Nuclear Reactor Fuel Patents (Class 252/636)
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Patent number: 11276502Abstract: Fuel bundles for a nuclear reactor are disclosed, and in some embodiments include a first fuel element including thorium dioxide; a second fuel element including uranium having a first fissile content; and a third fuel element including uranium having a second fissile content different from the first fissile content. Nuclear reactors using such fuel bundles are also disclosed, including pressurized heavy water nuclear reactors. The uranium having the different fissile contents can include combinations of natural uranium, depleted uranium, recycled uranium, slightly enriched uranium, and low enriched uranium.Type: GrantFiled: October 11, 2017Date of Patent: March 15, 2022Assignee: ATOMIC ENERGY OF CANADA LIMITEDInventors: Mustapha Boubcher, Sermet Kuran, Cathy Cottrell, Robert R. Bodner, Holly Bruce Hamilton, Bronwyn H. Hyland, Benoit Arsenault
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Patent number: 10347383Abstract: A process is provided for preparing a powder of an oxide of at least one metal, each metal having an oxidation number between (III) and (VI). This process comprises successively and in this order: (a) reacting, with a compound comprising a hydroxide, an aqueous solution comprising, for each metal, at least one salt of the cation of said metal, (b) separating the precipitate obtained, (c) contacting the separated precipitate with an organic protic polar solvent, (d) removing the organic protic polar solvent by vacuum drying the precipitate. A process is further provided for manufacturing a pellet of an oxide of at least one metal as well as to a powder and to a pellet obtained according to these processes and to uses thereof.Type: GrantFiled: January 14, 2015Date of Patent: July 9, 2019Assignees: Commissariat a L'Energie Atomique et al Energies Alternatives, Orano CycleInventors: Julien Martinez, Fabienne Audubert, Nicolas Clavier, Nicolas Dacheux
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Patent number: 9181114Abstract: Provided are a mineralizing removal method and apparatus for highly concentrated iodine in radioactive wastewater. According to the present invention, since only a small amount of sludge is discharged as compared to the previous treatment methods, a generation amount of the radioactive waste may be significantly decreased, such that wastewater containing highly or ultra-highly concentrated iodine may also be effectively treated. Further, only iodine may be selectively removed regardless of the presence of competitive anions in the wastewater. Treatment may be performed under a neutral or weak alkaline condition rather than an acidic condition, such that a volatilization of radioactive iodine was fundamentally blocked, and at the time of discharging the wastewater, a neutralization treatment process is not required.Type: GrantFiled: November 5, 2014Date of Patent: November 10, 2015Assignee: Korea Atomic Energy Research InstituteInventors: Seung Yeop Lee, Ji Young Lee, Jong Tae Jeong, Kyung Su Kim
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Patent number: 8774344Abstract: The invention relates to a new and unique light water reactor (LWR) nuclear fuel pellet configuration formed using tri-isotropic (TRISO) fuel particles suspended in a metal, metal alloy, or ceramic matrix. The new TRISO LWR pellet would have the same dimensions as those of the standard uranium oxide pellet allowing its use without any change to the physical configuration of the reactor vessel, core internals or fuel assemblies. TRISO type fuels have a proven capability for retaining fission products within the confinement boundary created by the coating material. This robustness is expected to reduce or eliminate fuel failure risk and cost. Replacing standard pellets with TRISO LWR fuel pellets with the same, or higher, energy density can potentially extend the operating cycles of LWRs, reduce the number of fuel assemblies replaced in each refueling, reduce the quantity of spent fuel discharged from reactors, lower operating costs, and reduce radioactive waste.Type: GrantFiled: January 11, 2012Date of Patent: July 8, 2014Assignee: Neucon Technology, LLCInventors: Alan H. Wells, Laurence Danese
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Patent number: 8724769Abstract: This invention relates to a method of preparing nuclear fuel including the step of depositing at least two adjacent series of layers (16, 18) around a kernel (12) of fissile material, each series comprising a layer of pyrolytic carbon (16) contiguous with a layer of silicon carbide (18) and each layer (16, 18) having a thickness of at most (10) micrometers, such that alternate layers of (16, 18) of pyrolytic carbon and silicon carbide are deposited around the kernel (12). The invention extends to a nuclear fuel element (10).Type: GrantFiled: March 1, 2005Date of Patent: May 13, 2014Assignee: Pebble Bed Modular Reactor (Proprietary) LimitedInventor: Leszek Andrzej Kuczynski
