Patents by Inventor Gerhard Gradel
Gerhard Gradel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6808656Abstract: A nuclear fuel sintered body is produced from a powder which contains at least one fissile heavy metal oxide. During the further treatment of the powder over the course of the process preceding the sintering operation, a dopant that contains at least 100 ppm of an iron oxide compound is added to the powder. The powder is a UO2-containing powder obtained from a dry-chemical conversion process, and if appropriate, a powder which contains further fissile heavy metal oxide (U3O8, PuO2, inter alia). As a result, the sintered body is provided with high plasticity combined, at the same time, with a large grain size. This advantageously reduces an interaction between the nuclear fuel sintered body and a fuel rod cladding tube during an operation of the reactor.Type: GrantFiled: March 27, 2002Date of Patent: October 26, 2004Assignee: Framatome ANP GmbHInventors: Gerhard Gradel, Wolfgang Dörr
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Patent number: 6617558Abstract: A furnace is provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.Type: GrantFiled: June 26, 2002Date of Patent: September 9, 2003Assignee: Framatome ANP GmbHInventors: Wolfgang Dörr, Thorsten Gerdes, Gerhard Gradel, Bruno Schmitt, Monika Willert-Porada
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Publication number: 20020158066Abstract: A furnace is provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.Type: ApplicationFiled: June 26, 2002Publication date: October 31, 2002Applicant: Siemens AktiengesellschaftInventors: Wolfgang Dorr, Thorsten Gerdes, Gerhard Gradel, Bruno Schmitt, Monika Willert-Porada
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Publication number: 20020149125Abstract: A nuclear fuel sintered body is produced from a powder which contains at least one fissile heavy metal oxide. During the further treatment of the powder over the course of the process preceding the sintering operation, a dopant that contains at least 100 ppm of an iron oxide compound is added to the powder. The powder is a UO2-containing powder obtained from a dry-chemical conversion process, and if appropriate, a powder which contains further fissile heavy metal oxide (U3O8, PuO2, inter alia). As a result, the sintered body is provided with high plasticity combined, at the same time, with a large grain size. This advantageously reduces an interaction between the nuclear fuel sintered body and a fuel rod cladding tube during an operation of the reactor.Type: ApplicationFiled: March 27, 2002Publication date: October 17, 2002Inventors: Gerhard Gradel, Wolfgang Dorr
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Patent number: 6437303Abstract: A method and a furnace are provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.Type: GrantFiled: August 21, 2000Date of Patent: August 20, 2002Assignee: Siemens AktiengesellschaftInventors: Wolfgang Dörr, Thorsten Gerdes, Gerhard Gradel, Bruno Schmitt, Monika Willert-Porada
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Publication number: 20010022827Abstract: A nuclear reactor fuel assembly with a high burnup is provided. In order to increase the burnup potential of fuel assemblies, pellets with an impermissibly high level of enrichment are produced on production lines, which are constructed for processing large quantities of normally enriched fuel. The impermissible level of enrichment is compensated for by the fact that, as early as in a powder mixer at an entry to the production line, so much absorber material is mixed with the fuel that the reactivity of the poisoned mixture does not exceed the reactivity of an unpoisoned fuel mixture with a normal level of enrichment. Corresponding fuel assemblies then contain relatively large quantities of these poisoned pellets (or only such poisioned pellets), which can be produced in large numbers (and therefore economically) by using conventional plants.Type: ApplicationFiled: May 23, 2001Publication date: September 20, 2001Applicant: Siemens AktiengesellschaftInventors: Gerhard Gradel, Alfons Roppelt, Rudolf Meinl
