Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. A motor may spin a linear screw to move the induction coils on a vertical travel nut. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the induction coils with a linear screw to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through a motor and rotor powering a linear screw internal to an isolation barrier. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. The magnetic fields hold closed a releasable latch to disconnect the control elements from the linear drives. A control rod assembly may join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the magnetic fields and releasable latch together on opposite sides of an isolation barrier to drive the control element to desired insertion points, including full insertion by gravity following de-energization.

Abstract: Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.

Abstract: A flow restrictor nozzle for a pressurized vessel of a nuclear reactor may comprise a nozzle body including an inlet face and an outlet face. The nozzle body may define a plurality of internal flow paths extending from the inlet face to the outlet face. Each of the plurality of internal flow paths may include a convergent section, a throat section, and a divergent section.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. A motor may spin a linear screw to move the induction coils on a vertical travel nut. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the induction coils with a linear screw to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. A motor may spin a linear screw to move the induction coils on a vertical travel nut. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the induction coils with a linear screw to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Abstract: Chimneys include several combinable parts useable in nuclear reactors. The parts are modular and removably joinable without destruction for use in directing flow in an operating nuclear reactor and directly fit in storage area during non-operation. Chimney parts are joinable through flanges and connecting structures. Chimney parts may include partitions that divide or direct energetic coolant flow from a nuclear core as well as steam separating and drying structures. The parts each individually fit within storage areas of the nuclear plant, including equipment or buffer pools in the refueling floor of the plant. Methods move the chimney parts between the reactor and storage areas, and multiple parts may be stacked or nested in such moves. Methods are useable underwater and with storage pools to prevent exposure of chimney parts during an outage. During operation, chimneys are useable in place of existing single-piece chimneys.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through a motor and rotor powering a linear screw internal to an isolation barrier. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. The magnetic fields hold closed a releasable latch to disconnect the control elements from the linear drives. A control rod assembly may join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the magnetic fields and releasable latch together on opposite sides of an isolation barrier to drive the control element to desired insertion points, including full insertion by gravity following de-energization.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through a motor and rotor powering a linear screw internal to an isolation barrier. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. The magnetic fields hold closed a releasable latch to disconnect the control elements from the linear drives. A control rod assembly may join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the magnetic fields and releasable latch together on opposite sides of an isolation barrier to drive the control element to desired insertion points, including full insertion by gravity following de-energization.

Abstract: Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.

Abstract: Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.

Abstract: A flow restrictor nozzle for a pressurized vessel of a nuclear reactor may comprise a nozzle body including an inlet face and an outlet face. The nozzle body may define a plurality of internal flow paths extending from the inlet face to the outlet face. Each of the plurality of internal flow paths may include a convergent section, a throat section, and a divergent section.

Abstract: Chimneys include several combinable parts useable in nuclear reactors. The parts are modular and removably joinable without destruction for use in directing flow in an operating nuclear reactor and directly fit in storage area during non-operation. Chimney parts are joinable through flanges and connecting structures. Chimney parts may include partitions that divide or direct energetic coolant flow from a nuclear core as well as steam separating and drying structures. The parts each individually fit within storage areas of the nuclear plant, including equipment or buffer pools in the refueling floor of the plant. Methods move the chimney parts between the reactor and storage areas, and multiple parts may be stacked or nested in such moves. Methods are useable underwater and with storage pools to prevent exposure of chimney parts during an outage. During operation, chimneys are useable in place of existing single-piece chimneys.

Abstract: A reactor pressure vessel assembly may include a housing surrounding a reactor core, steam separators, and a chimney. Inner surfaces of the chimney and reactor core define a conduit for transporting a two phase flow stream from the reactor core through the chimney to the steam separators. The housing defines an opening. An inner surface of the housing and outer surfaces of the chimney and reactor core define an annulus in fluid communication with the opening and conduit. A feedwater sparger in the housing is connected to the at least one opening and configured to deliver a sub-cooled feedwater into the annulus. A flow barrier structure between the chimney and the steam separators may force mixing between the sub-cooled feedwater and a downcomer fluid from the steam separators. An outer steam separator may be vertically over a portion of the flow barrier structure in a plan view.

Abstract: Chimneys include several combinable parts usable in nuclear reactors. The parts are modular and removably joinable without destruction for use in directing flow in an operating nuclear reactor and directly fit in storage area during non-operation. Chimney parts are joinable through flanges and connecting structures. Chimney parts may include partitions that divide or direct energetic coolant flow from a nuclear core as well as steam separating and drying structures. The parts each individually fit within storage areas of the nuclear plant, including equipment or buffer pools in the refueling floor of the plant. Methods move the chimney parts between the reactor and storage areas, and multiple parts may be stacked or nested in such moves. Methods are usable underwater and with storage pools to prevent exposure of chimney parts during an outage. During operation, chimneys are usable in place of existing single-piece chimneys.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. A motor may spin a linear screw to move the induction coils on a vertical travel nut. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the induction coils with a linear screw to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Abstract: Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through a motor and rotor powering a linear screw internal to an isolation barrier. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. The magnetic fields hold closed a releasable latch to disconnect the control elements from the linear drives. A control rod assembly may join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the magnetic fields and releasable latch together on opposite sides of an isolation barrier to drive the control element to desired insertion points, including full insertion by gravity following de-energization.

Abstract: Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.

Abstract: Chimneys include several combinable parts usable in nuclear reactors. The parts are modular and removably joinable without destruction for use in directing flow in an operating nuclear reactor and directly fit in storage area during non-operation. Chimney parts are joinable through flanges and connecting structures. Chimney parts may include partitions that divide or direct energetic coolant flow from a nuclear core as well as steam separating and drying structures. The parts each individually fit within storage areas of the nuclear plant, including equipment or buffer pools in the refueling floor of the plant. Methods move the chimney parts between the reactor and storage areas, and multiple parts may be stacked or nested in such moves. Methods are usable underwater and with storage pools to prevent exposure of chimney parts during an outage. During operation, chimneys are usable in place of existing single-piece chimneys.

Abstract: A reactor pressure vessel assembly may include a housing surrounding a reactor core, steam separators, and a chimney. Inner surfaces of the chimney and reactor core define a conduit for transporting a two phase flow stream from the reactor core through the chimney to the steam separators. The housing defines an opening. An inner surface of the housing and outer surfaces of the chimney and reactor core define an annulus in fluid communication with the opening and conduit. A feedwater sparger in the housing is connected to the at least one opening and configured to deliver a sub-cooled feedwater into the annulus. A flow barrier structure between the chimney and the steam separators may force mixing between the sub-cooled feedwater and a downcomer fluid from the steam separators. An outer steam separator may be vertically over a portion of the flow barrier structure in a plan view.