Hitachi, Ltd.

Hitachi-Ge Nuclear Energy, Ltd.

Other

Motoo Aoyama

Junichi Yamashita

Sadao Uchikawa

Yasunori Bessho

Junichi Koyama

Masao Chaki

Renzo Takeda

Hiromi Maruyama

Akinobu Nakajima

Katsumasa Haikawa

Kunitoshi Kurihara

Osamu Yokomizo

Koji Nishida

Kumiaki Moriya

Yasuhiro Masuhara

Akihiro Yamanaka

Takaaki Mochida

Junichi Miwa

Ryoji Masumi

Yoshihiko Ishii

Yasuhiro Takahashi

Kikuo Umegaki

Junjiro Nakajima

Kazuya Ishii

Hiromasa Hirakawa

Yuichi Morimoto

Hideo Soneda

Hiroshi Nakano

Kazuo Hiramoto

Takuya Aoyagi

Kanji Kato

Junichi Sakano

Motomune Kodama

Takashi Naitou

Yuichiro Yoshimoto

Hajime Umehara

Kotaro Inoue

Masaru Sekihara

Tatsuo Hayashi

Yasuhiro Aizawa

Yukiharu Ohga

Kazuaki Kito

Kazuaki Kitou

Takeshi Mitsuyasu

Kouji Shiina

Yoko Ishibashi

Masaya Ootsuka

Mitsunari Nakamura

Michihiro Ozawa

Akiko Kanda

Tomohiko Ikegawa

Motomasa Fuse

Taro Ueki

Takao Kondo

Minoru Okura

Seiji Nemoto

Masanao Moriwaki

Yoko Yuchi

Tetsushi Hino

Tetsuo Yasuda

Kazuyoshi Miki

Tsuneyuki Hashimoto

Michiro Yokomi

Mamoru Kamoshida

Taichi Takii

Renzou Takeda

Masaya Ohtsuka

Masayuki Nagasawa

Ryou Ishibashi

Michitaka Ono

Katsuhito Takahashi

Tadahiro Ohnishi

Atsushi Zukeran

Toshinori Kawamura

Kenichi Katono

Yooko Ishibashi

Kouji Shina

Kouji Fujimura

Tomoyuki Matsumoto

Takuji Nagayoshi

Motohiko Ikegawa

Soamu Yokomizo

Naoyuki Nakadozono

Motoki Nakane

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.

Fuel assembly

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&#x3c;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.

MOX fuel assembly

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.

Core of boiling water reactor

Provided is a structure including a first member (); a second member () disposed opposite to the first member (); and a glass layer () disposed between the first member () and the second member () so as to bond the first member () and the second member (). A glass transition point of the glass layer () is lower than a temperature of the glass layer () under operation. In the glass layer (), at least either of ceramic and metallic particlesis dispersed. In a temperature region lower than the glass transition point of the glass layer (), a thermal expansion coefficient thereof falls in between thermal expansion coefficients of the first member () and the second member (). This allows thermal strain caused within the structure () to be reduced when the structure () is operated at a higher temperature than a room temperature.

Structure, electronic element module, heat exchanger, fuel rod, and fuel assembly

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.

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&#xb0; C. to 40&#xb0; C. in the second operation cycle.

Operation method of nuclear power plant

A ratio of the number of fuel assemblies loaded on a core to the number of control rod drive mechanisms is 3 or more. The fuel assembly itself contains mixed oxides of a low enrichment concentration uranium oxide containing 3 to 8 wt % in the average enrichment concentration of the fuel assembly, or mixed oxide containing not less than 2 wt %, but less than 6 wt % in the average enrichment concentration of fissile plutonium of. In the burner type BWR core on which the fuel assemblies are loaded, an average weight density of uranium, plutonium and minor actinides is 2.1 to 3.4 kg/L as a conversion at the value of unburned state.

Boiling water reactor core and fuel assemblies therefor

Reactor core

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.

Nuclear power plant and operation method thereof

Growing community of inventors

Mito, Japan

Motoo Aoyama