Abstract: In a pressurized water reactor (PWR), emergency core cooling (ECC) responds to depressurization due to a vessel penetration break at the top of the pressure vessel by draining water from a body of water through an injection line into the pressure vessel. A barrier operates concurrently with the ECC to suppress flow of liquid water from the pressure vessel out the vessel penetration break. The barrier may comprise one or more of: (1) an injection line extension passing through the central riser to drain water into the central riser; (2) openings in a lower portion of a central riser to shunt some upward flow from the central riser into a lower portion of the downcomer annulus; and (3) a surge line providing fluid communication between a pressurizer volume at the top of the pressure vessel and the remainder of the pressure vessel which directs water outboard toward the downcomer annulus.

Abstract: In a pressurized water reactor (PWR), emergency core cooling (ECC) responds to depressurization due to a vessel penetration break at the top of the pressure vessel by draining water from a body of water through an injection line into the pressure vessel. A barrier operates concurrently with the ECC to suppress flow of liquid water from the pressure vessel out the vessel penetration break. The barrier may comprise one or more of: (1) an injection line extension passing through the central riser to drain water into the central riser; (2) openings in a lower portion of a central riser to shunt some upward flow from the central riser into a lower portion of the downcomer annulus; and (3) a surge line providing fluid communication between a pressurizer volume at the top of the pressure vessel and the remainder of the pressure vessel which directs water outboard toward the downcomer annulus.

Abstract: In a pressurized water reactor (PWR), emergency core cooling (ECC) responds to depressurization due to a vessel penetration break at the top of the pressure vessel by draining water from a body of water through an injection line into the pressure vessel. A barrier operates concurrently with the ECC to suppress flow of liquid water from the pressure vessel out the vessel penetration break. The barrier may comprise one or more of: (1) an injection line extension passing through the central riser to drain water into the central riser; (2) openings in a lower portion of a central riser to shunt some upward flow from the central riser into a lower portion of the downcomer annulus; and (3) a surge line providing fluid communication between a pressurizer volume at the top of the pressure vessel and the remainder of the pressure vessel which directs water outboard toward the downcomer annulus.

Abstract: In a pressurized water reactor (PWR), emergency core cooling (ECC) responds to depressurization due to a vessel penetration break at the top of the pressure vessel by draining water from a body of water through an injection line into the pressure vessel. A barrier operates concurrently with the ECC to suppress flow of liquid water from the pressure vessel out the vessel penetration break. The barrier may comprise one or more of: (1) an injection line extension passing through the central riser to drain water into the central riser; (2) openings in a lower portion of a central riser to shunt some upward flow from the central riser into a lower portion of the downcomer annulus; and (3) a surge line providing fluid communication between a pressurizer volume at the top of the pressure vessel and the remainder of the pressure vessel which directs water outboard toward the downcomer annulus.

Abstract: In a pressurized water reactor (PWR), emergency core cooling (ECC) responds to depressurization due to a vessel penetration break at the top of the pressure vessel by draining water from a body of water through an injection line into the pressure vessel. A barrier operates concurrently with the ECC to suppress flow of liquid water from the pressure vessel out the vessel penetration break. The barrier may comprise one or more of: (1) an injection line extension passing through the central riser to drain water into the central riser; (2) openings in a lower portion of a central riser to shunt some upward flow from the central riser into a lower portion of the downcomer annulus; and (3) a surge line providing fluid communication between a pressurizer volume at the top of the pressure vessel and the remainder of the pressure vessel which directs water outboard toward the downcomer annulus.

Abstract: A pressurized water reactor (PWR) includes: a pressure vessel divided into an upper plenum containing primary coolant, a lower plenum containing primary coolant, and a steam generator plenum interposed between the upper plenum and the lower plenum and containing secondary coolant; a nuclear reactor core comprising fissile material disposed in the lower plenum; one or more risers arranged to convey primary coolant upward from the nuclear reactor core to the upper plenum; and a plurality of tubes passing through the steam generator plenum and arranged to convey primary coolant downward from the upper plenum to the lower plenum. A steam separator is operatively connected with the steam generator plenum to separate secondary coolant in the steam phase from secondary coolant in the water phase.

Abstract: An integral pressurized water nuclear reactor for the production of steam utilizing a helical coil steam generator, a plurality of internal circulation pumps, and an internal control rod drive mechanism structure.

Abstract: A pressurized water reactor (PWR) comprises a pressure vessel, a reactor core disposed in the pressure vessel, an integral or external pressurizer, primary coolant disposed in the pressure vessel and heated by operation of the reactor core, and a steam generator disposed in the pressure vessel and configured to convert secondary coolant in the form of feedwater into steam by heat transfer from the primary coolant heated by operation of the reactor core to secondary coolant in the steam generator. A controller is configured to perform a PWR control method including the operations of (i) adjusting one or more parameters of the PWR and (ii) adjusting a pressurizer water level setpoint based on a predicted direction and magnitude of change of a pressurizer water level of the PWR predicted to result from the adjusting (i).

