Abstract: A device and method for stabilizing a dryer assembly in a reactor pressure vessel of a nuclear reactor including a spring assembly dimensioned and positioned within the reactor pressure vessel for applying a stabilizing force to the dryer assembly relative to the reactor pressure vessel.

Abstract: A device and method for stabilizing a dryer assembly in a reactor pressure vessel of a nuclear reactor including a spring assembly dimensioned and positioned within the reactor pressure vessel for applying a stabilizing force to the dryer assembly relative to the reactor pressure vessel.

Abstract: A remotely installable piping support attachment assembly employs a T-bolt type fastener for clamping a relatively smaller instrumentation pipe, e.g., the jet pump sensing line, to the wall of an adjacent structure. The attachment assembly includes a T-bolt, a split pipe clamp support, a ratchet nut with peripheral ratchet teeth, and a ratchet lock washer. When the nut is tightened on the threaded shank of the T-bolt, a top plate and an anchor of the split pipe clamp support are pressed together to clamp the jet pump sensing line therebetween. The top plate is defined by an L-beam folded spring plate comprised of first and second plate parts disposed generally in parallel and joined at a living hinge flex joint so that said plate parts each have a free end edge remote from said flex joint, the free end edges being spaced apart to define a gap therebetween without preload.

Abstract: The tie rod repair apparatus includes a tie rod secured at its upper end to the shroud flange at the top of the shroud. The lower end of the tie rod passes through an opening in the shroud support plate without imposing a load on the plate. The lower end of the tie rod is anchored to the lower end of the core shroud support cylinder such that the compressive load path exerted by the tie rod to restrain the cracked shroud passes directly through the shroud support cylinder and the assembly of shroud cylinders bypassing the shroud support plate.

Abstract: A device and method for stabilizing a dryer assembly in a reactor pressure vessel of a nuclear reactor including a spring assembly dimensioned and positioned within the reactor pressure vessel for applying a stabilizing force to the dryer assembly relative to the reactor pressure vessel.

Abstract: A remotely installable piping support attachment assembly employs a T-bolt type fastener for clamping a relatively smaller instrumentation pipe, e.g., the jet pump sensing line, to the wall of an adjacent structure. The attachment assembly includes a T-bolt, a split pipe clamp support, a ratchet nut with peripheral ratchet teeth, and a ratchet lock washer. When the nut is tightened on the threaded shank of the T-bolt, a top plate and an anchor of the split pipe clamp support are pressed together to clamp the jet pump sensing line therebetween. The top plate is defined by an L-beam folded spring plate comprised of first and second plate parts disposed generally in parallel and joined at a living hinge flex joint so that said plate parts each have a free end edge remote from said flex joint, the free end edges being spaced apart to define a gap therebetween without preload.

Abstract: A piping support wedge apparatus for a jet pump in a nuclear reactor is provided. In an exemplary embodiment, the wedge apparatus includes a first tapered wedge segment having a first end portion and a second end portion and a second tapered wedge segment having a first end portion and a second end portion. The first and second wedge segments are joined at the first ends portions to form a substantially U-shaped body. The wedge apparatus also includes a slot defined by an area between the first and second wedge segments and extending from the first end portions to the joined second end portions of the wedge segments.

Abstract: A piping support wedge apparatus for a jet pump in a nuclear reactor is provided. In an exemplary embodiment, the wedge apparatus includes a first tapered wedge segment having a first end portion and a second end portion and a second tapered wedge segment having a first end portion and a second end portion. The first and second wedge segments are joined at the first ends portions to form a substantially U-shaped body. The wedge apparatus also includes a slot defined by an area between the first and second wedge segments and extending from the first end portions to the joined second end portions of the wedge segments.

Abstract: Methods for cutting a labyrinth seal in a nuclear reactor jet pump assembly are described. In one embodiment, the method includes removing an irradiated jet pump inlet mixer from the jet pump assembly, positioning the jet pump inlet mixer underwater, and cutting at least one circumferential groove in an inlet mixer outside surface.

Abstract: Methods for cutting a labyrinth seal in a nuclear reactor jet pump assembly are described. In one embodiment, the method includes removing an irradiated jet pump inlet mixer from the jet pump assembly, positioning the jet pump inlet mixer underwater, and cutting at least one circumferential groove in an inlet mixer outside surface.

Abstract: A remotely installable piping support device includes a pair of mating tapered wedge segments extending from lever arms connected with a spiral wound spring. The spring is machined integrally with the left lever arm and has a projecting center square drive hub with an internal mounting thread. The right lever arm has an internal square drive which mates with the drive hub. A bolt engages the drive hub and secures the lever arms together. The spring preload on the wedge acting across the shallow angled wedge surfaces maintains rigid contact between jet pump components and takes up the clearance from wear during operation.

Abstract: A method for applying a lateral support load to a jet pump slip joint. The method includes positioning an ovalization device around the diffuser and actuating the ovalization device to apply a predetermined load to the slip joint which creates an oval deformation of the diffuser. The force applied by the ovalization device creates a plastic strain in the diffuser wall which permits the diffuser to maintain an oval shape, and an elastic strain in the wall of the inlet mixer. The elastic deflection of the inlet mixer which is restrained from its original shape applies a lateral preload force to the diffuser at the area where the diffuser has a reduced diameter due to the oval deformation. This lateral preload force maintains a rigid contact between the inlet mixer and the diffuser collar to prevent oscillating motion and suppress FIV.

