Patents by Inventor Tsugio Yokoyama
Tsugio Yokoyama 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: 8711997Abstract: A reactor core is immersed in a liquid metal coolant in a core barrel of a liquid metal cooled reactor. The reactor core includes a plurality of fuel assemblies contained in the core barrel, a neutron absorber that absorbs a neutron in the reactor core, and a neutron moderator that moderates a neutron therein so as to control a reactivity of the reactor core. The neutron absorber and the neutron moderator constitute a mixture contained in reactivity control assemblies of the reactor core in the liquid metal coolant prior to immersion of the reactor core. The neutron moderator is composed of zirconium hydride.Type: GrantFiled: January 30, 2012Date of Patent: April 29, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20120183113Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: January 30, 2012Publication date: July 19, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Tsugio YOKOYAMA, Hisato Matsumiya, Yasushi Tsuboi
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Patent number: 8126105Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without performing control of a reflector lifting speed and that of a water flow rate. The above fast reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector which is provided outside the reactor core and which is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the reactor core. The neutron reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the neutron reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located from the bottom to a place between one fourth and one half of the height of the neutron reflector from the bottom end thereof.Type: GrantFiled: November 19, 2010Date of Patent: February 28, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Publication number: 20110194664Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: January 13, 2011Publication date: August 11, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Tsugio YOKOYAMA, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20110103535Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without performing control of a reflector lifting speed and that of a water flow rate. The above fast reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector which is provided outside the reactor core and which is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the reactor core. The neutron reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the neutron reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located from the bottom to a place between one fourth and one half of the height of the neutron reflector from the bottom end thereof.Type: ApplicationFiled: November 19, 2010Publication date: May 5, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsugio YOKOYAMA, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Patent number: 7864913Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without controlling a reflector lifting speed and a water flow rate. The fast reactor has a neutron reflector provided outside the reactor core and which is moved in a vertical direction for adjusting neutron leakage to control the reactivity of the reactor core. The neutron reflector is moved in an upward direction with the change in reactivity caused by fuel burn-up. At least a part of a lower region of the neutron reflector may be a region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located at the bottom of the neutron reflector and extends from between one fourth and one half of the height of the neutron reflector.Type: GrantFiled: February 18, 2005Date of Patent: January 4, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Patent number: 7773716Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without controlling reflector lifting speed and a water flow rate. The reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector provided outside the core and is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the core. The reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located between the bottom and one fourth and one half of the height of the neutron reflector.Type: GrantFiled: July 2, 2008Date of Patent: August 10, 2010Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Publication number: 20100067641Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: November 24, 2009Publication date: March 18, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20090080586Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: November 13, 2008Publication date: March 26, 2009Applicant: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20090010374Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: May 28, 2008Publication date: January 8, 2009Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yohei NISHIGUCHI, Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20080273650Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without performing control of a reflector lifting speed and that of a water flow rate. The above fast reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector which is provided outside the reactor core and which is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the reactor core. The neutron reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the neutron reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located from the bottom to a place between one fourth and one half of the height of the neutron reflector from the bottom end thereof.Type: ApplicationFiled: July 2, 2008Publication date: November 6, 2008Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsugio Yokoyama, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Patent number: 7139352Abstract: A