Abstract: A pressurized water reactor (PWR) includes: a pressure vessel divided into an upper plenum containing primary coolant, a lower plenum containing primary coolant, and a steam generator plenum interposed between the upper plenum and the lower plenum and containing secondary coolant; a nuclear reactor core comprising fissile material disposed in the lower plenum; one or more risers arranged to convey primary coolant upward from the nuclear reactor core to the upper plenum; and a plurality of tubes passing through the steam generator plenum and arranged to convey primary coolant downward from the upper plenum to the lower plenum. A steam separator is operatively connected with the steam generator plenum to separate secondary coolant in the steam phase from secondary coolant in the water phase.

Abstract: A containment structure contains an interior volume, and a nuclear reactor is disposed in the interior volume. An ultimate heat sink pool is disposed outside of the containment structure. A condenser includes a plurality of closed-path heat pipes or closed-path thermosiphons having first ends and opposite second ends. The closed-path heat pipes or closed-path thermosiphons are embedded in the containment structure with the first ends protruding into the interior volume and the second ends protruding outside of the containment structure.

Abstract: A pressurized water reactor (PWR) comprises a pressure vessel, a reactor core disposed in the pressure vessel, an integral or external pressurizer, primary coolant disposed in the pressure vessel and heated by operation of the reactor core, and a steam generator disposed in the pressure vessel and configured to convert secondary coolant in the form of feedwater into steam by heat transfer from the primary coolant heated by operation of the reactor core to secondary coolant in the steam generator. A controller is configured to perform a PWR control method including the operations of (i) adjusting one or more parameters of the PWR and (ii) adjusting a pressurizer water level setpoint based on a predicted direction and magnitude of change of a pressurizer water level of the PWR predicted to result from the adjusting (i).

Abstract: An integral pressurized water nuclear reactor for the production of steam utilizing a helical coil steam generator, a plurality of internal circulation pumps, and an internal control rod drive mechanism structure.

Abstract: A reactor vessel for the catalytic reforming of air and steam-fuel mix into a hydrogen rich output gas is designed to relevant pressure code requirements. The steam-fuel mix and/or air provided to the vessel may be internally pre-heated prior to contacting the catalyst. Reformate is selectively directed into a recuperator to accomplish such heating. A bypass valve to divert reformate around the recuperator is also provided to allow control of the reaction conditions. Notably, this control may be performed manually or by way of an automated system. The resulting vessel enhances the safety and performance of the vessel, and it is more easily integrated into a complete fuel processor system. A method for achieving these goals is also described.

Abstract: A steam generator system incorporates multiple processes, either in series or independently and with each process having a process fluid associated therewith, to transfer heat between a common working fluid and the process fluids in order to generate steam from the working fluid. The heat transfer may be controlled by controlling the flow of the working fluid to further regulate and control the generation of steam and/or the individual processes themselves. The generator system includes a vessel and may optionally have baffles located within the vessel to separate the flow of working fluid into a recirculation system to facilitate in the overall operation of the system. The working fluid must be capable of forming steam and preferably consists essentially of water. Straight tubes, plate-type heat exchange surfaces having a common boiling fluid stream, U-tubes, helical tubes, and/or curved tubes may be used as heat exchange means for transferring heat between the working fluid and the process fluids.

Abstract: A steam generator system incorporates multiple processes, either in series or independently and with each process having a process fluid associated therewith, to transfer heat between a common working fluid and the process fluids in order to generate steam from the working fluid. The heat transfer may be controlled by controlling the flow of the working fluid to further regulate and control the generation of steam and/or the individual processes themselves. The generator system includes a vessel and may optionally have baffles located within the vessel to separate the flow of working fluid into a recirculation system to facilitate in the overall operation of the system. The working fluid must be capable of forming steam and preferably consists essentially of water. Straight tubes, plate-type heat exchange surfaces having a common boiling fluid stream, U-tubes, helical tubes, and/or curved tubes may be used as heat exchange means for transferring heat between the working fluid and the process fluids.

Abstract: A nuclear reactor using gas as a primary coolant and a liquid as a moderator and/or reflector. Gas coolant flows through inlet passages around the outlet plenum to a distributor plate. The gas is directed between fuel element housing thimbles and fuel elements therein, through the fuel elements, and into the reactor outlet plenum. Fins on the thimble housings conduct heat to the gas from a liquid moderator circulating in the core. The use of a liquid moderator enhances safety, allows the fissile material and reactor mass to be reduced and eliminates problems associated with cooling of a solid moderator.

Abstract: A neutron flux control component for a nuclear reactor. Thin, overlapping segments of highly neutron absorbing material are positioned in the core of a reactor. The self-shielding overlapping segments are moved relative to each other to vary the amount of exposed surface area of poison to control core reactivity and to provide power shaping within the reactor core. The poison segments are mounted to carriers in the form of close-fitting concentric cylinders or rods of V-shaped cross section.

Abstract: A gas cooled nuclear fuel element. A plurality of progressively sized rigid porous cylinders nested together in coaxial alignment are provided with varying quantities of nuclear fuel to enhance the power density while remaining within temperature limitations of the fuel and base material.