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Patent number: 8506855Abstract: The present invention includes a composition of LiF—ThF4—UF4—PuF3 for use as a fuel in a nuclear engine.Type: GrantFiled: September 23, 2010Date of Patent: August 13, 2013Assignee: Lawrence Livermore National Security, LLCInventors: Ralph W. Moir, Patrice E. A. Turchi, Henry F. Shaw, Larry Kaufman
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Patent number: 8475747Abstract: A method of processing spent TRIZO-coated nuclear fuel may include adding fluoride to complex zirconium present in a dissolved TRIZO-coated fuel. Complexing the zirconium with fluoride may reduce or eliminate the potential for zirconium to interfere with the extraction of uranium and/or transuranics from fission materials in the spent nuclear fuel.Type: GrantFiled: June 15, 2009Date of Patent: July 2, 2013Assignee: U.S. Department of EnergyInventors: Michael Ernest Johnson, Martin David Maloney
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Patent number: 8293151Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.Type: GrantFiled: June 30, 2010Date of Patent: October 23, 2012Assignee: Westinghouse Electric Company LLCInventors: Edward J. Lahoda, Radu Pomirleanu, Sumit Ray, Lars Hallstadius
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Patent number: 8158962Abstract: A neutron absorbing insert for use in a fuel rack and method of manufacturing the same. In ones aspect, the invention is a neutron absorbing apparatus for insertion into a fuel rack comprising: a sleeve having a first wall and a second wall, the first and second walls forming a chevron shape; and the first and second wall being a single panel of a metal matrix composite having neutron absorbing particulate reinforcement bent into the chevron shape along a crease.Type: GrantFiled: April 29, 2009Date of Patent: April 17, 2012Inventors: Evan Rosenbaum, Thomas G. Haynes, III, Krishna P. Singh
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Publication number: 20120002777Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 20% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.Type: ApplicationFiled: June 17, 2011Publication date: January 5, 2012Applicant: WESTINGHOUSE ELECTRIC COMPANY LLCInventors: Edward J. Lahoda, Radu Pomirleanu, Sumit Ray, Lars Hallstadius
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Publication number: 20120002778Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.Type: ApplicationFiled: June 30, 2010Publication date: January 5, 2012Inventors: Edward J. Lahoda, Sumit Ray, Radu Pomirleanu, Lars Hallstadius
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Publication number: 20110268235Abstract: The present invention generally relates to high-energy composition utilized with reactors and combustors for generating electricity either directly through nuclear or magnetic energy, or indirectly through thermal energy that incorporate the high-energy composition into at least one reactor operable at a temperature greater than 1000 Celsius and containing the composition with at least one co-reactant of Boron-10, with the Boron-10 specifically enabling an at least five percent increase of energy generation and/or efficiency as compared the same reaction without Boron-10. In one embodiment, the present invention relates to the Boron-10 composition within a high-energy reactor operable at a temperature at least 1000 Celsius and a method that applies at least one externally applied force acting upon the Boron-10 portion of the reactor.Type: ApplicationFiled: April 29, 2010Publication date: November 3, 2011Inventor: Michael Gurin
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Publication number: 20110024704Abstract: Compositions are provided that include nuclear fuel. Methods for treating nuclear fuel are provided which can include exposing the fuel to a carbonate-peroxide solution. Methods can also include exposing the fuel to an ammonium solution. Methods for acquiring molybdenum from a uranium comprising material are provided.Type: ApplicationFiled: July 29, 2009Publication date: February 3, 2011Inventors: Chuck Z. Soderquist, Amanda M. Johnsen, Bruce K. McNamara, Brady D. Hanson, Steven C. Smith, Shane M. Peper
