Westinghouse Electric Corporation

The United States of America As Represented by the United States

Electric Power Research Institute Incorporated

The United States of America As Represented by the United States Energy

John E Sharbaugh

James D Mangus

Robert B Tupper

Gedney B Brown

Julie M Livingston

Asfandiar K Dhalla

Joseph M Kazan

John Geddes Erbes

William C Ritz

Rolv Hundal

George J Kolsun

William L Fauth, Jr

Daniel S Jones

John J Brennan

James A Weissburg

Wesley L Howarth

A liquid metal nuclear reactor has a sodium tank, having a closed arcuate bottom and upstanding cylindrical wall for containing a reactor core in a pool of liquid metal coolant, which is disposed in a guard tank having a bottom and upwardly extending cylindrical shell, and a support inside the guard tank adjacent the closed bottom of the sodium tank to support the two tanks in spaced relationship to each other. Support legs are also provided about the bottom periphery of the guard tank adapted to rest on a base mat of a reactor cavity. The bottom of the guard tank may be a closed arcuate shape, or the bottom may be a flat bottom wall that rests on the base mat with the cylindrical shell divided into two radially spaced sections, with a pool of lead-bismuth alloy provided on the bottom to seal the spaces between the two shell sections at the lower region thereof. The pool of lead-bismuth alloy provided on the flat bottom wall of the guard tank contacts the bottom of the sodium tank to aid in preheating the same and providing a supporting and dampening effect therefor.

Bottom supported liquid metal nuclear reactor

A liquid metal nuclear reactor has a sodium tank, having a closed arcuate bottom and upstanding cylindrical wall for containing a reactor core in a pool of liquid metal coolant, which is disposed in a guard tank having a bottom and upwardly extending cylindrical shell, and a support inside the guard tank adjacent the closed bottom of the sodium tank to support the two tanks in spaced relationship to each other. The sodium tank has an open top spaced from an overlying closure deck, with the cylindrical shell of the guard tank secured to the closure deck. The support is preferably an inner ledge. Support legs are also provided about the bottom periphery of the guard tank adapted to rest on a base mat of a reactor cavity. The bottom of the guard tank may be a closed arcuate shape, or the bottom may be a flat bottom wall that rests on the base mat with the cylindrical shell divided into two radially spaced sections, with a pool of lead-bismuth alloy provided on the bottom to seal the spaces between the two shell sections at the lower region thereof. A metal barrier may be provided between the guard tank and the reactor cavity side wall to divide the area therebetween into two annular chambers, with a thermal insulation provided on the barrier outside to form the inner chamber into an oven-like chamber.

An improved shut-down heat removal system for a liquid metal nuclear reactor of the type having a vessel for holding hot and cold pools of liquid sodium is disclosed herein. Generally, the improved system comprises a redan or barrier within the reactor vessel which allows an auxiliary heat exchanger to become immersed in liquid sodium from the hot pool whenever the reactor pump fails to generate a metal-circulating pressure differential between the hot and cold pools of sodium. This redan also defines an alternative circulation path between the hot and cold pools of sodium in order to equilibrate the distribution of the decay heat from the reactor core. The invention may take the form of a redan or barrier that circumscribes the inner wall of the reactor vessel, thereby defining an annular space therebetween. In this embodiment, the bottom of the annular space communicates with the cold pool of sodium, and the auxiliary heat exchanger is placed in this annular space just above the drawn-down level that the liquid sodium assumes during normal operating conditions. Alternatively, the redan of the invention may include a pair of vertically oriented, concentrically disposed standpipes having a piston member disposed between them that operates somewhat like a pressure-sensitive valve. In both embodiments, the cessation of the pressure differential that is normally created by the reactor pump causes the auxiliary heat exchanger to be immersed in liquid sodium from the hot pool. Additionally, the redan in both embodiments forms a circulation flow path between the hot and cold pools so that the decay heat from the nuclear core is uniformly distributed within the vessel.

Passive shut-down heat removal system

An entirely passive auxiliary core cooling system for a liquid-metal reactor wherein a path for natural circulation through a radial plenum and radially outermost core assemblies to the heat generating inner core assemblies is provided, the flow being cooled by a totally passive heat exchanger.

