Abstract: Process and apparatus are disclosed for removing and replacing the hold down beams of fluid circulating jet pumps mounted in a nuclear reactor. The disclosed process and apparatus are operable from a position such as the refueling bridge remote from the reactor and while the refueling cavity surrounding the reactor is flooded with moderator fluid.

Abstract: Process and apparatus are disclosed for removing and replacing the hold down beams of fluid circulating jet pumps mounted in a nuclear reactor. The disclosed process and apparatus are operable from a position such as the refueling bridge remote from the reactor and while the refueling cavity surrounding the reactor is flooded with moderator fluid.

Abstract: A temporary support structure for supporting a lower internals assembly above the reactor vessel during inspection and/or maintenance thereof. A support bracket is bolted to the reactor vessel flange at the vessel head stud closure holes. A pivotally mounted arm, upon the top surface of which the internals rest, is attached at one end to the support bracket and projects radially inwardly therefrom. A compliant foot depends from the bottom of the opposite end of the arm and engages the vessel internals support ledge to provide a secure support structure for the internals assembly. An alignment bracket on the arm aligns the internals with the support. Four such structures are installed around the circumference of the vessel flange while the internals are within the reactor vessel. The structure allows the lower internals to be quickly removed from the interior of the reactor vessel and placed on the temporary supports.

Abstract: A nuclear reactor having a remotely removable and replaceable thermal insulating shield for the head. Access permitting removal and replacement of the head is thus afforded.The thermal insulating shield includes a vertical frame of insulating material of polygonal transverse cross section encircling the head. A top panel of insulating material is mounted on the top of the frame pivotal by remote actuation between a horizontal position and a retracted position which may be vertical. In the horizontal position, the panels mate to provide thermal shielding for the head.

Abstract: A shield panel for use in a nuclear reactor including a reactor vessel susceptible to embrittlement when bombarded with high energy neutrons and a nuclear reactor core mounted within the reactor vessel, the reactor vessel having a longitudinal axis and an inner surface surrounding the longitudinal axis, and the nuclear core emitting high energy neutrons which impinge on the inner surface of the reactor vessel. The shield panel includes a canister which contains a completely enclosed interior space and which is mountable between the inner surface of the reactor vessel and the nuclear core in a region wherein the reactor vessel is susceptible to a higher rate of embrittlement than the remaining portion of the vessel when bombarded with high energy neutrons emitted from the nuclear core, and a substance consisting essentially of a heavy metal and hydrogen filling the interior space of the canister.

Abstract: A handling tool for selectively removable cruciforms employed in ice baskets of the type employed with nuclear power generator systems. The tool includes clamping means for engaging a compressible central portion of the removable cruciform to retract same inwardly and permit moving same, in a horizontal orientation, throughout the axial height of the interior of the ice basket. When at a desired elevation, selective actuating means moves previously retracted guide means to an extended or projected position for engaging a retaining ring of the ice basket and supporting the tool on the ring. The clamping means is selectively actuated to the disengaged position for releasing the cruciform whereupon the same expands, projecting legs associated therewith radially outwardly and engaging the retaining ring, to support the cruciform on the ring. The tool may thereafter be removed.

Abstract: Removable cruciforms are selectively installed at predetermined, spaced elevations within ice baskets associated with a nuclear power system, each ice basket having a generally cylindrical sidewall with plural, annular retaining rings secured therein at predetermined, spaced elevations, each cruciform being installed at predetermined, axially displaced elevations, engaging a corresponding annular retaining ring. Each cruciform comprises a pair of brackets joined together between parallel base portions by respective support plate assemblies and slide plates in telescoping, sliding relationshp, defining with the base portions, a spring housing of generally square configuration within which a generally C-shaped spring is received. A pair of legs extends integrally from the longitudinal edges of the base portion of each bracket, angularly disposed so as to extend radially within the ice basket.

Abstract: A reactor vessel stud cleaning machine for cleaning reactor studs. The stud is supported horizontally by a pair of roller carriage assemblies inside of a closed chamber. At least one roller carriage assembly has rollers driven by a stud drive motor which cause the stud to rotate. As the stud rotates, a spray nozzle traverses the length of the stud spraying a mixture of high pressure water and abrasive onto the stud. The spent water and abrasive is drained from the enclosure and pumped through a separator funnel and filter bank to remove solids. The filtered water is returned to a supply tank for reuse. The stud rotation speed and spray nozzle traverse speed the variable as in the water pressure and rate of abrasive injection.

Abstract: In a steam generator an ultrasonic probe is used to measure the accumulation of sludge between the tubes. A ribbon-like probe carrier is fed into the vessel and deflected by a carriage placed in alignment with a lane of tubes at 90.degree., the probe head being advanced in the lane to measure vertically and sideways the distance to the surface of the sludge. The probe carrier consists of two steel tapes held face-to-face by a plastic tube which has been heat shrunk. The conductors for the transducers are contained in the space between concave tapes. An adaptor mounted at the end of the probe carrier is amovably connected to the probe head. Probe head, adaptor and probe carrier are sealed so that measurement can be conducted inside the steam generator supposedly filled with water.

Abstract: An eddy current probe for mapping holes within a tube sheet of a steam generator, having a first coil (12) positioned at the top of the probe (10) with its axis coincident with the axis of the probe. A first coil pair (14 and 16) is arranged along a common axis perpendicular to the axis of the probe below the first coil (12) and is situated a distance from and on either side of the axis of the probe. A second pair of eddy current coils (18 and 20) is positioned along a common axis perpendicular to the axis of the probe and the axis of the first coil pair with the respective coils of the second pair located on either side of and spaced from the probe axis. Each of the respective coils are arranged to be separately excited by an alternating current source with the respective coil pairs coupled in opposition in corresponding balanced bridge arrangements.

Abstract: Method and apparatus for expeditious installation of bottom-supporting and side-anchoring blocks for a tube and tube sheet bottom repair apparatus in the interior of the channel head of a steam generator at one side of the divider plate in a nuclear power plant, involving use of special tools and fixtures for location and welding of such blocks in position by use of information derived from measurement of the extent and direction of tilt of the tube sheet bottom from a purely horizontal attitude.

Abstract: Apparatus that is assembled quickly inside a portion of a channel head of a steam generator and is capable of performing various repair and inspection operations on all of the tubes and the tubesheet in that portion of the channel head.