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Publication number: 20100314592Abstract: The present invention relates to a method for processing a nuclear fuel comprising a fissile material, SiC and possibly carbon, said method comprising the contacting of said fuel with a chlorine/oxygen mixture at a temperature below 950° C., and more particularly at a temperature between 400 and 900° C., so as to remove the SiC, and the carbon if this is present, from said fuel. The method of the invention makes it possible for example to declad TRISO or BISO nuclear fuel particles, i.e. particles enabling the nuclear fuel to be confined in a sheath or cladding, or to remove an SiC matrix from a fuel having a heterogeneous SiC matrix. The present invention therefore has many applications, especially in the reprocessing of irradiated nuclear fuels.Type: ApplicationFiled: October 23, 2007Publication date: December 16, 2010Applicant: COMMISSARIAT A L'ENERGIE ATOMIQUEInventors: Stephane Bourg, Frederic Peron
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Publication number: 20100303193Abstract: A metal particulate fuel system is described. The metal fuel system may include particulate metal fuel for use in nuclear reactors. The particulate metal fuel may include a plurality of particles of at least one enriched alloy where the particles are compacted into a fuel column. The metal particulate fuel system may also include a cladding and/or a gas-filled plenum.Type: ApplicationFiled: January 29, 2010Publication date: December 2, 2010Applicant: Advanced Reactor Concepts LLCInventor: Leon C. Walters
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Patent number: 7811526Abstract: This invention provides a dripping nozzle device to produce ADU particles with good sphericity, a device for recovering a feedstock liquid to prepare a uniform feedstock liquid, a device for supplying a feedstock liquid to form drops with a uniform volume, a device for solidifying the surfaces of drops so that the drops will not deform easily when they fall onto and hit the surface of an aqueous ammonia solution, a device for circulating an aqueous ammonia solution so that the uranyl nitrate in the drops can be changed to ammonium diuranate completely, to such an extent that uranyl nitrate in the center of each drop is changed to ammonium diuranate, and an apparatus for producing ammonium diuranate particles with good sphericity. The dripping nozzle device is provided with a single vibrator to vibrate nozzles simultaneously. The device for recovering a feedstock liquid recovers the feedstock liquid remaining in the nozzles and mixes it with a fresh feedstock liquid.Type: GrantFiled: October 15, 2004Date of Patent: October 12, 2010Assignee: Nuclear Fuel Industries, Ltd.Inventors: Kazutoshi Okubo, Masashi Takahashi, Tomoo Takayama, Kazuhisa Nishimura, Masaki Honda
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Publication number: 20100219385Abstract: Fusion fuel container and reactant spin-enhancement for optimized fusion probability is disclosed. The enclosed nuclei in a cage-like molecule can include, for example, deuterium and tritium, and the cage-like molecule may be, for example, a fullerene molecule. A fusion reaction to consume the fusion fuel may be ignited, for example, via compression methods including chemical or laser.Type: ApplicationFiled: September 22, 2009Publication date: September 2, 2010Inventor: Edward Donald Miller
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Publication number: 20100123107Abstract: A nuclear fuel composition includes a transuranic fuel and a neutron moderator mixed with transuranic fuel. The neutron moderator includes at least one of hafnium or zirconium.Type: ApplicationFiled: November 20, 2008Publication date: May 20, 2010Inventor: Gregory A. Johnson
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Patent number: 7521007Abstract: Microstructured nuclear fuel adapted for nuclear power system use includes fissile material structures of micrometer-scale dimension dispersed in a matrix material. In one method of production, fissile material particles are processed in a chemical vapor deposition (CVD) fluidized-bed reactor including a gas inlet for providing controlled gas flow into a particle coating chamber, a lower bed hot zone region to contain powder, and an upper bed region to enable powder expansion. At least one pneumatic or electric vibrator is operationally coupled to the particle coating chamber for causing vibration of the particle coater to promote uniform powder coating within the particle coater during fuel processing. An exhaust associated with the particle coating chamber and can provide a port for placement and removal of particles and powder. During use of the fuel in a nuclear power reactor, fission products escape from the fissile material structures and come to rest in the matrix material.Type: GrantFiled: October 4, 2004Date of Patent: April 21, 2009Assignee: The United States of America as represented by the United States Department of EnergyInventors: Gordon D. Jarvinen, David W. Carroll, David J. Devlin