Abstract: A seal apparatus for a jet pump slip joint in a boiling water nuclear reactor pressure vessel, in an exemplary embodiment, includes a split seal ring and a segmented diaphragm spring engaging the split seal ring at an inner circumference of the diaphragm spring. The diaphragm spring includes a plurality of latch assemblies spaced circumferentially around an outer circumference. A plurality of slots, spaced circumferentially around the inner circumference, extend from the inner circumference to the support portion. Each latch assembly includes a latch bolt extending through and threadendly engaging a corresponding latch bolt opening in the diaphragm spring. Each latch bolt includes a head and a plurality of ratchet teeth spaced around the periphery of the latch bolt head. A locking spring is positioned to engage the ratchet teeth of the latch bolt head. The latch assembly further includes a latch arm coupled to the latch bolt. The latch arm includes a slot sized to receive a diffuser guide ear.

Abstract: A clamp assembly for a jet pump sensing line adjacent a jet pump within a nuclear reactor pressure vessel. The jet pump sensing line includes a support block. The clamp assembly includes a clamp body, a clamp member coupled to the clamp body, and a slide member coupled to the clamp body. The clamp assembly further includes a clamp bolt, a swing arm bolt, and a swing arm coupled to the slide member. The swing arm and the slide member are sized to receive and secure the sensing line and the clamp member. The clamp member and the clamp body are sized to secure the clamp assembly to the jet pump.

Abstract: A method for applying a lateral support load to a jet pump slip joint. The method includes positioning an ovalization device around the diffuser and actuating the ovalization device to apply a predetermined load to the slip joint which creates an oval deformation of the diffuser. The force applied by the ovalization device creates a plastic strain in the diffuser wall which permits the diffuser to maintain an oval shape, and an elastic strain in the wall of the inlet mixer. The elastic deflection of the inlet mixer which is restrained from its original shape applies a lateral preload force to the diffuser at the area where the diffuser has a reduced diameter due to the oval deformation. This lateral preload force maintains a rigid contact between the inlet mixer and the diffuser collar to prevent oscillating motion and suppress FIV.

Abstract: A remotely installable piping support device includes a pair of mating tapered wedge segments extending from lever arms connected with a spiral wound spring. The spring is machined integrally with the left lever arm and has a projecting center square drive hub with an internal mounting thread. The right lever arm has an internal square drive which mates with the drive hub. A bolt engages the drive hub and secures the lever arms together. The spring preload on the wedge acting across the shallow angled wedge surfaces maintains rigid contact between jet pump components and takes up the clearance from wear during operation.

Abstract: A clamp apparatus for a jet pump slip joint in a boiling water nuclear reactor pressure vessel includes a C-yoke having an arcuate main portion, an engagement portion extending from a first end of the main portion, and a locking preload portion extending from a second end of the main portion. The engagement portion includes an engagement slot configured to receive a diffuser guide ear. The locking portion includes a threaded clamp bolt opening extending therethrough, and a clamp bolt threadedly engaging and extending through the clamp bolt opening. The clamp bolt includes a locking collar and a plurality of ratchet teeth spaced around the periphery of the locking collar. A locking spring engages the ratchet teeth of the clamp bolt to lock the clamp bolt in place and prevent the bolt from loosening.

Abstract: An apparatus for repairing the core shroud of a nuclear reactor having one or more cracked vertical seam welds. The repair involves machining two holes in the shroud on opposing sides of the cracked vertical seam weld and then attaching two flexible links on the inside and outside of the shroud wall by means of two shear bolts inserted in the machined holes. The flexible links bridge the cracked vertical weld seam. Multiple link assemblies can be placed along the length of a crack. The links are made of an alloy having a coefficient of thermal expansion less than the coefficient of thermal expansion of the shroud material. The links are installed while the reactor is shutdown. When the reactor returns to operation, the consequent temperature rise causes the shroud section being bridged by the links to expand more than the links expand. As a result the links exert a circumferential compressive load across the crack in the vertical seam weld.

Abstract: An auxiliary wedge apparatus configured to couple to the restrainer bracket of a jet pump assembly is described. In one embodiment, the auxiliary wedge apparatus includes a support block configured to couple to the restrainer bracket, and a wedge configured to slidingly couple to a wedge channel in the support block, and to engage the inlet mixer to restore a tight rigid fit-up of the jet pump components. The support block includes a wedge channel having tongues depending from the parallel sides of the channel and a hook shaped portion configured to receive the restrainer bracket. The support block also includes a lock screw to couple the support block to the restrainer bracket. The wedge includes grooves in the parallel sides of the wedge configured to slidingly engage the tongues extending in the wedge channel.

Abstract: A wedge locking support apparatus that applies a downward preload force to a jet pump inlet mixer gravity wedge and is remotely installable without disassembly of the jet pumps is described. The downward force supplied by the wedge locking support apparatus supplements the force supplied by the weight of the gravity wedge and improves the lateral support provided to the inlet mixer by the gravity wedge. The wedge locking support apparatus includes an upper leaf spring assembly configured to engage the gravity wedge bracket, a lower leaf spring assembly slidably coupled to the upper leaf spring assembly and configured to engage the top of the wedge, and a jack bolt coupled to the upper and lower assemblies.