Passive reactor auxiliary cooling system

An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment structure base mat so as to insulate the reactor vessel bottom end wall from the containment structure base mat and allow the reactor vessel bottom end wall to freely expand as it heats up while providing continuous support thereof. Further, a deck is supported upon the side wall of the containment structure above the top open end of the reactor vessel, and a plurality of serially connected extendible and retractable annular bellows extend between the deck and the top open end of the reactor vessel and flexibly and sealably interconnect the reactor vessel at its top end to the deck. An annular guide ring is disposed on the containment structure and extends between its side wall and the top open end of the reactor vessel for providing lateral support of the reactor vessel top open end by limiting imposition of lateral loads on the annular bellows by the occurrence of a lateral seismic event.

Nuclear reactor construction with bottom supported reactor vessel

A plenum separator system for separating the hot plenum from the cold plenum and from the reactor vessel wall in a pool-type nuclear reactor. One or more intermediate plena containing substantially stagnant and thermally stratified coolant provide axial separation of the hot and cold plena. A dual pass forced bypass flow through annuli at the upper portion of the reactor vessel wall, in conjunction with the intermediate plenum and an annular gas space adjacent the reactor vessel wall, provide radial separation of the hot plenum and the vessel wall.

Plenum separator system for pool-type nuclear reactors

An electric pipe snubber has an annular housing, fixed to a supporting surface, surrounding a pipe and a plurality of brake means fixed to the housing radially disposed about the pipe, which are biased towards and engage a serrated section on the pipe, and a means for electromagnetically releasing the brake means to permit axial displacement of the pipe relative to the annular housing. The brake means have teeth on the end thereof which mesh with the serrations on the pipe. A pipe support system using a series of the electric pipe snubbers along a length of pipe has a control means which releases the brakes of one of the series of the snubbers while the remainder of the series restrain the pipe from axial displacement.

Electric pipe snubber

Arrangements for sealing cover gas from the clearance spaces among primary vessel head structure components in a liquid metal cooled fast breeder nuclear reactor including a dip seal having a trough and blade respectively suspended from adjacent head structure components, such as rotatable plugs, the trough and blade extending downward to an elevation below the operating level of coolant within the vessel. A vent pipe equalizes pressure during power operation among the separate cover gas regions formed by the dip seal.

Nuclear reactor dip seal

A combination seal and bearing arrangement for use in a nuclear reactor including a vessel and vessel cover is disclosed herein. The vessel cover itself includes at least one rotatable plug which serves to perform certain position related functions within the reactor vessel and the combination seal and bearing arrangement is provided for sealing the annular opening around the rotation plug while, at the same time, providing a bearing support for the latter.

Seal and bearing arrangement for use in a nuclear reactor

Apparatus for insulating hot sodium in a reactor vessel in a pool-type nuclear reactor. The apparatus includes a flow isolated plenum in the reactor vessel for holding a stagnant quantity of sodium. The flow isolated plenum is located between a second plenum for holding hot sodium and the structural load bearing members of the reactor. The flow isolated plenum forms a thermally insulating field barrier between the hot sodium and the structural members.

Apparatus for insulating hot sodium in pool-type nuclear reactors

In a light water reactor system using the thorium-232 -- uranium-233 fuel system in a seed-blanket modular core configuration having the modules arranged in a symmetrical array surrounded by a reflector blanket region, the seed regions are disposed for a longitudinal movement between the fixed or stationary blanket region which surrounds each seed region. Control of the reactor is obtained by moving the inner seed region thus changing the geometry of the reactor, and thereby changing the leakage of neutrons from the relatively small seed region into the blanket region. The mechanical design of the Light Water Breeder Reactor (LWBR) core includes means for axially positioning of movable fuel assemblies to achieve the neutron economy required of a breeder reactor, a structure necessary to adequately support the fuel modules without imposing penalties on the breeding capability, a structure necessary to support fuel rods in a closely packed array and a structure necessary to direct and control the flow of coolant to regions in the core in accordance with the heat transfer requirements.

Growing community of inventors

Bullskin, PA, United States of America

John E Sharbaugh