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Patent number: 6669874Abstract: A method for production of a nuclear fuel element with oxide base, in which the nuclear fuel with oxide base is mixed with Cr and sintered to a solid body. The amount of chrome oxide added is =>50 and <100 ppm with respect to the amount of nuclear fuel with oxide base added.Type: GrantFiled: February 21, 2002Date of Patent: December 30, 2003Assignee: Westinghouse Atom ABInventors: Philippe Abry, Sten Borell, Sven Eriksson
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Patent number: 6625248Abstract: A process for the treatment of radioactive graphite which includes the following steps: (i) reacting the radioactive graphite at a temperature in the range of from 250° C. to 900° C. with superheated steam or gases containing water vapor to form hydrogen and carbon monoxide; (ii) reacting the hydrogen and carbon monoxide from step (i) to form water and carbon dioxide; and (iii) reacting the carbon dioxide of step (ii) with metal oxides to for carbonate salts. The process enables radioactive graphite, such as graphite moderator, to be treated either in-situ or externally of a decommissioned nuclear reactor.Type: GrantFiled: October 1, 2001Date of Patent: September 23, 2003Assignee: Studsvik, Inc.Inventors: J. Bradley Mason, David Bradbury
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Patent number: 6235223Abstract: A sintered nuclear fuel body includes (U, Pu)O2 mixed crystals having a mean particle size in a range from 7.5 &mgr;m to 50 &mgr;m. This sintered nuclear fuel body has a high retention capacity for fission gas in a power reactor. In order to produce the sintered nuclear fuel body by sintering a body in a hydrogen-containing sintering atmosphere, a powered substance selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, chromium oxide, aluminum stearate, aluminum distearate and aluminum tristearate is added to the starting powder for the body. As an alternative or in addition, the body made from the starting powder is sintered during a holding period of 10 minutes to 8 hours at a sintering temperature of 1400° C. to 1800° C.Type: GrantFiled: November 4, 1998Date of Patent: May 22, 2001Assignee: Siemens AktiengesellschaftInventors: Wolfgang Doerr, Harald Cura, Gerhard Gradel
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Multicomponent fluid feed apparatus with preheater and mixer for a high temperature chemical reactor
Patent number: 5935528Abstract: A multicomponent fluid feed apparatus is disclosed that independently preheats and then mixes two or more fluid streams being introduced into a high temperature chemical reactor to promote more rigorous and complete reactions using assemblies of inert tubular elements and an integral mixing orifice plate. The design allows use of ceramic and speciality alloy materials for high temperature service with particularly corrosive halide feeds such as UF.sub.6 and HF. Radiant heat transfer to the tubular elements from external means gives the necessary system high temperatures without excessive temperatures to cause material failure. Preheating of the gaseous reactants in a separate step prior to mixing and injecting the gaseous reactants into a high temperature chemical reactor was found to provide an improved thermal conversion of UF.sub.6 to uranium oxides.Type: GrantFiled: January 14, 1997Date of Patent: August 10, 1999Assignee: Molten Metal Technology, Inc.Inventors: Michael J. Stephenson, Paul A. Haas, David A. Everitt -
Patent number: 5894501Abstract: A sintered nuclear fuel body includes (U, Pu)O.sub.2 mixed crystals having a mean particle size in a range from 7.5 .mu.m to 50 .mu.m. This sintered nuclear fuel body has a high retention capacity for fission gas in a power reactor. In order to produce the sintered nuclear fuel body by sintering a body in a hydrogen-containing sintering atmosphere, a powered substance selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, chromium oxide, aluminum stearate, aluminum distearate and aluminum tristearate is added to the starting powder for the body. As an alternative or in addition, the body made from the starting powder is sintered during a holding period of 10 minutes to 8 hours at a sintering temperature of 1400.degree. C. to 1800.degree. C. in a hydrogen-containing sintering atmosphere, initially with an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar and then from 10.sup.-8 to 10.sup.Type: GrantFiled: July 11, 1997Date of Patent: April 13, 1999Assignee: Siemens AktiengesellschaftInventors: Wolfgang Doerr, Harald Cura, Gerhard Gradel
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Patent number: 5753925Abstract: Horizontal partition wall 10 is disposed between ceiling slab 9 and floor slab 8. A plurality of storage tubes 6 each accomodating canister 2 are hanging from ceiling slab 9, and penetrate horizontal wall 10 to extend towards floor slab 8. Cooling passages are formed between horizontal partition wall 10 and ceiling slab 9 and between horizontal partition wall 10 and floor slab 8. Cooling air flowing through each of the cooling passages cools down storage tubes 6.Type: GrantFiled: June 26, 1995Date of Patent: May 19, 1998Assignee: Hitachi, Ltd.Inventors: Tsuneyasu Yamanaka, Masami Matsuda, Hidetoshi Kanai, Takao Ganda
