Patents by Inventor Masao Chaki
Masao Chaki 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: 10726959Abstract: When a power source is lost after an operation stop of a nuclear power plant, a first open/close valve is opened via a first battery at an early stage and steam in a reactor pressure vessel (RPV) is condensed in a suppression pool. The heat of the water in the suppression pool is transmitted to a cooling water pool located below inner space between first and second reactor containment vessels surrounding the RPV. A second open/close valve is opened via a second battery at the early stage and cooling water in a tank is injected into the RPV. After the early stage, a third open/close valve is opened via a third battery, and a cooling medium becomes steam by an evaporator in the RPV, the steam being condensed by a condenser disposed in the inner space to become a liquid of the cooling medium and is returned to the evaporator.Type: GrantFiled: April 14, 2016Date of Patent: July 28, 2020Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Kenichi Katono, Masao Chaki, Kazuaki Kito
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Publication number: 20160293281Abstract: When a power source is lost after an operation stop of a nuclear power plant, a first open/close valve is opened via a first battery at an early stage and steam in a reactor pressure vessel (RPV) is condensed in a suppression pool. The heat of the water in the suppression pool is transmitted to a cooling water pool located below inner space between first and second reactor containment vessels surrounding the RPV. A second open/close valve is opened via a second battery at the early stage and cooling water in a tank is injected into the RPV. After the early stage, a third open/close valve is opened via a third battery, and a cooling medium becomes steam by an evaporator in the RPV, the steam being condensed by a condenser disposed in the inner space to become a liquid of the cooling medium and is returned to the evaporator.Type: ApplicationFiled: April 14, 2016Publication date: October 6, 2016Inventors: Kenichi KATONO, Masao CHAKI, Kazuaki KITO
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Patent number: 8453451Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: GrantFiled: March 11, 2011Date of Patent: June 4, 2013Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Masao Chaki, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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Patent number: 8291704Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: GrantFiled: March 11, 2011Date of Patent: October 23, 2012Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Masao Chaki, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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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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Patent number: 7997078Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: GrantFiled: October 6, 2009Date of Patent: August 16, 2011Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Masao Chaki, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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Publication number: 20110162363Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: ApplicationFiled: March 11, 2011Publication date: July 7, 2011Inventors: Masao CHAKI, Kazuaki KITOU, Motoo AOYAMA, Masaya OOTSUKA, Kouji SHIINA
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Publication number: 20110162364Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: ApplicationFiled: March 11, 2011Publication date: July 7, 2011Inventors: Masao Chaki, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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Patent number: 7970094Abstract: A nuclear power plant and method of operation for augmenting a second reactor thermal power output in a second operation cycle to a level larger than a first reactor thermal power output in the previous operation cycle. The plant is equipped, for example, with a reactor; a steam loop comprising high and low pressure turbines; a condenser for condensing steam discharged therefrom the low pressure turbine; a feedwater heater for heating feedwater supplied from the condenser; and a feedwater loop for leading feedwater discharged from the feedwater heater to the reactor. The operation method includes decreasing a ratio of extraction steam which is led to the feedwater heater from a steam loop in the second operation cycle.Type: GrantFiled: January 2, 2008Date of Patent: June 28, 2011Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Kazuaki Kitou, Masao Chaki, Kouji Shiina, Motoo Aoyama, Masaya Ohtsuka, Masayuki Nagasawa, Minoru Okura, Seiji Nemoto, Yasuhiro Takahashi
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Patent number: 7835483Abstract: A steam separator comprises an outer main swirler and an inner auxiliary swirler which is smaller than the main swirler. The swirlers are provided so as to be concentric on the inner wall at the lower side of the first stage inner cylinder. In the steam separator, when the gas-liquid two-phase flow which flows in the vicinity of the axial center of the first stage inner cylinder passes the auxiliary swirler, it is separated into steam and water by the centrifugal force. The separated water (droplets) is introduced into the main swirler. When the separated water (droplets) passes the main swirler, it is separated at the inner wall side of the first stage inner cylinder by the centrifugal force. Pressure loss in a steam separator is reduced and steam separation capability is increased without increasing the moisture from the steam separator.Type: GrantFiled: February 28, 2007Date of Patent: November 16, 2010Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Masao Chaki, Michio Murase, Naoyuki Ishida
