General Electric Company

Larry E Fennern

Craig Delany Sawyer

Perng-Fei Gou

Russell M Fawcett

Roy C Challberg

Charles W Dillmann

Momtaz Mahdi Aburomia

Russell L Crowther

Charles W Relf

Wayne Marquino

Richard A Ose

Kenneth V Walters

Robert E Brown

Gary I Borchardt

Steven A Hucik

Li C Hsu

Mark W Siewert

John C Walther

Steven R Specker

Bennett J Gitnick

Harold A Careway

Daniel R Wilkins

Nilkanth T Patel

In an embodiment of the present invention, the core of a nuclear reactor includes a plurality of fuel cells and a plurality of large control rods. Each large control rod is about two times the width of a conventional control rod and includes four control rod blades extending radially from a central portion and arranged at right angles to each other. The blades define four fuel bundle receiving channels. The core is configured so that the control rods are-arranged in a plurality of staggered rows with four fuel bundles in each receiving channel.

Core configuration for a nuclear reactor

A compact metal containment vessel, for a boiling water nuclear reactor, includes in one exemplary embodiment, a bottom head, a removable top head, and a substantially cylindrical sidewall extending from the bottom head to the top head. The bottom head, top head and cylindrical sidewall define a containment cavity sized to receive and enclose a reactor pressure vessel. The containment vessel has a pressure rating of at least about 50 atmospheres atm.

Modular reactor containment system

The present invention, in one form, is a natural circulation reactor having, in one embodiment, a layer of high aluminate cement concrete disposed between an uninsulated steel liner and a prestressed concrete reactor vessel. The prestressed concrete reactor vessel includes a concrete shell having a cavity therein. The steel liner is positioned in the cavity and spaced from the concrete shell so that an insulating chamber is formed between the steel liner and the concrete shell. The insulating chamber is filled with high aluminate cement concrete which is configured to substantially insulate the concrete shell from the steel liner and to transfer loads such as pressure from the liner to the concrete shell.

Modified large natural circulation reactor

Fuel bundle and control rod assemblies for a nuclear reactor are described. In one embodiment of the apparatus, the nuclear reactor includes several conventional size fuel bundles and at least one large control rod. The large control rod includes four fuel bundle receiving channels, and each such channel is sized to receive four conventional size fuel bundles.

Fuel bundle and control rod assembly for a nuclear reactor

A nuclear reactor including a heat pipe for transferring heat from the reactor pressure vessel to a steam supply vessel is described. More particularly, in one embodiment, the heat pipe includes an evaporator section positioned in the reactor vessel, a condenser section positioned in the steam supply vessel, and an adiabatic section extending between and in flow communication with the evaporator section and the condenser section. The adiabatic section of the heat pipe includes a substantially cylindrical outer sleeve and a substantially cylindrical inner sleeve. An annulus region is formed between the inner and outer sleeves and the annulus region is in flow communication with the steam supply vessel. An insulating layer covers an inner wall of the outer sleeve. A substantially annular wick member is positioned adjacent an inner wall of the inner sleeve, and a steam path is defined by an inner face of the wick member.

Nuclear reactor heat pipe

A nuclear reactor having a pressure vessel which is open at the top. The open top of the pressure vessel is closed by a steel dome. A containment, which is open at the top, extends upward from and is joined to the top of the pressure vessel and has an open containment head at the top thereof. The open top of the containment is closed by a steel dome, thereby forming a containment well bounded laterally by the containment, on the bottom by the vessel closure and on the top by the containment closure. The pressure vessel can be a steel-lined prestressed concrete vessel, while the containment is formed by an extension of the prestressed concrete vessel. Alternatively, the pressure vessel and the containment are parts of a unitary steel vessel. Isolation valves are installed on each penetration pipeline to isolate the system in the event of a loss-of-coolant accident. An isolation valve located external to the pressure vessel and the portion of the pipeline between that external isolation valve and the interior of the pressure vessel are encased in guard piping. The space between the pipeline and the guard piping is pressurized and monitored to detect any leak in either the pipeline or the guard piping.

Boiling water reactor with compact containment and simplified safety

A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives. The control rods are selectively withdrawn upwardly from the core and inserted downwardly into the core by the control rod drives, which also are effective for selectively releasing the control rods for allowing gravity to insert the control rods into the core.

Boiling water reactor including split control rod drives

A reactor core with each fuel rod surrounded by an individual cylindrical channel is disclosed. This individual channel on each fuel rod provides thermal hydraulic and heat transfer advantages to enable all fuel rods within the fuel bundle to uniformly approach their own thermal limits. The preferred fuel rod pitch is a triangular pitch between the individual fuel rods as they are discretely surrounded by their own channel. The new triangular geometry provides for more uniform (flat) power distributions within all fuel rods--and hence all groups of fuel rods. Bypass flow is introduced uniformly between the fuel rod channels, rather than heterogeneously in the channel gap and water rods as in present BWR fuel designs. Individual fuel rod channels can be orificed differently, as required, to match inlet flow to fuel rod power output to maintain uniformity between all fuel rods as they approach their respective thermal limits. Gaps between bundles can be eliminated, or at least minimized, yielding even higher power density. Spacers with flow diverting structure vanes are applied within the fuel rod channel to limit relative displacement between the channel wall and fuel rod cladding and to serve as turbulent flow promoters.