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Patent number: 5585043Abstract: In a method of coextracting neptunium and plutonium, a nitric acid solution containing a mixture of neptunium and plutonium is oxidized by irradiation of ultraviolet light. As a result, different valences of neptunium are adjusted all into the valence 6, which can remain in water, and in the meantime, valences of plutonium are adjusted into the valence 4 or 6, which can be extracted in the organic phase. It is therefore possible to coextract neptunium and plutonium without difficulty. The coextracted neptunium and plutonium can be used in forming mixed fuel by blending at least a portion of at least one of neptunium and plutonium which neptunium and plutonium have been formed by separating a nitric acid solution containing neptunium and plutonium by exposing the solution and a reducing agent to ultraviolet radiation to adjust the valences, and extracting the solution using an organic phase to extract plutonium from the solution into the organic phase.Type: GrantFiled: September 12, 1994Date of Patent: December 17, 1996Assignee: Doryokuro Kakunenryo Kaihatsu JigyodanInventors: Yukio Wada, Kyoichi Morimoto, Takayuki Goibuchi, Hiroshi Tomiyasu
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Patent number: 5443702Abstract: Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of .sup.167 Er. The hyperfine structure of .sup.167 Er was used to find two three-step photoionization pathways having a common upper energy level.Type: GrantFiled: June 22, 1993Date of Patent: August 22, 1995Inventors: Christopher A. Haynam, Earl F. Worden
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Patent number: 5350542Abstract: By using AVLIS or other methods capable of providing a depleted isotopic mixture, troublesome isotopes such as Gd.sup.154, Gd.sup.156 and Er.sup.166 are selectively removed from naturally occurring isotopic mixtures, while avoiding the additional costs associated with complete fractionation of the mixture. Such mixtures can be used to provide a burnable nuclear fuel absorber having a selectively depleted isotope or isotopes. In particular, the invention concerns burnable absorbers containing erbium with a depleted 166 isotope, gadolinium with a depleted 156 isotope or with depleted 154 and 156 isotopes, and methods for making such absorbers.Type: GrantFiled: June 30, 1993Date of Patent: September 27, 1994Assignee: Combustion Engineering, Inc.Inventors: Leonard N. Grossman, Alf I. Jonsson
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Patent number: 5349618Abstract: A boiling water nuclear reactor used for the production of electricity includes fuel rods and an assembly of these fuel rods that improve the reactor economics and safety. The fuel assemblies include hydride fuel pellets at selected axial and radial positions in addition to oxide fuel pellets. The hydride fuel functions simultaneously as a fuel and as a moderator. The hydride fuel can be made from different combinations of fissionable materials such as uranium, and hydrides such as zirconium hydride. The hydride fuel (such as U-ZrH.sub.1.6) is substituted for oxide fuel (UO.sub.2) in undermoderated regions of the core. Hydride fuel rods also replace water rods in the fuel assemblies.Type: GrantFiled: September 9, 1992Date of Patent: September 20, 1994Inventor: Ehud Greenspan
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Patent number: 5250231Abstract: By using AVLIS or other methods capable of providing a depleted isotopic mixture, troublesome isotopes such as Gd.sup.154, Gd.sup.156 and Er.sup.166 are selectively removed from naturally occurring isotopic mixtures, while avoiding the additional costs associated with complete fractionation of the mixture. Such mixtures can be used to provide a burnable nuclear fuel absorber having a selectively depleted isotope or isotopes. In particular, the invention concerns burnable absorbers containing erbium with a depleted 166 isotope, gadolinium with a depleted 156 isotope or with depleted 154 and 156 isotopes, and methods for making such absorbers.Type: GrantFiled: September 18, 1991Date of Patent: October 5, 1993Assignee: Combustion Engineering, Inc.Inventors: Leonard N. Grossman, Alf I. Jonsson