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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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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: 5642390Abstract: A uranium-containing nuclear-fuel sintered pellet containing UO.sub.2, (U, Pu)O.sub.2, (U, Th)O.sub.2, (U, RE)O.sub.2, (U, Pu, Th)O.sub.2, (U, Pu, RE)O.sub.2, (U, Th, RE)O.sub.2 or (U, Pu, Th, RE)O.sub.2, wherein RE=rare earth, has a sintered-pellet surface layer being formed of at least 80% by volume of a chemical boron compound UB.sub.x or (U, . . . )B.sub.x, wherein x=2;4;6 or 12, and a remainder of the sintered pellet containing at most 5% by volume of the chemical boron compound. A nuclear-reactor fuel assembly has a fuel rod containing such a uranium-containing nuclear-fuel sintered pellet in a cladding tube with the boron as a burnable absorber for thermal neutrons. The surface layer having the chemical boron compound is obtained by treating the nuclear-fuel sintered pellet with boron or a boron-containing chemical compound at an appropriately high treatment temperature.Type: GrantFiled: February 9, 1996Date of Patent: June 24, 1997Assignee: Siemens AktiengesellschaftInventors: Harald Cura, Martin Peehs, Gerhard Gradel, Alfons Roppelt, Erhard Ortlieb, Richard A. Perkins
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Patent number: 4671904Abstract: UO.sub.2 base powder exhibiting any specific surface and crystallite diameter properties is mixed with rare earth (SE) oxide-containing powder, the particles of which exhibit at least in one surface layer, a crystal lattice of the fluorite type, with the stoichiometric composition (SE.sub.0.5, U.sub.0.5) 0.sub.2.00 and/or form it in sintering; and is compacted to form compacts which are sintered in a gas atmosphere with reducing action at 1500.degree. C. to 1750.degree. C. to form high-density sintered bodies.Type: GrantFiled: February 14, 1985Date of Patent: June 9, 1987Assignee: Kraftwerk Union AktiengesellschaftInventors: Wolfgang Dorr, Gerhard Gradel, Martin Peehs
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Patent number: 4663112Abstract: Method for determining the contents of a fuel rod within a testing range extending in the longitudinal direction of the fuel rod, characterized by the features that(a) the position of a test coil concentrically surrounding the fuel rod is changed from the beginning to the end of the testing range, and(b) in the process, the impedance of the test coil is measured as a function of its position,(c) the test coil is fed with an a-c voltage,(d) the frequency of which is so low that the measurement value in the region of a fuel pellet of pure uranium dioxide is clearly distinguished from that which is measured in the region of a doped fuel pellet.Type: GrantFiled: March 14, 1984Date of Patent: May 5, 1987Assignee: Kraftwerk Union AktiengesellschaftInventors: Gerhard Gradel, Peter Wahode, Wolfgang Dorr
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Patent number: 4512939Abstract: Method for the manufacture of oxidic sintered nuclear fuel bodies by compacting UO.sub.2 -starting powder or a mixture of UO.sub.2 -and PuO.sub.2 starting powder which contains up to 10% by weight rare-earth oxide, especially Gd.sub.2 O.sub.3, as an additive into blanks and subsequent densification of these blanks by a heat treatment in a sintering atomsphere with reducing action. The UO.sub.2 -starting powder used for compacting has a specific surface in the range of 2 to 4.5 m.sup.2 /g and/or a mean crystallite diameter in the range of 80 nm to 250 nm, and the heat treatment in the sintering atmosphere with reducing action is carried out at a temperature in the range of 1,500.degree. C. to 1,750.degree. C.Type: GrantFiled: September 30, 1982Date of Patent: April 23, 1985Assignees: Kraftwerk Union Aktiengesellschaft, Reaktor Brennelement Union GmbHInventors: Wolfgang Dorr, Gerhard Gradel, Martin Peehs, Reinhard Schafer, Thomas Sondermann
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Patent number: 4438050Abstract: Manufacture of very dense oxidic fuel bodies of UO.sub.2 with rare earth oxides in which pressed blanks are subjected to sintering in an oxidizing atmosphere at relatively low temperature and are sintered in a reducing atmosphere at a higher temperature. This avoids sintering-inhibiting phases and permits very dense bodies with greater content of rare earth oxides to be produced.Type: GrantFiled: September 26, 1980Date of Patent: March 20, 1984Assignee: Kraftwerk Union AktiengesellschaftInventors: Wolfgang Dorr, Gerhard Gradel, Martin Peehs