reactivity control rod adapted to be used in a reactor core of a fast reactor and disposed at a substantially central portion of the reactor core for controlling a reactivity therein. The reactivity control rod includes a wrapper tube surrounded by a plurality of fuel rods in a reactor core, and a plurality of neutron absorber rods arranged in the wrapper tube. At least one of the plurality of neutron absorber rods includes a cladding tube and a mixture filled in the cladding tube. The mixture is composed of a neutron absorber that absorbs a neutron and a neutron moderator that moderates the neutron.Type: GrantFiled: December 28, 2000Date of Patent: November 21, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Yohei Nishiguchi, Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Publication number: 20060210010Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: March 17, 2006Publication date: September 21, 2006Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yohei Nishiguchi, Tsugio Yokoyama, Hisato Mitsumiya, Yasushi Tsuboi
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Publication number: 20050220251Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without performing control of a reflector lifting speed and that of a water flow rate. The above fast reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector which is provided outside the reactor core and which is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the reactor core. The neutron reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the neutron reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located from the bottom to a place between one fourth and one half of the height of the neutron reflector from the bottom end thereof.Type: ApplicationFiled: February 18, 2005Publication date: October 6, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsugio Yokoyama, Mitsuaki Yamaoka, Yasuyuki Moriki, Ryoma Kato, Yasushi Tsuboi, Atsuko Matsuda
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Publication number: 20020075983Abstract: In a nuclear reactor in which a primary coolant is contained, the primary coolant moves upwardly from the core by an operation thereof. An annular steam generator is arranged in an upper side of the core into which the upwardly moving primary coolant flows and transfers heat in the primary coolant into water therein to generate a steam. A passage structure defines a coolant passage for the primary coolant to an outside of the core. The heat-transferred primary coolant in the annular steam generator flows downwardly in the coolant passage so as to flow into the core, thereby moving upwardly. A reactor vessel is arranged to surround the coolant passage so as to contain the core, the annular steam generator and the passage means therein.Type: ApplicationFiled: December 28, 2000Publication date: June 20, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yohei Nishiguchi, Tsugio Yokoyama, Hisato Matsumiya, Yasushi Tsuboi
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Patent number: 6088420Abstract: In a reactor core, there is charged a number of fuel assemblies composed of a channel box and a fuel bundle disposed therein, in which fuel rods adjacent to each other are arranged so as to provide a triangular shape and a ratio of a coolant channel cross section to a fuel cross section is set to be 1 or less.Type: GrantFiled: May 4, 1998Date of Patent: July 11, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Ritsuo Yoshioka, Yasushi Tsuboi
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Patent number: 5610956Abstract: A fast reactor core in which a coolant flows comprises a plurality of fuel assemblies each loaded with a fissionable material and a plurality of gas sealed assemblies disposed between the fuel assemblies and sealed with a gas, wherein a surface level of the coolant in the gas sealed assembly changes from an axially upper portion including a core top level to an axially lower portion at a time of core power increase or a core coolant flow quantity decrease. Each of the gas sealed assemblies includes an inner cylindrical member for reducing a horizontal cross sectional area of the flow of the coolant at a portion in height corresponding to an axial central portion of the core and the cylindrical member includes a member for generating heat by radiation.Type: GrantFiled: September 8, 1994Date of Patent: March 11, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Tsugio Yokoyama, Takeshi Shimizu
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Patent number: 5420897Abstract: A fast reactor comprises a core composed of nuclear fuel, a core barrel surrounding an outer periphery of the core, an annular reflector surrounding an outer periphery of the core barrel, a partition wall structure surrounding an outer periphery of the annular reflector and supporting the core barrel by a supporting structure arranged radially of the fast reactor, the partition wall structure constituting an inner wall of a coolant passage for a primary coolant, a neutron shield surrounding an outer periphery of the partition wall structure and disposed in the coolant passage, a reactor vessel surrounding an outer periphery of the neutron shield and having an inner wall constituting an outer wall of the coolant passage, and a guard vessel surrounding an outer periphery of the reactor vessel.Type: GrantFiled: July 29, 1993Date of Patent: May 30, 1995Assignees: Kabushiki Kaisha Toshiba, Central Research Institute of Electric Power IndustryInventors: Shigeo Kasai, Masatoshi Kawashima, Tsugio Yokoyama, Katsutada Aoki, Norihiko Handa, Megumu Yoshida, Morihiko Sato, Hiroshi Nakamura, Tohru Iijima, Junko Matsuda, Kenji Ogura, Makoto Ono, Sadao Hattori