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Patent number: 5188130Abstract: A chemical heat source comprising metal nitride, metal oxide and carbon, particularly useful in smoking articles, and methods of making the heat source are provided. The metal nitride of the heat source has an ignition temperature substantially lower than conventional carbonaceous heat sources, while at the same time provides sufficient heat to release a flavored aerosol from a flavor bed for inhalation by the smoker. Upon combustion the heat source produces virtually no carbon monoxide. The metal nitride is prepared by pre-forming the starting materials into a desired shape, and converting them to metal nitride in situ, without substantially altering the shape of the starting materials.Type: GrantFiled: November 29, 1989Date of Patent: February 23, 1993Assignee: Philip Morris, IncorporatedInventors: Mohammad R. Hajaligol, Seetharama C. Deevi, Sarojini D. Ariprala, Donald B. Losee, Bruce E. Waymack, Michael L. Watkins
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Patent number: 5015422Abstract: Making uranium dioxide pellets of controlled grain size by treating 50-500 g/l UO.sub.2 F.sub.2 with NH.sub.3 in a first and a second stages to form (NH.sub.4).sub.2 U.sub.2 O.sub.7 precipitate, wherein the NH.sub.3 /U molar ratio is between 3-5 in the first stage and between 6-12 in the second stage. The precipitate is then formed into UO.sub.2 pellets having grain size within the range from 10 to 100 .mu.m.Type: GrantFiled: January 13, 1989Date of Patent: May 14, 1991Assignee: Mitsubishi Kinzoku Kabushiki KaishaInventors: Tadao Yato, Takeshi Onoue, Hiroshi Tanaka
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Patent number: 4963294Abstract: A method of fabricating uranium dioxide (UO.sub.2) powder from uranium hexafluoride (UF.sub.6) is disclosed, which comprises(1) reacting UF.sub.6 gas with steam with controlling the temperature of reaction between said UF.sub.6 gas and said steam at a predetermined temperature within the range of 200.degree. to 700.degree. C., to form solid uranyl fluoride (UO.sub.2 F.sub.2) and/or uranium oxide with an O/U ratio (oxygen-to-uranium atomic ratio) of 2.7 to 3,(2) dissolving said UO.sub.2 F.sub.2 and/or uranium oxide in water or nitric acid to form an aqueous uranyl solution containing UO.sub.2 F.sub.2 and/or uranyl nitrate (UO.sub.2 (NO.sub.3).sub.2),(3) reacting said aqueous uranyl solution with ammonia to precipitate ammonium diuranate (ADU),(4) filtering said precipitate,(5) drying said precipitate,(6) calcining said dry precipitate, and(7) reducing said calcined precipitate, whereby controlling the characteristics of said UO.sub.2 powder.Type: GrantFiled: December 30, 1987Date of Patent: October 16, 1990Assignee: Mitsubishi Kinzoku Kabushiki KaishaInventors: Tadao Yato, Hiroshi Tanaka, Toshiaki Kikuchi, Toshio Onoshita
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Patent number: 4885147Abstract: A process for producing large-grain, low-density UO.sub.2 micro-fuel spheres, the micro-fuel spheres having an average grain diameter of at least 5 .mu.m, which comprises:(a) isothermally heating one or more UO.sub.2 micro-fuel spheres in a stream consisting essentially of carbon dioxide for a time and at a temperature sufficient to produce grains having an increased average grain diameter of greater than 5 .mu.m, without substantially increasing the density of said micro-fuel spheres; and then(b) sintering said produced grains, in the absence of a sintering additive, in a reducing gas stream for a time and at a temperature sufficient to regulate both the ratio of oxygen to uranium in the produced grains, and the density of the grains.Type: GrantFiled: November 14, 1988Date of Patent: December 5, 1989Assignee: Japan Atomic Energy Research InstituteInventors: Hirohiko Murakami, Toru Ogawa, Kousaku Fukuda
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Patent number: 4882100Abstract: A process of fabricating UO.sub.2 pellets comprising the steps of filtering and drying a slurry of ammonium diuranate (ADU) including ammonium fluoride (NH.sub.4 F), in order to form ADU powder, and then subjecting the ADU powder to calcining, reducing, compacting and sintering treatments, to form UO.sub.2 pellets.Type: GrantFiled: January 13, 1989Date of Patent: November 21, 1989Assignee: Mitsubishi Kinzoku Kabushiki KaishaInventors: Tadao Yato, Takeshi Onoue, Hiroshi Tanaka
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Patent number: 4873031Abstract: A method of controlling the crystal grain size of UO.sub.2 pellets is disclosed, which comprises(1) providing an aqueous uranyl solution which is free of hydrofluoric acid and nitric acid and which contains uranyl fluoride (UO.sub.2 F.sub.2) and/or uranyl nitrate (UO.sub.2 (NO.sub.3).sub.2) as a uranium component,(2) reacting with ammonia said aqueous uranyl solution to precipitate ammonium diuranate (ADU), while adjusting the ratio of said uranium components to a predetermined value within the range varying from the ratio 100% of uranyl fluoride and 0% of uranyl nitrate to the ratio 0% of uranyl fluoride and 100% of uranyl nitrate, adjusting the uranium concentration of the reaction mixture to 50 to 1,000 gU/liter and also adjusting the rate of contact between said uranium component in said aqueous uranyl solution with ammonia to at least 2 moles NH.sub.3 /min/mole U,(3) calcining and reducing said ADU precipitate to form UO.sub.2 powder, and(4) molding and sintering said UO.sub.2 powder, thus producing UO.Type: GrantFiled: December 30, 1987Date of Patent: October 10, 1989Assignee: Mitsubishi Kinzoku Kabushiki KaishaInventors: Tadao Yato, Sadaaki Hagino, Hiroshi Tanaka
