A pit gate includes a gate body which is inserted between a pool portion storing water and a canal portion connected to the pool portion and is configured to change a flow state of the water, and a seal portion (6) which is accommodated in a groove-shaped accommodation recess formed in the gate body and seals between the pool portion and the gate body. The seal portion (6) includes a low-rigidity portion (10) which is relatively easily deformed by a load according to a water pressure from the pool portion side, and a high-rigidity portion (11) which is provided on the pool portion side of the low-rigidity portion and is not easily deformed relatively by the load.

A pit gate includes a gate body which is inserted between a pool portion storing water and a canal portion connected to the pool portion and is configured to change a flow state of the water, and a seal portion (6) which is accommodated in a groove-shaped accommodation recess formed in the gate body and seals between the pool portion and the gate body. The seal portion (6) includes a low-rigidity portion (10) which is relatively easily deformed by a load according to a water pressure from the pool portion side, and a high-rigidity portion (11) which is provided on the pool portion side of the low-rigidity portion and is not easily deformed relatively by the load.

There is disclosed a containment system for a nuclear plant, the containment system comprising a pressure vessel defining a containment space for containing nuclear plant structures, a working floor extending from within the containment space to outside the pressure vessel, an access opening in the pressure vessel for providing access from the working floor outside the pressure vessel to the working floor in the containment space, and an access door provided within the pressure vessel. The access door is configured to slidably move downwardly with respect to the pressure vessel from a closed position in which it closes the access opening to seal the pressure vessel, and an open position in which it reveals the access opening and is received in a door space in the working floor. The access door comprises a first integral floor plug which is configured to plug the door space in the working floor when the access door is in the open position, to provide a substantially continuous working floor surface from outside the pressure vessel to within the containment space.

A feedthrough for shielding against a radioactive radiation, the feedthrough including: electrical feedthrough conductors; a tubular metal housing including ends and seals, the ends including a respective seals so that an interior is formed in the tubular housing between the seals, the seals including an insulating body through which an electrical feedthrough conductor is fed so that an electrical feedthrough conductor is fixed in the seals while being electrically insulated from the tubular housing; a connecting conductor extending in the interior, the connecting conductor connecting an electrical feedthrough conductor at one of the seals to an electrical feedthrough conductor at another of the seals; and shielding bodies, which are respectively interrupted by at least one opening therein, the shielding bodies being arranged successively in an axial direction of the tubular housing, the connecting conductor being fed through the opening.

A feedthrough for shielding against a radioactive radiation, the feedthrough including: electrical feedthrough conductors; a tubular metal housing including ends and seals, the ends including a respective seals so that an interior is formed in the tubular housing between the seals, the seals including an insulating body through which an electrical feedthrough conductor is fed so that an electrical feedthrough conductor is fixed in the seals while being electrically insulated from the tubular housing; a connecting conductor extending in the interior, the connecting conductor connecting an electrical feedthrough conductor at one of the seals to an electrical feedthrough conductor at another of the seals; and shielding bodies, which are respectively interrupted by at least one opening therein, the shielding bodies being arranged successively in an axial direction of the tubular housing, the connecting conductor being fed through the opening.

The fuel cartridge may include a plurality of fuel channels, a first header disposed on a first side of a fuel matrix, a second header disposed on a second side of the fuel matrix opposite to the first side, and a plurality of cooling tubes through which a working fluid flows. Each of the plurality of cooling tubes may pass through each corresponding cooling channel of the plurality of cooling channels, where each of the plurality of cooling tubes has a first end connected to the first header and a second end connected to the second header. The fuel cartridge may include an interior space for sealingly containing the fuel matrix may include a pressure boundary independent from an interior of the plurality of cooling tubes, such that the interior space is not in fluid communication with the plurality of cooling tubes.

The fuel cartridge may include a plurality of fuel channels, a first header disposed on a first side of a fuel matrix, a second header disposed on a second side of the fuel matrix opposite to the first side, and a plurality of cooling tubes through which a working fluid flows. Each of the plurality of cooling tubes may pass through each corresponding cooling channel of the plurality of cooling channels, where each of the plurality of cooling tubes has a first end connected to the first header and a second end connected to the second header. The fuel cartridge may include an interior space for sealingly containing the fuel matrix may include a pressure boundary independent from an interior of the plurality of cooling tubes, such that the interior space is not in fluid communication with the plurality of cooling tubes.

Reactor buildings and vessel systems are disclosed. A nuclear power system includes: a building structure that comprises at least two exterior side walls and two end walls, at least one of the exterior walls angled non-orthogonally relative to a floor of the building structure, the at least two exterior walls and two end walls defining an interior volume of the building structure; one or more nuclear reactor systems mounted at least partially in the interior volume of the building structure; and one or more heat exchanger systems mounted at least partially to at least one of the exterior walls. A nuclear reactor vessel system includes: a nuclear fission reactor; an inner vessel that defines an inner volume sized to at least partially enclose the nuclear fission reactor; and an outer vessel sized to wholly or substantially enclose the inner vessel, the inner vessel being removable from the outer vessel.

Reactor buildings and vessel systems are disclosed. A nuclear power system includes: a building structure that comprises at least two exterior side walls and two end walls, at least one of the exterior walls angled non-orthogonally relative to a floor of the building structure, the at least two exterior walls and two end walls defining an interior volume of the building structure; one or more nuclear reactor systems mounted at least partially in the interior volume of the building structure; and one or more heat exchanger systems mounted at least partially to at least one of the exterior walls. A nuclear reactor vessel system includes: a nuclear fission reactor; an inner vessel that defines an inner volume sized to at least partially enclose the nuclear fission reactor; and an outer vessel sized to wholly or substantially enclose the inner vessel, the inner vessel being removable from the outer vessel.

A pipe cap assembly for a normally-sealed system includes a pipe cap having a base portion including two opposing, substantially parallel flat surfaces. The pipe cap includes a connector portion extending from the base portion. A fluid passage extends through both the base portion and connector portion. A transition cap may be releasably coupled to the connector portion for sealing the fluid passage during normal operation. A transition fitting provides periodic access to the sealed system and includes an access port at one end, and a tubular port and fastener at the other end. The tubular port and fastener releasably couple to the connector portion of the pipe cap to provide access. A drain hose, vent hose, or the like, may be easily coupled to the access port of the transition fitting. A test instrument may be coupled either to the access port or directly to the connector portion.