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Publication number: 20100170246Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: ApplicationFiled: October 6, 2009Publication date: July 8, 2010Inventors: Masao CHAKI, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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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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Patent number: 7614233Abstract: In a nuclear power plant, thermal power in a second operation cycle of a nuclear reactor is uprated from thermal power in a first operation cycle preceding the second operation cycle by at least one operation cycle. A proportion of steam extracted from a steam system and introduced to a feedwater heater, which is in particular extracted from an intermediate point and an outlet of a high pressure turbine, with respect to a flow rate of main steam, is reduced in the second operation cycle from that in the first operation cycle such that the temperature of feedwater discharged from the feedwater heater is lowered by 1° C. to 40° C. in the second operation cycle.Type: GrantFiled: January 27, 2006Date of Patent: November 10, 2009Assignee: Hitachi-GE Nuclear Energy, Ltd.Inventors: Masao Chaki, Kazuaki Kitou, Motoo Aoyama, Masaya Ootsuka, Kouji Shiina
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Publication number: 20090141847Abstract: An method for operating a nuclear power generation plant, comprising the steps of: forming a plurality of control rod patterns by operating a plurality of control rods during a first period of one operation cycle of a reactor including said first period before a point of time when all control rods are completely withdrawn from a core of said reactor and a core flow rate reaches firstly a set core flow rate, and a second period after said point of time, controlling stepwise at least once a temperature of feed water supplied to said reactor based on a different set feed water temperature during a period included in said first period for operating said reactor with a formed same control rod pattern, and continuing feed water temperature control based on said set feed water temperature until said core flow rate reaches a set core flow rate set based on said set feed water temperature.Type: ApplicationFiled: November 28, 2008Publication date: June 4, 2009Inventors: Tetsushi HINO, Masao CHAKI, Motoo AOYAMA, Takeshi MITSUYASU, Yoshihiko ISHII
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Publication number: 20090041174Abstract: 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, incType: ApplicationFiled: August 6, 2008Publication date: February 12, 2009Inventors: Takeshi MITSUYASU, Motoo AOYAMA, Kazuya ISHII, Masao CHAKI
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Publication number: 20080317191Abstract: The present invention decreases the temperature of feed water supplied to the reactor of a set power when the flow rate of coolant supplied to the core of the reactor increases in the end of an operation cycle. This operating method can increase the thermal power of the nuclear power generation plant and increase the economical efficiency of fuel even when the operation cycle is prolonged. Particularly, even when the core flow rate increases in the end of the operation cycle, this method can suppress the rise of the cooling water temperature at the inlet of the core. Consequently, this invention can make the reactivity gain higher than that when the core flow rate is singly increased. The present invention can increase the thermal power of a nuclear reactor, and can improve the economical efficiency of fuel even when a period of an operation cycle is made longer.Type: ApplicationFiled: June 20, 2007Publication date: December 25, 2008Inventors: Masao Chaki, Motoo Aoyama, Tetsushi Hino, Kazuya Ishii
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Publication number: 20080181349Abstract: A nuclear power plant and method of operation for augmenting a second reactor thermal power output in a second operation cycle to a level larger than a first reactor thermal power output in the previous operation cycle. The plant is equipped, for example, with a reactor; a steam loop comprising high and low pressure turbines; a condenser for condensing steam discharged therefrom the low pressure turbine; a feedwater heater for heating feedwater supplied from the condenser; and a feedwater loop for leading feedwater discharged from the feedwater heater to the reactor. The operation method includes decreasing a ratio of extraction steam which is led to the feedwater heater from a steam loop in the second operation cycle.Type: ApplicationFiled: January 2, 2008Publication date: July 31, 2008Applicant: Hitachi, Ltd.Inventors: Kazuaki Kitou, Masao Chaki, Kouji Shiina, Motoo Aoyama, Masaya Ohtsuka, Masayuki Nagasawa, Minoru Okura, Seiji Nemoto, Yasuhiro Takahashi
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Patent number: 7333584Abstract: A nuclear power plant and method of operation for augmenting a second reactor thermal power output in a second operation cycle to a level larger than a first reactor thermal power output in the previous operation cycle. The plant is equipped, for example, with a reactor; a steam loop comprising high and low pressure turbines; a condenser for condensing steam discharged therefrom the low pressure turbine; a feedwater heater for heating feedwater supplied from the condenser; and a feedwater loop for leading feedwater discharged from the feedwater heater to the reactor. The operation method includes decreasing a ratio of extraction steam which is led to the feedwater heater from a steam loop in the second operation cycle.Type: GrantFiled: January 13, 2005Date of Patent: February 19, 2008Assignee: Hitachi - GE Nuclear Energy, Ltd.Inventors: Kazuaki Kitou, Masao Chaki, Kouji Shina, Motoo Aoyama, Masaya Ohtsuka, Masayuki Nagasawa, Minoru Okura, Seiji Nemoto, Yasuhiro Takahashi
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Publication number: 20070274428Abstract: The natural circulation type boiling water reactor comprises a core in which a plurality of fuel assemblies are loaded, and a chimney which is disposed above the core and has a path partition which forms a plurality of vertical lattice paths. A uniform pressure space is formed between the core and the chimney and not disposed the path partition. The two-phase flow including the cooling water and the steam exhausted from the core through the uniform pressure space is supplied to the vertical lattice paths. The two-phase flow ascends in the vertical lattice paths. Thus, the flow distribution for each fuel assembly can be calculated using the pressure difference between the upper end and the lower end of the core can be calculated without the need for the void fraction of the lattice paths.Type: ApplicationFiled: January 29, 2007Publication date: November 29, 2007Inventors: Masao CHAKI, Tetsushi Hino