Hitachi, Ltd.

Hitachi-Ge Nuclear Energy, Ltd.

Takao Kondo

Motoo Aoyama

Junichi Yamashita

Masao Chaki

Kumiaki Moriya

Katsumasa Haikawa

Yasuhiro Masuhara

Akihiro Yamanaka

Taichi Takii

Koji Matsumoto

Akira Konoma

Akiyuki Tsuchiya

Satoshi Takeo

Yuji Honma

Provided is a control rod motion monitoring method and a control rod motion monitoring system, in which a control rod insertion in an entire core is monitored at all time during operation of a reactor and, when an abnormality occurs, a signal is issued to a countermeasure device that automatically starts operation and an alarm is issued to prompt operation of an operator. An LPRM detector in an LPRM assembly of the entire core is divided into four channels for each height; indicated values are averaged at all time; the average indicated value is compared with a set point; and a signal is issued to a countermeasure device when an abnormality occurs.

Control rod motion monitoring system and control rod motion monitoring method

A boiling water type nuclear reactor core, in which a plurality of fuel assemblies, each enclosed in a channel box, are loaded and a plurality of control rods, each having control blades, are arranged between the channel boxes. Long blade control rods, each having control rod blades which extend in four directions, are arranged between channel boxes on diagonals of square bundle regions each formed by a plurality of fuel assemblies, and short blade control rods, each having a control rod blade length of about half of the width of one of the square bundle regions, are arranged between the channel boxes in the center of each of the square bundle regions.

Boiling water type nuclear reactor core and operation method thereof

A boiling water type nuclear reactor core, in which a plurality of fuel assemblies, each enclosed in a channel box, are loaded and a plurality of control rods, each having control blades, are arranged between the channel boxes. Latitudinal long blade control rods, each having control rod blades which extend latitudinally in four directions, are arranged between channel boxes on diagonals of square bundle regions each formed by a plurality of fuel assemblies, and latitudinal short blade control rods, each having control rod blades which extend latitudinally in four directions with each control rod blade having a latitudinal length of about half of the width of one of the square bundle regions, are arranged between the channel boxes in the center of each of the square bundle regions. The long blade control rods have a latitudinal blade length which is about twice as long as the latitudinal blade length of the short blade control rods.

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Hitachi, Japan

Takao Kondo