Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Eishi Ibe

Shunsuke Uchida

Eiichi Nishimura

Fumio Kawamura

Motoaki Utamura

Katsumi Ohsumi

Yamato Asakura

Tatsuo Hayashi

Masaharu Sakagami

Minoru Miki

Masao Kitamura

Hidetoshi Karasawa

Koichi Saito

Maroto Nagase

Yoshinori Chiba

A direct cycle type atomic power plant provided with a means for suppressing transfer of radioactive nitrogen compounds generated by nuclear reaction in the core from the reactor water to steam, where an increase in the dose rate in the main steam system and the turbine system due to carry-over of radioactive nitrogen atom, .sup.16 N, generated in the core can be suppressed, and the radioactivity therein can be reduced.

Direct cycle-type atomic power plant with means for suppressing transfer

A control rod for a boiling-water reactor having blades arranged in the form of a cross in transverse cross section includes a plurality of poison tubes disposed therein. Boron carbide powder which is a neutron absorbing material causing an (n, .alpha.) reaction to take place is charged in the poison tubes. The control rod has plates of Hf-Zr alloy arranged in the blades in a position nearer to a forward end of the control rod at which the control rod is inserted in a reactor core than the poison tubes. The plates of Hf-Zr alloy are formed of an alloy of Hf having a large neutron absorption cross section and Zr having a small neutron absorption cross section. The concentration of Hf in the plates of Hf-Zr alloy is successively reduced in going from an end thereof adjacent the poison tubes toward and end thereof at the inserting end of the control rod. The plates of Hf-Zr alloy and the poison tubes have the same neutron absorbing capacity at the boundary therebetween at which they are in contact with each other.

Control rods and method of producing same

Growing community of inventors

Katsuta, Japan

Eishi Ibe