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: Nozzles mix coolant from different sources together in an outlet to prevent differences in coolant output. Different flow path configurations are useable in the nozzle, including a multiple-path configuration with flows from different sources jacketed or concentrically arranged around flows from other sources. Swirl vanes may be installed in the nozzle to impart mixing or filtering the fluid flow. Diffusers may be used to passively suction or accelerate flow and mixing the same like a jet pump. Nozzles can be combined with filtration systems like trap filters that capture debris based on a momentum difference between the denser debris and fluid. Filters can use magnetic, adhesive, or porous materials to capture debris without blocking a flow path. Filters can be disengaged, such as when clogged, such that coolant flows around the system. Nozzles can be installed on feedwater sparger assemblies in varying manner to distribute coolant from multiple nozzles.

Abstract: Nozzles mix coolant from different sources together in an outlet to prevent differences in coolant output. Different flow path configurations are useable in the nozzle, including a multiple-path configuration with flows from different sources jacketed or concentrically arranged around flows from other sources. Swirl vanes may be installed in the nozzle to impart mixing or filtering the fluid flow. Diffusers may be used to passively suction or accelerate flow and mixing the same like a jet pump. Nozzles can be combined with filtration systems like trap filters that capture debris based on a momentum difference between the denser debris and fluid. Filters can use magnetic, adhesive, or porous materials to capture debris without blocking a flow path. Filters can be disengaged, such as when clogged, such that coolant flows around the system. Nozzles can be installed on feedwater sparger assemblies in varying manner to distribute coolant from multiple nozzles.

Abstract: A reinforcement assembly may be provided for a bracket configured to constrain a cooling pipe of a spent fuel pool of a nuclear reactor. The reinforcement assembly includes a base structure defining back slots, angled slots, side slots, and/or front slots. Back boss structures may be configured to slidably engage with the back slots of the base structure. Pipe boss structures may be configured to slidably engage with the angled slots of the base structure. Side clamps may be configured to slidably engage with the side slots of the base structure. Each of the side clamps may define a vertical slot. Vertical clamps may be configured to slidably engage with the vertical slot of each of the side clamps. Front clamps may be configured to slidably engage with the front slots of the base structure.

Abstract: Seals are positioned between abutting nuclear reactor components. Example seals are held in position by gravity, grooves, retainers, direct joining, or other mating structures to seal the abutting components. Compression of example seals drives the seals against the joining components, preventing fluid passage therebetween. Example seals may include a cavity opening to a higher pressure fluid outside the joined components to drive expansion or sealing of the seal. Seals may have a C-shaped, E-shaped, O-ring, coiled, helical, or other cross-section to provide such a cavity. Example seals may be flexible materials compatible with radiation and heat encountered in a nuclear reactor. Seals may be continuous or sectional about the abutment of the components. An annular seal may extend continuously around a perimeter of removably joined core plates, supports, shrouds, and/or chimney heads and structures. Seals can be installed between and in the components at any time access is available to the components.

Abstract: A reinforcement assembly may be provided for a bracket configured to constrain a cooling pipe of a spent fuel pool of a nuclear reactor. The reinforcement assembly includes a base structure defining back slots, angled slots, side slots, and/or front slots. Back boss structures may be configured to slidably engage with the back slots of the base structure. Pipe boss structures may be configured to slidably engage with the angled slots of the base structure. Side clamps may be configured to slidably engage with the side slots of the base structure. Each of the side clamps may define a vertical slot. Vertical clamps may be configured to slidably engage with the vertical slot of each of the side clamps. Front clamps may be configured to slidably engage with the front slots of the base structure.

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: Nozzles mix coolant from different sources together in an outlet to prevent differences in coolant output. Different flow path configurations are useable in the nozzle, including a multiple-path configuration with flows from different sources jacketed or concentrically arranged around flows from other sources. Swirl vanes may be installed in the nozzle to impart mixing or filtering the fluid flow. Diffusers may be used to passively suction or accelerate flow and mixing the same like a jet pump. Nozzles can be combined with filtration systems like trap filters that capture debris based on a momentum difference between the denser debris and fluid. Filters can use magnetic, adhesive, or porous materials to capture debris without blocking a flow path. Filters can be disengaged, such as when clogged, such that coolant flows around the system. Nozzles can be installed on feedwater sparger assemblies in varying manner to distribute coolant from multiple nozzles.

