Patents by Inventor Takeshi Mitsuyasu
Takeshi Mitsuyasu 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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Publication number: 20230386687Abstract: A fuel assembly according to the present invention includes an end plug disposed on both upper and lower end portions of a fuel rod, and a tie plate that supports at least an upper portion of the end plug. The end plug includes a plurality of support protrusions on a surface of the end plug, and a closed-loop spring having a portion that is inserted through an opening portion formed in the end plug and is stored in a single space formed in the end plug, and a remaining portion protruding to the outside of the end plug. The end plug is supported by the plurality of support protrusions and the closed-loop spring in a state in which the plurality of support protrusions and the closed-loop spring are in contact with an inner wall of an insertion hole formed in the tie plate.Type: ApplicationFiled: April 26, 2023Publication date: November 30, 2023Inventors: Kiyoshi FUJIMOTO, Takuji NAGAYOSHI, Hajime FURUICHI, Takeshi MITSUYASU
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Patent number: 11728046Abstract: A fuel assembly includes full length fuel rods which contain a plutonium fissile (Puf) but do not contain a burnable poison, full length fuel rods which contain the fissile uranium and the burnable poison, and partial length fuel rods which contain Puf but do not contain the burnable poison in a channel box. The plutonium enrichment is decreased in an order of the full length fuel rods. The concentration of the burnable poison of the full length fuel rod is higher than the concentration of the full length fuel rod. In each side of a rectangular outermost periphery adjacent to the inner surface of the channel box in a horizontal cross-sectional view of the fuel assembly, two partial length fuel rods are adjacently disposed, and the full length fuel rod containing the burnable poison is disposed to be adjacent to each partial length fuel rod.Type: GrantFiled: March 21, 2019Date of Patent: August 15, 2023Assignee: HITACHI-GE NUCLEAR ENERGY, LTD.Inventors: Takeshi Mitsuyasu, Motoo Aoyama
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Patent number: 10957457Abstract: A fuel assembly, which linearizes change of an infinite multiplication factor of a fuel and flattens excess reactivity while increasing average fissile plutonium enrichment of a MOX fuel, and a reactor are provided. The fuel assembly includes first fuel rods containing Pu and not containing burnable poison, a second fuel rod containing uranium and burnable poison and not containing Pu, a water rod, and a channel box accommodating the first and second fuel rods and the water rod in a bundle. The second fuel rod is disposed on an outermost periphery and/or adjacent to the water rod, of a fuel rod array in a horizontal section, and N2<N1 (N2 is a positive integer or zero) is satisfied where the number of second fuel rods arranged on the outermost periphery is N1 and the number of second fuel rods arranged adjacent to the water rod is N2.Type: GrantFiled: February 23, 2016Date of Patent: March 23, 2021Assignee: Hitachi, Ltd.Inventors: Takeshi Mitsuyasu, Motoo Aoyama
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Patent number: 10706978Abstract: There is provided a core of a boiling water reactor that can be operated without loading a new fuel assembly at an operation cycle before decommissioning. The core of the boiling water reactor includes multiple fuel assemblies loaded in a square lattice shape. The multiple fuel assemblies are arranged in the core based on the number of residence cycles of fuel assemblies laterally adjacent and longitudinally adjacent to a fuel assembly having the shortest loading period in core cross section. The arrangement of fuel assemblies is also based on the number of residence cycles of fuel assemblies diagonally adjacent to the fuel assembly having the shortest loading period.Type: GrantFiled: October 18, 2017Date of Patent: July 7, 2020Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Michitaka Ono, Motoo Aoyama, Takeshi Mitsuyasu
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Publication number: 20200194132Abstract: When all fuel assemblies loaded in a region excluding an outermost periphery of the reactor core in an Nth operation cycle belong to the first fuel assembly, and all fuel assemblies loaded in the region excluding the outermost periphery of the reactor core in a (N+m) th (m>1) operation cycle belong to the second fuel assembly, the number of new loaded second fuel assemblies in the (N+m) th operation cycle is greater than the number of new loaded second fuel assemblies in a (N+m?1) th operation cycle which is one operation cycle before the (N+m) th operation cycle, and a cycle burnup in the (N+m) th operation cycle is greater than a cycle burnup in the (N+m?1) th operation cycle.Type: ApplicationFiled: November 21, 2019Publication date: June 18, 2020Inventor: Takeshi MITSUYASU
