A reactor pressure vessel includes a reactor pressure vessel body, a nozzle structure connected to the reactor pressure vessel body, a conduit structure connected to the nozzle structure, and a restraint device attached around a portion of the conduit structure. The restraint device includes collar parts that have cross sections corresponding to respective segments of a periphery of the portion of the conduit structure, brackets attached to the nozzle structure, and rods connecting the brackets to the collar parts. The collar parts are connected end-to-end to each other such that a cross section of the collar parts connected to each other corresponds to the periphery of the portion of the conduit structure. The collar parts are pinned to each other. The brackets spaced apart from each other around a periphery of the nozzle structure.

An assembly is provided that includes a device for locking tubes in position relative to one another, with at least a first arm, a locking axle having a plurality of bearing surfaces, the locking axle being movable between a position locking the tubes each between one of said bearing surfaces and the first arm, and a released position, in which the tube segments are free.

An assembly is provided that includes a device for locking tubes in position relative to one another, with at least a first arm, a locking axle having a plurality of bearing surfaces, the locking axle being movable between a position locking the tubes each between one of said bearing surfaces and the first arm, and a released position, in which the tube segments are free.

A replacement thermal sleeve with a flange for a reactor vessel closure head penetration adapter housing. By altering a diameter of the flange, a replacement thermal sleeve can be installed through the narrow diameter of the penetration adapter housing opening from under the reactor vessel head. The flange can be compressible or expandable or the tubular wall of the thermal sleeve can be inserted in longitudinal sections, one at a time, into an opening in the underside of the penetration head adapter and reformed within the opening when fully inserted.

A replacement thermal sleeve with a flange for a reactor vessel closure head penetration adapter housing. By altering a diameter of the flange, a replacement thermal sleeve can be installed through the narrow diameter of the penetration adapter housing opening from under the reactor vessel head. The flange can be compressible or expandable or the tubular wall of the thermal sleeve can be inserted in longitudinal sections, one at a time, into an opening in the underside of the penetration head adapter and reformed within the opening when fully inserted.

A pipe cap assembly for a normally-sealed system includes a pipe cap having a base portion. 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.

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.

A nozzle repair method and a nuclear reactor vessel include: removing a trepanning portion (208) as a connection portion with respect to an in-core instrumentation cylinder (204) in a groove-welding portion (206); removing the in-core instrumentation cylinder (204) from a lower end plate (66); forming a plug attachment opening (211) by removing the groove-welding portion (206); applying a pressing load to the lower end plate (66) by attaching a plug (212) to the plug attachment opening (211); and welding and fixing the plug (212) attached to the plug attachment opening (211). Accordingly, since a repair is easily performed, it is possible to improve the workability and to decrease a repair cost.

A nozzle repair method and a nuclear reactor vessel include: removing a trepanning portion (208) as a connection portion with respect to an in-core instrumentation cylinder (204) in a groove-welding portion (206); removing the in-core instrumentation cylinder (204) from a lower end plate (66); forming a plug attachment opening (211) by removing the groove-welding portion (206); applying a pressing load to the lower end plate (66) by attaching a plug (212) to the plug attachment opening (211); and welding and fixing the plug (212) attached to the plug attachment opening (211). Accordingly, since a repair is easily performed, it is possible to improve the workability and to decrease a repair cost.

A channel baffle structure comprises a pipe, a swing check plate and a driving apparatus, wherein the main part of the swing check plate is located inside the pipe, and the driving apparatus is disposed outside the pipe. A connection structure is used for connecting the driving apparatus and the swing check plate. The check plate can be opened and closed passively by gravity and fluid pressure, but can also be actively opened and closed by the driving apparatus, such that requirements for multiple operating conditions of the channel can be satisfied.