Kabushiki Kaisha Toshiba

The Tokyo Electric Power Company, Incorporated

Mikihide Nakamaru

Hiroshi Yamazaki

Tadashi Narabayashi

Shinichi Morooka

Kenji Arai

Takehiko Saito

Hideaki Heki

Kouji Hiraiwa

Makoto Yasuoka

Seijiro Suzuki

Satoru Oomizu

Tsuyoshi Shimoda

Yutaka Asanuma

Yukio Takigawa

Michitsugu Mori

Yutaka Takeuchi

Mika Tahara

Ryoichi Hamazaki

Shuichi Ohmori

Kenji Kumagai

Nobuaki Abe

Miyuki Akiba

Akira Murase

A boiling water reactor has a reactor pressure vessel and a through piping. The reactor pressure vessel includes a main body trunk and an openable upper lid covering an upper open end of the main body trunk from above. The through piping penetrates lateral side of the main body trunk and has an opening section at a same level with or higher than the upper open end of the main body trunk in the reactor pressure vessel. The through piping may be connected to the sump arranged outside the reactor pressure vessel in the dry well. The through piping may be further connected to the suppression pool in the wet well and/or to the water level gauge in the dry well.

Boiling water reactor

A natural-circulation type boiling water reactor includes a plurality of divided chimneys provided above a reactor core and a number of fuel assemblies are charged in the reactor core. The natural-circulation type boiling water reactor is provided with a pressure equalization structure arranged on rectangular-columnar lattice plates of the divided chimneys for equalizing pressures in divided chimney portions so as to equalize the pressures of the divided chimneys with the pressure equalization structure.

Natural circulation type boiling water reactor

The present invention is to provide a reactor core that allows a nuclear plant to continuously operate for a long term period, for example 15 years or longer, without requiring any fuel exchange, reduces the duration and number of maintenance steps involved in regular plant inspections, markedly improves plant availability and economic efficiency, and is effective in terms of nuclear nonproliferation. A plurality of fuel assemblies, themselves obtained by arranging fuel rodsand water rodsin square lattices, are arranged in a square lattice at a certain pitch. The bladesof a cross-shaped (cruciform) control rodin a cross section are inserted into four adjacent spaces formed by four fuel assembliesfacing each other. A value of 0.06 cmor greater is selected for the ratio (B/S) of the width (B) of each blade on the cruciform control rodand the surface (S) of the fuel lattice defined by the surface area of a square whose side is equal to the pitch between the fuel assemblies

Reactor core and method for operating nuclear reactor

The present invention provides a boiling water reactor nuclear power plant in which a reactor core support plate, upper grid plate, and a reactor core consisting of fuel assemblies supported by these plates are provided in the inner base portion of a nuclear reactor pressure vessel. Control rod guide tubes and a reactor core shroud are positioned over the upper grid plate, and a control rod drive mechanism is provided further above same, whereby the control rods can be inserted from above the reactor core, and natural circulation of cooling water inside the reactor can be achieved by means of a chimney effect of the control rod guide tubes. According to the above structure, there can be provided a compact and economical nuclear power plant.

Boiling water reactor nuclear power plant and its construction method

A feed water heating system for heating a feed water for a power-generating plant having a steam turbine, a condenser and a steam generator, comprises: a steam injector unit for receiving a plurality of bled steams having different pressures extracted from the steam turbine and an effluent water discharged from the condenser to mix the effluent water with the plurality of bled steams to raise the temperature and pressure of a mixture of the effluent water with the plurality of bled steams to deaerate and discharge the temperature and pressure raised mixture. The steam injector unit comprises: a multistage steam injector having a plurality of steam injectors connected in series for receiving one of the plurality of bled steams and a feed water to mix the one of the plurality of bled steams with the feed water to raise the temperature and pressure of a mixture of the one of the plurality of bled steams and the feed water to discharge the temperature and pressure raised mixture; a cylindrical container for housing therein the multistage steam injector; and a jet centrifugal deaerator, provided downstream of the multistage steam injector, for receiving a feed water discharged from the multistage steam injector and the bled steams to apply a centrifugal force to the feed water and the bled steams to deaerate the feed water to spatially separate a deaerated feed water from the bled steams to discharge the deaerated feed water.

Feed water heating system for power-generating plant

A separator/injector having an outlet pressure higher than an inlet pressure thereof is introduced instead of the dynamic equipment for a reactor recirculation system that is necessary in the prior art, to achieve both liquid-vapor separation and forced circulation. A jet pump and a recirculation flow-rate control valve are provided in a lower portion of a downcomer portion of a reactor pressure vessel. A shroud head has a double-walled structure, a two-phase liquid-vapor flow that is flowing from a lower portion of the lower shroud head is accelerated by an accelerator nozzle of the separator/injector, and a liquid component of the thus-separated flow is increased in pressure and guided into a jet pump through a space formed between the double shroud heads. Alternatively, a circular cylindrical separator/injector in which the steam nozzle and diffuser are disposed in a helical form in close proximity to the inner wall of a circular tube above the stand pipe could be provided instead of this separator/injector.

Steam separator, nuclear power generation plant, and boiler apparatus

Growing community of inventors

Fujisawa, Japan

Mikihide Nakamaru