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Publication number: 20200027584Abstract: A fuel assembly includes full length fuel rods which contain a plutonium fissile (Puf) but do not contain a burnable poison, full length fuel rods which contain the fissile uranium and the burnable poison, and partial length fuel rods which contain Puf but do not contain the burnable poison in a channel box. The plutonium enrichment is decreased in an order of the full length fuel rods. The concentration of the burnable poison of the full length fuel rod is higher than the concentration of the full length fuel rod. In each side of a rectangular outermost periphery adjacent to the inner surface of the channel box in a horizontal cross-sectional view of the fuel assembly, two partial length fuel rods are adjacently disposed, and the full length fuel rod containing the burnable poison is disposed to be adjacent to each partial length fuel rod.Type: ApplicationFiled: March 21, 2019Publication date: January 23, 2020Inventors: Takeshi MITSUYASU, Motoo AOYAMA
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Publication number: 20190051421Abstract: A fuel assembly capable of linearizing change of an infinite multiplication factor of a fuel and flattening excess reactivity while increasing average fissile plutonium enrichment of a MOX fuel, and a reactor loaded with the fuel assembly can be provided. A fuel assembly includes first fuel rods containing Pu and not containing burnable poison, a second fuel rod containing uranium and burnable poison and not containing Pu, a water rod, and a channel box accommodating the first and second fuel rods and the water rod in a bundle.Type: ApplicationFiled: February 23, 2016Publication date: February 14, 2019Inventors: Takeshi MITSUYASU, Motoo AOYAMA
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Publication number: 20180122522Abstract: There is provided a core of a boiling water reactor that can be operated without loading a new fuel assembly at an operation cycle before decommissioning. In the core of the boiling water reactor in which multiple fuel assemblies are loaded in a square lattice shape, during the fuel exchange, dispositions of the multiple fuel assemblies loaded into the core are changed without loading a new fuel assembly in the core, based on the number of residence cycles, in the core, of fuel assemblies laterally adjacent and longitudinally adjacent to a fuel assembly having the shortest loading period in core cross section and the number of residence cycles, in the core, of fuel assemblies diagonally adjacent thereto, among fuel assemblies loaded into the core after the fuel exchange without loading a fuel assembly having a shorter loading period than a fuel assembly having the shortest loading period loaded into the core before the fuel exchange in the core after the fuel exchange.Type: ApplicationFiled: October 18, 2017Publication date: May 3, 2018Inventors: Michitaka ONO, Motoo AOYAMA, Takeshi MITSUYASU
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Patent number: 9646724Abstract: In a fuel assembly, a plurality of fuel rods are arranged in an array of 10 rows and 10 columns in the cross section of the fuel assembly. A flow resistance member is disposed in a central portion in the cross section at upper end portions of partial length fuel rods which are a part of the fuel rods. In the flow resistance member, resistance members are each disposed between ferrules arranged in an array of 6 rows and 6 columns in the diagonal direction of the flow resistance member. Resistance members are each disposed between the ferrules in a peripheral portion of the flow resistance member. By disposing the resistance members, the pressure loss in an inner region in the cross section of the fuel assembly is increased, and the flow rate of a gas-liquid two-phase flow in an outer region surrounding the inner region is increased.Type: GrantFiled: December 18, 2013Date of Patent: May 9, 2017Assignee: Hitachi, Ltd.Inventors: Takeshi Mitsuyasu, Motoo Aoyama, Takuji Nagayoshi, Kenichi Katono
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Publication number: 20160260506Abstract: The initial-core economical efficiency is improved by loading the medium enriched fuel in the peripheral or lacing it adjacent to the low enriched fuel and the highly enriched fuel. According to the present invention, in an initial core of a Boiling Water Reactor loaded with at least three types of fuel including highly enriched fuel with a fission-material content of 3.0 wt % or more, medium enriched fuel with a fission-material content of a range from 1.5 wt % or more to less than 3.0 wt %, and low enriched fuel with a fission-material content of less than 1.Type: ApplicationFiled: October 21, 2013Publication date: September 8, 2016Inventors: Takeshi MITSUYASU, Motoo AOYAMA