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Patent number: 4871479Abstract: A process is disclosed for producing sintered mixed metal oxide nuclear f pellets containing UO.sub.2 and the oxide of at least one other fissionable or rare earth element M, the pellets being directly soluble in nitric acid without nitric acid additive or prior treatment of the pellets. The process comprises the steps of mixing together nitrate solutions of the elements, concentrating the mixture of solutions, thermally denitrating the concentrated nitrate mixture without additives, to obtain an intermediate mixed oxide powder, calcining the intermediate mixed oxide powder, reducing the calcined mixture, stabilizing the uranium oxide UO.sub.2 in the reduced oxide mixture, shaping and pressing the resulting stabilized, reduced oxide mixture to obtain pellets of green material, sintering the pellets of green material and grinding the sintered pellets.Type: GrantFiled: June 22, 1988Date of Patent: October 3, 1989Assignee: Comurhex Societe pour la Conversion de l'Uranium en Metal et HexafluorureInventors: Roland Bachelard, Patrick Germanaz
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Patent number: 4869866Abstract: A mixture of uranium dioxide and additive of aluminosilicate composition is formed into a compact and sintered to produce a nuclear fuel wherein the uranium dioxide grains have an average grain size of at least about 20 microns and wherein substantially all of the grains are each enveloped by glassy aluminosilicate phase.Type: GrantFiled: November 20, 1987Date of Patent: September 26, 1989Assignee: General Electric CompanyInventors: Kenneth W. Lay, Herman S. Rosenbaum, John H. Davies, Mickey O. Marlowe
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Patent number: 4869868Abstract: A particulate mixture of uranium dioxide and additive of magnesium silicate composition is formed into a compact and sintered to produce a nuclear fuel wherein the uranium dioxide grains have an average grain size of at least about 20 microns and wherein substantially all of the grains are each enveloped with glassy magnesium silicate phase.Type: GrantFiled: November 23, 1987Date of Patent: September 26, 1989Assignee: General Electric CompanyInventors: Kenneth W. Lay, Herman S. Rosenbaum, John H. Davies
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Patent number: 4869867Abstract: A particulate mixture of uranium dioxide and additive of magnesium aluminosilicate composition is formed into a compact and sintered to produce a nuclear fuel wherein the uranium dioxide grains have an average grain size of at least about 20 microns and wherein substantially all of the grains are each enveloped with glassy magnesium aluminosilicate phase.Type: GrantFiled: November 25, 1987Date of Patent: September 26, 1989Assignee: General Electric CompanyInventors: Kenneth W. Lay, Herman S. Rosenbaum, John H. Davies
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Patent number: 4816193Abstract: Method for manufacturing sintered oxidic nuclear fuel bodies by molding uranium oxide starting powder, a mixture of uranium oxide and plutonium oxide starting powder or of uranium-plutonium oxide mixed-crystal starting powder to form blanks and by a heat treatment of these blanks with a U.sub.4 O.sub.9 or (U, Pu).sub.4 O.sub.9 crystal phase developed in them to a degree which can be crystallographically detected at a sintering temperature in the range of 1000.degree. to 1400.degree. C. in an oxidizing and subsequently in a reducing gas atmosphere. The starting powder and/or the blanks are preroasted at a roasting temperature below the sintering temperature in a roasting gas atmosphere with oxidizing action and with an oxygen potential in which the U.sub.4 O.sub.9 (U, Pu).sub.4 O.sub.9 crystal phase is developed and cooled down subsequently to a starting temperature below the roasting temperature in an inert or oxidizing cooling-down gas atmosphere.Type: GrantFiled: September 18, 1987Date of Patent: March 28, 1989Assignees: Kraftwerk Union Aktiengesellschaft, Reaktor-Brennelement Union GmbHInventors: Martin Peehs, Heinrich Bayer, Ulrich Jenczio, Jurgen Laucht, Sieghard Hellmann, Gerhard Dichtjar, Wolfgang Dorr, Georg Maier
