Abstract: A pressurized water reactor nuclear containment radiation shield which surrounds the upper portion of a pressure vessel in an ice condenser containment. The vertical walls of the neutron shield are formed in vertical sections with the lower and upper sections operable during outages, to open to promote air flow cooling along the walls in the vicinity of the vessel head.

Abstract: A pressurized water reactor nuclear containment radiation shield which surrounds the upper portion of a pressure vessel in an ice condenser containment. The vertical walls of the neutron shield are formed in vertical sections with the lower and upper sections operable during outages, to open to promote air flow cooling along the walls in the vicinity of the vessel head.

Abstract: A reactor pressure vessel supports the flanges of a core barrel assembly and an upper support plate. These flanges have aligned holes for diverting inlet coolant water to the vessel head for cooling the head. The aligned holes have different cross-sectional areas for controlling unexpected backflow of coolant water from the vessel head around the periphery of the upper support plate.

Abstract: A reactor pressure vessel supports the flanges of a core barrel assembly and an upper support plate. These flanges have aligned holes for diverting inlet coolant water to the vessel head for cooling the head. The aligned holes have different cross-sectional areas for controlling unexpected backflow of coolant water from the vessel head around the periphery of the upper support plate.

Abstract: A reactor pressure vessel supports the flanges of a core barrel assembly and an upper support plate. These flanges have aligned holes for diverting inlet coolant water to the vessel head for cooling the head. The aligned holes have different cross-sectional areas for controlling unexpected backflow of coolant water from the vessel head around the periphery of the upper support plate.

Abstract: An integrated head assembly for a nuclear reactor pressure vessel includes a closure head with CRDM assemblies extending upwardly from the head. A CRDM seismic support disposed above the closure head provides lateral support for the CRDM assemblies. The seismic support also has air flow holes which communicate with the interior of a shroud enclosing the CRDMs and extending upwardly from the closure head to the seismic support. The shroud has an air port in direct air flow communication with the surrounding atmosphere so that the closure head, shroud and seismic support define an air flow passageway directly communicating with the surrounding atmosphere via the air port and without the extensive ductwork and, therefore, with substantially less power.

Abstract: A nuclear reactor containment arrangement has a permanent seal ring across the thermal expansion gap defined by the reactor vessel wall and the containment wall. The seal ring allows for lateral translation of the reactor vessel, in addition to radial and axial expansion and contraction. The seal ring features an outer attachment arrangement characterized by a radially corrugated cylinder extending vertically between two annular Belleville plates having different diameters. The corrugations of the cylinder extend longitudinally between the cylinder edges, and flex during lateral movement of the reactor vessel relative to the containment wall. The Belleville plates accommodate axial expansion and contraction of the vessel, and an inner attachment arrangement accommodates radial expansion and contraction.

Abstract: Self-locking plug for plugging a hole defined by a surrounding structure, which structure may be a nuclear power reactor pressure vessel core barrel flange. When the hole is plugged, transient hydraulic forces generated in the pressure vessel will tend to force the plug from the hole. The plug includes a plug body sized to be disposed in the hole and a locking member pivotally connected to the plug for locking the plug body to the flange, so that the plug is not inadvertently forced from the hole by the transient hydraulic forces. A cam, which is capable of engaging the locking mechanism for outwardly pivoting the locking mechanism, is slidably connected to the plug body. A movable piston is connected to the cam for driving the cam into engagement with the locking mechanism. Moreover, the locking mechanism pivots to engage the flange as the cam engages the locking member. A ram, which is also connected to the plug body, is provided to ram the plug body into the hole for snugly plugging the hole.

Abstract: A remotely operated device which attaches to an existing internals lifting rig to safely lift and transport nuclear reactor internals structures. The device includes a grapple assembly uniquely formed to maximize the effective bearing surface of an annular shoulder disposed on the grapple assembly to engage the internal structure. The annular shoulder comprises a first outer diameter, the annular shoulder defining a second outer diameter disposed thereabove. The grapple assembly comprises a plurality of fingers circumferentially disposed about an actuator rod which has a diameter essentially equal to a first inner diameter of the grapple assembly. The lower end of the grapple assembly has a second inner diameter smaller than the first and axially adjacent to the annular shoulder.

Abstract: A radiation shield (10) is comprised of three, equiangularly extending, arcuate sections (14) which are secured to the nuclear reactor pressure vessel closure head (12) so as to annularly surround the nuclear reactor control rod drive mechanisms (26) and thereby prevent radiation emanating from the mechanisms (26) from reaching maintenance personnel who may be operatively working within the peripheral section (20) of the closure head. The shield sections (14) are bolted together by fasterners (18) and are secured to closure head lift lugs (30) by means of mounting brackets (38) and transversely extending pins (36). Clevis assemblies (34) are also pinned to the mounting brackets (38) and lift lugs (30), and lift rods (32) are threadedly engaged with the clevis assemblies (34). In this manner, when the closure head (12) is lifted from its associated pressure vessel, the radiation shield (10) remains with the closure head (12).

Abstract: An annular ring seal for establishing a permanent seal across an annular thermal expansion gap defined between a peripheral wall of a nuclear reactor vessel and a containment wall, which containment wall is spaced apart and surrounds the peripheral wall of the reactor vessel, which collectively define a nuclear reactor containment arrangement. The annular ring seal comprises an annular ring plate having an outer peripheral surface affixed to the containment wall and an inner peripheral surface proximate the reactor vessel; and a flexure member having an annular base plate, which sealingly engages and is affixed to the annular ring plate near the inner peripheral surface thereof, and having a leg which is joined to and extends upwardly from the annular base plate and which is affixed to the peripheral wall of the reaction vessel to thereby seal the annular thermal expansion gap.

Abstract: A modular head assembly (110) for a nuclear reactor pressure vessel includes a closure head (112) having control rod drive mechanisms (116) mounted therein and projecting thereabove. Cooling baffles (118) provide air paths for cooling air for the CRDMs (116), and a lower air manifold (120) is fluidically connected to the cooling baffles (118) as well as to vertically upwardly extending air ducts and manifolds (136, 138, 140). Axial flow exhaust fans (126) are fluidically connected to the ducts (140) through means of plenum chambers (162) with the latter mounted upon a missile shield plate (134). The missile shield plate (134) is fixedly mounted upon closure head lift rods (144) as is a seismic support platform (128).

Abstract: Shielding for technicians working around a nuclear reactor during the refueling process is provided by permanently mounting a shield support around the reactor shroud and temporarily hanging shielding members such as lead panels from the support. The shield support includes a permanent rail encircling the shroud and swingout arms which are pivotably mounted to the permanent rail. During use the shielding members are positioned adjacent the swingout arms by a stud tensioner hoist, and the swingout arms are pivoted outward to receive the shielding members. When installed, the edges of the shielding members overlap.

Abstract: A hydrostatic seal for sealing an annular gap between two flat substantially horizontal coplanar surfaces, and particularly a gap in a nuclear reactor cavity which comprises a generally flat annular plate of a width sufficient to span the gap between the two surfaces, compressible annular sealing rings or gaskets disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces when a downward force is exerted on the plate, and a plurality of fastening arrangements, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap and exert a downward force on the plate.