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Publication number: 20140185735Abstract: In a fuel assembly, a plurality of fuel rods are arranged in an array of 10 rows and 10 columns in the cross section of the fuel assembly. A flow resistance member is disposed in a central portion in the cross section at upper end portions of partial length fuel rods which are a part of the fuel rods. In the flow resistance member, resistance members are each disposed between ferrules arranged in an array of 6 rows and 6 columns in the diagonal direction of the flow resistance member. Resistance members are each disposed between the ferrules in a peripheral portion of the flow resistance member. By disposing the resistance members, the pressure loss in an inner region in the cross section of the fuel assembly is increased, and the flow rate of a gas-liquid two-phase flow in an outer region surrounding the inner region is increased.Type: ApplicationFiled: December 18, 2013Publication date: July 3, 2014Applicant: Hitachi, Ltd.Inventors: Takeshi MITSUYASU, Motoo AOYAMA, Takuji NAGAYOSHI, Kenichi KATONO
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Publication number: 20140064433Abstract: In a fuel assembly having fuel rods U1 to U4, and P1 not containing gadolinia, and fuel rods G1-G3 containing gadolinia, the concentrations a of gadolinia in nuclear fuel materials A (8 wt % and 10 wt %) satisfy 0.7<a/amax?1.0, the concentrations b of gadolinia in nuclear fuel materials B (5 wt % and 6 wt %) satisfy 0.4<b/amax?0.7, the concentration c of gadolinia in a nuclear fuel material C (2 wt %) satisfies 0<c/amax?0.4, and L(A)/5.0?L(B) and L(B)/5.0?L(C) are satisfied. The gadolinia with concentrations a burns out during the end of cycle, the gadolinia with concentrations b during the middle of cycle, and the gadolinia with a concentration c during the beginning of cycle. L(A) is the total axial length of zones filled with the nuclear fuel materials A in the fuel rods G1-G3, L(B) for materials B in G2 and G3, and L(C) material C in G1.Type: ApplicationFiled: August 29, 2013Publication date: March 6, 2014Applicant: Hitachi-GE Nuclear Energy, Ltd.Inventors: Naoyuki Nakadozono, Takeshi Mitsuyasu, Tomohiko Ikegawa
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Publication number: 20140037039Abstract: A fuel assembly with a plurality of fuel rods, extending along a uniform direction, disposed inside a channel box assuming a quadrangular duct shape, wherein: the plurality of fuel rods that are disposed on sides of a plurality of hypothetical concentric quadrangles of various sizes with shapes similar to a cross-sectional shape of the channel box viewed from an end along which the fuel rods extend, and include at least outermost fuel rods disposed on the sides of a largest hypothetical concentric quadrangle among the hypothetical concentric quadrangles and second layer fuel rods disposed on the sides of a second largest hypothetical concentric quadrangle among the hypothetical concentric quadrangles; and the outermost fuel rods are disposed so that consecutive outermost fuel rods are set apart from each other over equal intervals which are greater than intervals setting apart consecutive fuel rods among the second layer fuel rods.Type: ApplicationFiled: July 31, 2013Publication date: February 6, 2014Applicant: Hitachi-GE Nuclear Energy, Ltd.Inventors: Takeshi MITSUYASU, Motoo AOYAMA, Takuji NAGAYOSHI, Kenichi KATONO
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Publication number: 20130051509Abstract: In an initial core of a nuclear reactor, a plurality of water regions having a square cross section for occupying a cross sectional area capable of disposing four fuel assemblies are formed. No fuel assemblies are loaded in these water regions. In the initial core, each fuel assembly is supported by fuel supports. A pressure loss of a first orifice installed in a cooling water supply passage formed in first fuel supports disposed in a central portion of the initial core is larger than that of a second orifice installed in a cooling water supply passage formed in second fuel supports disposed in a peripheral portion surrounding the central portion. Each water region is formed right above a part of the first fuel supports disposed in the central portion. The control rod operation in the nuclear reactor can be simplified by action of cooling water in the water regions.Type: ApplicationFiled: August 24, 2012Publication date: February 28, 2013Applicant: Hitachi-GE Nuclear Energy, Ltd.Inventors: Takeshi Mitsuyasu, Motoo Aoyama, Naoyuki Nakadozono, Kazuya Ishii
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Patent number: 8311180Abstract: A fuel assembly, comprising: a plurality of first fuel rods including uranium and not including a burnable poison; a plurality of second fuel rods including said uranium and said burnable poison; and a water rod; wherein said second fuel rods are placed at corners of an outermost layer of a fuel rod array; other second fuel rods are placed, in said outermost layer, adjacent to said second fuel rods placed at said corners; and other second fuel rods are placed adjacent to said water rod.Type: GrantFiled: December 11, 2008Date of Patent: November 13, 2012Assignee: Hitachi, Ltd.Inventors: Takeshi Mitsuyasu, Motoo Aoyama, Tetsushi Hino
