selectively gripping the control rod. Interruption of the pressurized fluid to the spindle causes ungripping of the control rod.

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 drive for moving a control rod in a pressure vessel containing a pressurized fluid includes a spindle disposed solely within the pressure vessel, which spindle is effective for moving the control rod upon rotation thereof. A driven rotor is fixedly joined to the spindle within the pressure vessel for rotating the spindle, and the driven rotor is selectively rotated in first and second opposite directions without the need for packing-type seal assemblies for preventing leakage of the pressurized fluid from the pressure vessel adjacent to the spindle.

Abstract: A nuclear reactor includes a spaced sidewall and a core shroud defining a flow passage for channeling a coolant. A foreign object separator includes an arcuate endwall extending from the sidewall, with the core shroud including an intermediate portion spaced from the endwall to define an annular inlet for receiving coolant from the flow passage. The core shroud also includes a distal end spaced from the endwall to define a throat. A separator member has a proximal end joined to the endwall, and a distal end spaced from the core shroud to define an outlet. The distal end of the separator is spaced from its proximal end for allowing the coolant from the throat to impinge against the separator member for turning the coolant prior to discharge from the outlet and using centrifugal force to separate any foreign objects of predetermined size from the coolant. The separated foreign objects are retained adjacent to the separator member proximal end.

Abstract: A rotary lock is disclosed for preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The lock includes a stationary housing for receiving the shaft, and an arm extending outwardly from the shaft. At least one pin is joined to the housing for circumferential restraint and is positionable in a withdrawn position away from the arm for allowing the arm to rotate with the shaft without obstruction from the pin. The pin is also positionable in a deployed position contacting the arm for preventing rotation of the arm and shaft. Means are provided for selectivity positioning the pin in the withdrawn and deployed positions.

Abstract: In an arrangement for feeding a fluid at a given temperature into a vessel containing fluid at a different temperature from an inlet pipe through an inlet nozzle to feedfluid distribution means in the vessel, a removable thermal isolator arrangement is provided. Spaced concentric sleeves form a series of fluid spaces which thermally insulate the inner surface of the nozzle from the feedfluid and leakage feedfluid is directed away from the nozzle whereby thermal cycling of the inner surface of the nozzle is minimized to eliminate cracking thereof.