Fuel design for high power density boiling water reactor

A recirculation system for driving reactor coolant water in a downcomer within a reactor pressure vessel includes a jet pump disposed in the downcomer and having a suction inlet at the top thereof and an outlet at the bottom thereof. A reactor internal pump is joined directly to the pressure vessel at an access nozzle thereof and includes a housing sealingly joined to the access nozzle, and in serial flow communication an inlet channel, an impeller, an outlet channel, and an injector nozzle. The inlet channel carries coolant water from the pressure vessel to the impeller which pressurizes the coolant water and returns it through the outlet channel and the injector nozzle for injection into the jet pump inlet. The water injected from the internal pump into the jet pump drives the jet pump for effecting recirculation flow within the pressure vessel.

Combined jet pump and internal pump rercirculation system

A reactor building assembly includes a pressure vessel within a containment vessel surrounded in turn by first and second enclosures defining respective first and second chambers. A method of operation includes channeling fresh air downwardly by gravity through the second chamber and then channeling the fresh air laterally through the first enclosure adjacent to the bottom thereof and into the first chamber. The air is then channeled upwardly by natural buoyancy through the first chamber for cooling the first chamber and mixing with stale air therein. The stale air is then discharged from the first chamber upwardly through the top of the first enclosure to the environs. A building inlet is disposed at the second enclosure top for receiving the fresh air, a building outlet is disposed at the top of the first enclosure for discharging the stale air, and a transfer duct is disposed through the first enclosure adjacent to the bottom thereof for selectively joining in flow communication the first and second chambers for allowing natural convection circulation of the fresh air downwardly through the second chamber, laterally through the transfer duct, and upwardly through the first chamber.

Reactor building assembly and method of operation

An expanded reactor core capacity is achieved within the constraints imposed by the diametric extent of the current advanced boiling reactor (ABWR). This enhanced core capacity is achieved through the utilization of a scalloped shroud structure in conjunction with modified control rod designs. The core diameter is expanded toward the reactor vessel interior wall to establish a minimum distance therebetween representing a minimum value thereof avoiding neutron fluence induced vessel embrittlement. The control rods servicing peripheral fuel assemblies are configured having either a T-shaped blade configuration or an L-shaped blade configuration depending upon the parallel orientations of the peripheral fuel assemblies.

Boiling water reactor with expanded core diameter

Fuel management in a boiling-water nuclear reactor involves arranging fuel bundles in upper and lower matrices of the reactor core. During a refueling operation, some bundles in the upper matrix are removed and retired, while fresh bundles are inserted in the lower matrix and some bundles originally in the lower matrix are transferred to the upper matrix. In the transfer, fuel bundles are inverted so that included fuel rods in the lower matrix have their plenums oriented downward, while fuel rods in the upper matrix have their plenums oriented upward. This method provides greater flexibility in repositioning fuel bundles for longer burnups and lower high-level waste. In particular, problems with axial spectral variations in neutron flux can be compensated for using the disclosed refueling procedure.

Bi-level fuel management method for boiling-water nuclear reactor

A nuclear reactor with a recirculating heat transfer fluid has a bi-level core which provides enhanced flexibility in fuel arrangement. The bi-level core includes a first core, a plurality of steam separators disposed above the first core, and a second core disposed above the steam separators all inside a single pressure vessel. The steam separators receive a steam and water mixture from the first core and separate the water from the steam. The separated steam is channeled to the second core which cools the second core resulting in the generation of superheated steam. Preferably, fuel bundles of the second core are arranged in vertical alignment with fuel bundles of the first core. This permits a fuel bundle of the first core to be accessed by removing only the adjacent fuel bundle of the second core. During refueling operations, fuel bundles can be shifted from one core to the other, providing additional flexibility in arranging units at various states of burnup. The bi-level core allows fuel to be initially positioned in the second core for conversion of fertile fuel to fissile fuel, and then repositioned to the first core for more complete axial burnup. The steam separators disposed between the first and second cores control the quality of steam channeled into the second core, and allow any crud to remain in solution in the separated water for being removed without buildup in the cores during operation.

Bi-level reactor including steam separators

A method for affecting neutron spectral shift in a reactor core includes providing a liquid poison in a hollow control blade extending into the core, displacing the liquid poison with a first fluid for obtaining a hard neutron spectra during a beginning interval of the core fuel cycle for converting fuel, and then increasing moderating ratio for obtaining a soft neutron spectra during an end interval of the cycle for burning the converted fuel. An exemplary apparatus for practicing the method displaces the liquid poison in the control blade with the first fluid for obtaining the hard neutron spectra. The first fluid may be either replaced, displaced, or added to by a second fluid having a second moderating ratio for obtaining the soft neutron spectra.

Liquid affected spectral shift reactor

A fuel bundle of square cross section and standard vertical dimension is disclosed. The fuel bundle includes a matrix of upstanding vertical rods, a lower tie plate for supporting the matrix of vertical rods and permitting the inflow of liquid moderator coolant (preferably light water), and upper tie plate for holding the matrix of vertical fuel rods upright and permitting the outflow of liquid and vapor moderator coolant (water and steam), and a preferably square sectioned channel extending between the tie plate for confining the flow path between the tie plate around the fuel bundle. The novel characteristics of the invention is the introduction of a corresponding matrix of water rods (cylindrical rods with liquid phase water flow) positioned between the fuel rods, as opposed to the current practice of using or displacing a subset of fuel rods with large central water rod(s) for this purpose. This matrix of water rods preferably has each water rod of smaller diameter than the adjoining fuel rods and is dispersed at intervals uniformly in the matrix of fuel rods. This geometry provides for more uniform (flat) power distributions within the bundle, as a result of the greater similarity of the neutron spectrum in the vicinity of the individual fuel rods. This geometry yields increased design margins for MLGHR and MCPR relative to current fuel designs. The design margins can be traded off to permit achievement of higher core power density. The design also results in less negative void coefficients, which improves core stability.

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San Jose, CA, United States of America

Larry E Fennern