Kabushiki Kaisha Toshiba

Tsuyoshi Shimoda

Kenji Arai

Takehiko Saito

Tadashi Narabayashi

Hideaki Heki

Kouji Hiraiwa

Mikihide Nakamaru

Shinichi Morooka

Seijiro Suzuki

Satoru Oomizu

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

Growing community of inventors

Yokohama, Japan

Tsuyoshi Shimoda