Abstract: A method and apparatus for a boiling water reactor (BWR) jet pump inlet mixer compliant stop. The inlet mixer compliant stop may be installed in a pocket area between a riser pipe and an inlet mixer of a BWR jet pump assembly. The inlet mixer compliant stop includes a main body and a foot that are separated via the tightening of one or more jacking bolts used to connect the main body and the foot. A cold spring attached to the main body provides a lateral force that is imparted on the inlet mixer, to force the inlet mixer away from a centerline of the riser pipe. A precise lateral force may be imparted on the inlet mixer by gauging a width of a gap between opposing bosses on a front face of the main body and a distal end of the cold spring. The inlet mixer compliant stop imparts a greater lateral force on the inlet mixer as the jacking bolts are tightened, further separating the main body from the foot, as the gap between the opposing bosses is reduced.

Abstract: A method of storing a chimney assembly of a reactor pressure vessel during a nuclear reactor outage includes detaching a chimney barrel with upper chimney partitions therein from a top guide assembly of the reactor pressure vessel. A height of the upper chimney partitions is less than a height of the chimney barrel so as to leave a plenum region in a top section of the chimney barrel. The top guide assembly includes lower chimney partitions therein. The lower chimney partitions are removed from the top guide assembly and inserted into the plenum region of the chimney barrel so as to be on the upper chimney partitions. As a result, the chimney assembly can be stored in a relatively compact form during a reactor outage. The chimney assembly includes a combination of at least the chimney barrel, the upper chimney partitions, and the lower chimney partitions.

Abstract: Seals are positioned between abutting nuclear reactor components. Example seals are held in position by gravity, grooves, retainers, direct joining, or other mating structures to seal the abutting components. Compression of example seals drives the seals against the joining components, preventing fluid passage therebetween. Example seals may include a cavity opening to a higher pressure fluid outside the joined components to drive expansion or sealing of the seal. Seals may have a C-shaped, E-shaped, O-ring, coiled, helical, or other cross-section to provide such a cavity. Example seals may be flexible materials compatible with radiation and heat encountered in a nuclear reactor. Seals may be continuous or sectional about the abutment of the components. An annular seal may extend continuously around a perimeter of removably joined core plates, supports, shrouds, and/or chimney heads and structures. Seals can be installed between and in the components at any time access is available to the components.

Abstract: An apparatus for controlling movement of a first component integrated with a second component may include a first clamp configured to engage the first component, a second clamp configured to engage the second component, and a plurality of connectors configured to connect the first and second clamps. The connectors may allow movement of the first clamp relative to the second clamp in a first direction between the first and second clamps. The connectors may limit movement of the first clamp relative to the second clamp in a second direction perpendicular to the first direction.

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.

Abstract: A method of storing a chimney assembly of a reactor pressure vessel during a nuclear reactor outage may include detaching a chimney barrel with upper chimney partitions therein from a top guide assembly of the reactor pressure vessel. A height of the upper chimney partitions is less than a height of the chimney barrel so as to leave a plenum region in a top section of the chimney barrel. The top guide assembly includes lower chimney partitions therein. The lower chimney partitions are removed from the top guide assembly and inserted into the plenum region of the chimney barrel so as to be on the upper chimney partitions. As a result, the chimney assembly can be stored in a relatively compact form during a reactor outage. The chimney assembly may be a combination of at least the chimney barrel, the upper chimney partitions, and the lower chimney partitions.

Abstract: A method and apparatus for securely fastening a pipe collar or a bracket to a riser pipe of a boiling water reactor (BWR) jet pump assembly. A pipe plug assembly includes an angled pipe plug that acts as a wedge to expand a bushing assembly as the pipe plug is drawn into the overall pipe plug assembly. Expansion of the bushing assembly allows a tight tolerance to exist between an outer diameter of the pipe plug and an inner diameter of the collar/bracket and riser pipe. Expansion of the bushing assembly allows a straight hole to be match drilled into the collar/bracket and riser pipe, thereby avoiding a more complicated tapered hole to be drilled into the collar/bracket and riser pipe. An ensuing tight fit between the pipe plug assembly, the collar/bracket and the riser pipe mitigates vibration of components and minimizes leakage to acceptable levels for use in the flooded environment of the annulus region where the jet pump assembly exists in the BWR.