Westinghouse Electric Corporation

Louis J Malandra

Robert E Meuschke

Michael F Hankinson

Robert J Leduc

Leonard P Hornak

Bruce W Bevilacqua

Robert B Salton

Stanley R Spiegelman

Edward F Kowalski

Alex W Harkness

Robert W Beer

Joseph W Richard

Michael L Cognevich

A refueling machine for refueling a pressurized water reactor has a trolley which travels on rails mounted on a transversely movable bridge. The trolley supports a refueling mast which includes an outer mast and two horizontally spaced apart, vertically movable gripper masts disposed within the outer mast. This design permits the machine to safely handle two fuel assemblies simultaneously in order to substantially reduce refueling critical path time. The two gripper masts can be raised, lowered and otherwise operated independently of each other. A partition plate extending through the stationary mast between the two movable gripper masts permits each fuel assembly held in the refueling mast to be independently leak tested.

Refueling machine

An apparatus, which reinforces a shroud that is contained within a reactor vessel, is operable for reinforcement of the shroud in the event of cracking in the shroud. The apparatus comprises a reactor wall positioned surrounding the shroud. A beam is attached to and extends generally axially on the shroud for absorbing the forces generated by the cracking in the shroud, and a radial support is positioned between the beam and the wall of the reactor vessel for transmitting any forces absorbed by the beam to the wall.

Apparatus for reinforcing a reactor vessel core shroud

A nuclear reactor such as a pressurized water reactor has an integrated head package providing structural support and increasing shielding leading toward the vessel head. A reactor vessel head engages the reactor vessel, and a control rod guide mechanism over the vessel head raises and lowers control rods in certain of the thimble tubes, traversing penetrations in the reactor vessel head, and being coupled to the control rods. An instrumentation tube structure includes instrumentation tubes with sensors movable into certain thimble tubes disposed in the fuel assemblies. Couplings for the sensors also traverse penetrations in the reactor vessel head. A shroud is attached over the reactor vessel head and encloses the control rod guide mechanism and at least a portion of the instrumentation tubes when retracted. The shroud forms a structural element of sufficient strength to support the vessel head, the control rod guide mechanism and the instrumentation tube structure, and includes radiation shielding material for limiting passage of radiation from retracted instrumentation tubes. The shroud is thicker at the bottom adjacent the vessel head, where the more irradiated lower ends of retracted sensors reside. The vessel head, shroud and contents thus can be removed from the reactor as a unit and rested safely and securely on a support.

Integrated head package for top mounted nuclear instrumentation

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). Thermocouple electrical connector and control rod drive mechanism coolant air exhaust port access panels (68) (74) are respectively provided within the radiation shield (10), and an emergency water-gas vent line (76) is likewise accommodated by an access panel (78) also defined within the radiation shield (10). The shield (10) is vertically spaced above the closure head (12) so as to define a gap (82) therebetween, and auxiliary hinged shield panels (192) may be secured along the bottom of the shield (110) to close the gap (182).

Reactor vessel head permanent shield

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). The air ducts (140) pass through the seismic support platform (128) and the missile shield plate (134), and a centralized cable connector plate (164), to which all electrical cables from the CRDMS, thermocouples, and control-rod rod-position-indicator coils are routed and connected, is mounted upon the seismic support platform (128) and is interposed between the seismic support platform (128) and the missile shield plate (134). By means of the modular head assembly (110) of the present invention, all of the aforenoted components may be lifted or lowered along with the closure head (112) as one integral unit, all components are physically located within the peripheral envelope of the closure head (112), and existing facilities can be accordingly modified.

Modular head assembly and method of retrofitting existing nuclear

A quick-acting stud tensioner tool for enabling the loosening or tightening of a stud nut on a reactor vessel stud. The tool engages the vessel stud by closing a gripper mechanism around an upper end of the vessel stud upon a transfer of the mass of the tool from a hoist to a support structure surrounding the vessel stud. After the stud has been elongated, the gripper mechanism releases the vessel stud when the mass of the tool is transferred from the support structure surrounding the vessel stud to the hoist.

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McKeesport, PA, United States of America

Louis J Malandra