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Patent number: 4687605Abstract: An automated fuel rod production system includes a radioactive powder fabrication and processing stage, a pellet fabrication stage, a pellet processing stage, a tube preparation stage and a fuel rod fabrication and inspection stage, all of which provide a continuous (paced) mode of operation from the conversion of a radioactive gas to powder, through the fabrication of the powder into pellets, to completion of the assembly of the fuel rods. Extra capacity is designed into the system at critical points in the powder processing and pellet fabrication and processing stages to facilitate the continuous, paced mode of operation.Type: GrantFiled: February 19, 1985Date of Patent: August 18, 1987Assignee: Westinghouse Electric Corp.Inventors: Francis Cellier, Robert T. Graulty, Wendell L. Johnson, David M. Batson, John C. Limpert, Christopher K. C. Wu, George D. Bucher, Clarence D. John, Jr., John E. Steinkirchner, Paula J. Larouere, Hemant H. Shah, Robert A. Williams
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Patent number: 4671927Abstract: A nuclear fuel rod contains nuclear fuel pellets that have incorporated therein a hybrid burnable absorber that affects a moderation of the burn-out rate of the system containing the rod. The nuclear fuel pellets contain 1 to 20 percent by weight gadolinium oxide and 0.02 to 1.0 percent by weight of boron carbide particles of a size between 20 to 100 microns in diameter, the particles coated with a 0.5 to 10 micron thick coating of a helium gas-impervious coating.Type: GrantFiled: December 3, 1984Date of Patent: June 9, 1987Assignee: Westinghouse Electric Corp.Inventor: Brian H. Alsop
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Patent number: 4637900Abstract: A method is disclosed for making a fuel pellet for a nuclear reactor. A mixture is prepared of PuO.sub.2 and UO.sub.2 powders, where the mixture contains at least about 30% PuO.sub.2, and where at least about 12% of the Pu is the Pu.sup.240 isotope. To this mixture is added about 0.3 to about 5% of a binder having a melting point of at least about 250.degree. F. The mixture is pressed to form a slug and the slug is granulated. Up to about 4.7% of a lubricant having a melting point of at least about 330.degree. F. is added to the granulated slug. Both the binder and the lubricant are selected from a group consisting of polyvinyl carboxylate, polyvinyl alcohol, naturally occurring high molecular weight cellulosic polymers, chemically modified high molecular weight cellulosic polymers, and mixtures thereof. The mixture is pressed to form a pellet and the pellet is sintered.Type: GrantFiled: January 13, 1984Date of Patent: January 20, 1987Assignee: The United States of America as represented by the United States Department of EnergyInventor: James R. Frederickson
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Patent number: 4634571Abstract: For the production of plate-shaped fuel elements for research reactors having charges of more than 26 volume % of uranium compound in the aluminum matrix according to the known picture frame technique, 0.01 to 0.3 mm thick aluminum layers are applied by rolling to the picture before inserting it into the frame in order to avoid dragging the uranium into the fuel-free zones.Type: GrantFiled: March 5, 1985Date of Patent: January 6, 1987Assignee: NUKEM GmbHInventors: Horst Langhans, Erwin Wehner
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Patent number: 4493809Abstract: A nuclear fuel includes uranium dispersed within a thorium hydride matrix. The uranium may be in the form of particles including fissile and non-fissile isotopes. Various hydrogen to thorium ratios may be included in the matrix. The matrix with the fissile dispersion may be used as a complete fuel for a metal hydride reactor or may be combined with other fuels.Type: GrantFiled: March 8, 1982Date of Patent: January 15, 1985Assignee: GA Technologies Inc.Inventor: Massoud T. Simnad
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Patent number: 4367184Abstract: Nuclear fuel microspheres are made by sintering microspheres containing uranium dioxide and uncombined carbon in a 1 mole percent carbon monoxide/99 mole percent argon atmosphere at 1550.degree. C. and then sintering the microspheres in a 3 mole percent carbon monoxide/97 mole percent argon atmosphere at the same temperature.Type: GrantFiled: December 17, 1980Date of Patent: January 4, 1983Assignee: The United States of America as represented by the Department of EnergyInventor: David P. Stinton
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Patent number: 4366112Abstract: A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.Type: GrantFiled: June 22, 1976Date of Patent: December 28, 1982Assignee: The United States of America as represented by the United States Department of EnergyInventors: Robert J. Turnbull, Christopher A. Foster, Charles D. Hendricks