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Publication number: 20120063561Abstract: A fuel assembly has a constitution in which plural fuel rods are arranged in 10 rows by 10 columns in a channel box, and includes plural fuel rods G containing gadolinium and plural partial length fuel rods P. In the fuel assembly, average enrichment of lower portion cross section is approximately 4.6 wt %, and average enrichment of upper portion cross section is approximately 4.7 wt %. The average enrichments at the outermost layer are approximately 5.6 wt % both in the upper portion and the lower portion. Ratios e/x of the average enrichment of the outermost layer e (wt %) to the average enrichment of the fuel assembly cross section x (wt %) are 1.19 in the upper portion and 1.22 in the lower portion, and the ratios satisfy equation (1). [ Equation ? ? 1 ] ? e x ? - 18.3 ? ( x 10 ) 5 + 68.766 ? ( x 10 ) 4 - 101.77 ? ( x 10 ) 3 + 74.428 ? ( x 10 ) 2 - 27.372 ? ( x 10 ) + 5.Type: ApplicationFiled: August 31, 2011Publication date: March 15, 2012Inventors: Takeshi MITSUYASU, Motoo AOYAMA, Tetsushi HINO, Takuji NAGAYOSHI, Masao CHAKI
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Patent number: 8064565Abstract: A reactor core, comprising: an outermost region; a core region surrounded by said outermost region; a plurality of fuel support members, each of which is disposed at a lower end portion of said outermost region and said core region; and a plurality of fuel assemblies loaded in said outermost region and said core region and supported by said fuel support members, wherein a plurality of fuel assemblies disposed in said core region include a plurality of first fuel assemblies, each of which is inserted into a first coolant passage which is formed in said fuel support member and has a first resistor having an opening, and a plurality of second fuel assemblies, each of which is individually inserted into each of second coolant passage which is formed in said fuel support member and has a second resistor having an opening and a larger pressure loss than that of said first resistor; and, four fuel assemblies, each of which is adjacent to each of four lateral sides of each of a plurality of first fuel assemblies,Type: GrantFiled: November 24, 2009Date of Patent: November 22, 2011Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Takeshi Mitsuyasu, Motoo Aoyama, Kazuya Ishii, Masao Chaki
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Publication number: 20100128833Abstract: A reactor core, comprising: an outermost region; a core region surrounded by said outermost region; a plurality of fuel support members, each of which is disposed at a lower end portion of said outermost region and said core region; and a plurality of fuel assemblies loaded in said outermost region and said core region and supported by said fuel support members, wherein a plurality of fuel assemblies disposed in said core region include a plurality of first fuel assemblies, each of which is inserted into a first coolant passage which is formed in said fuel support member and has a first resistor having an opening, and a plurality of second fuel assemblies, each of which is individually inserted into each of second coolant passage which is formed in said fuel support member and has a second resistor having an opening and a larger pressure loss than that of said first resistor; and, four fuel assemblies, each of which is adjacent to each of four lateral sides of each of a plurality of first fuel assemblies,Type: ApplicationFiled: November 24, 2009Publication date: May 27, 2010Inventors: Takeshi Mitsuyasu, Motoo Aoyama, Kazuya Ishii, Masao Chaki
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Publication number: 20090252282Abstract: A fuel assembly, comprising: a plurality of first fuel rods including uranium and not including a burnable poison; a plurality of second fuel rods including said uranium and said burnable poison; and a water rod; wherein said second fuel rods are placed at corners of an outermost layer of a fuel rod array; other second fuel rods are placed, in said outermost layer, adjacent to said second fuel rods placed at said corners; and other second fuel rods are placed adjacent to said water rod.Type: ApplicationFiled: December 11, 2008Publication date: October 8, 2009Inventors: Takeshi MITSUYASU, Motoo Aoyama, Tetsushi Hino
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Publication number: 20090196392Abstract: A core of a boiling water reactor as a burner type core of the boiling water reactor having a ratio of 3 or more of number of fuel assemblies loaded in the core to number of control rods installed in the nuclear reactor and using an oxide of low enriched uranium having a mean enrichment of the fuel assemblies of 3 wt % to 8 wt % or a mixed oxide having a mean fissile plutonium enrichment of the fuel assemblies of 2 wt % to less than 7 wt %, wherein a ratio of an inner width of a channel box of the fuel assemblies to a width of 0.79 to 0.865, and a mean thickness of the channel box of the fuel assemblies is 2.10 to 3.55 mm.Type: ApplicationFiled: April 11, 2008Publication date: August 6, 2009Inventors: Junichi MIWA, Renzo Takeda, Takeshi Mitsuyasu, Kumiaki Moriya