Westinghouse Electric Corporation

Edward F Kowalski

Leonard P Hornak

Kenneth J Swidwa

Michael F Hankinson

Louis J Malandra

Robert J Leduc

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

Apparatus for transferring, not only the fuel assemblies, but other component assemblies including control-rod assemblies, thimble-plug assemblies, poison assemblies and the like during refueling of a nuclear reactor. The apparatus includes an outer mast for guiding and protecting the component assemblies which are transferred, an inner mast movable vertically within the guiding mast. The inner mast has grippers for engaging and lifting or lowering fuel assemblies. The outer mast has internal grooved rollers along its length. The inner mast is formed at oppositely facing channels held in a rigid assembly by plates to which the channels are secured. Opposite corners formed by the flanges and the webs of the channels penetrate into the grooves of the rollers and the inner mast is guided and held in position by the rollers. The apparatus also includes an elongated tube within the inner mast movable vertically relative to the inner mast. The tube has a grapple or gripper for engaging and lifting or lowering the component assemblies other than the fuel assemblies. The tube is penetrated by an actuator rod which locks the grapple to the component assemblies. The tube is driven upwardly or downwardly by a winch. The tube carries a primary set of lugs. The inner mast has a plate with an opening through which the lugs pass when the tube alone is driven upwardly. The plate carries a pivotal yoke which is movable between a first or closed position in which the yoke extends over the opening and a second or open position when it does not extend over the opening. In the closed position the yoke is engageable by the primary lugs so that when the tube is raised the inner mast is also raised. The tube also has secondary lugs. The inner mast carries a stop engageable by the secondary lugs when the tube is in a vertical position in which it has raised a component assembly within the masts. The engagement of the secondary lugs and plate serves to pull the inner mast into the guiding mast.

Transfer of nuclear reactor component assemblies

A refueling machine for inserting and removing fuel assemblies from a nuclear reactor including a pair of concentrically disposed stationary masts mounted on a movable bridge which spans the containment walls of the reactor. The bridge supports a trolley movable transversely to bridge movement thus providing an arrangement wherein the masts can be precisely positioned over a fuel assembly in the reactor core. A hoist mounted on the outer of the masts supports a vertically movable inner mast of a size sufficient to enclose a fuel assembly. An actuator tube inside the inner mast moves gripper fingers on the bottom thereof into engagement with the top nozzle of a fuel assembly prior to lifting it upwardly out of the reactor core.

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Pittsburgh, PA, United States of America

Edward F Kowalski