Hitachi-Ge Nuclear Energy, Ltd.

Hiroaki Asakura

Satoshi Kanno

Hideyo Saito

Kouji Shiina

Shiro Takahashi

Fumihito Hirokawa

Sho Kuroita

Sadakatsu Sawahata

Yasuhiro Mabuchi

Shoji Hayashi

Minoru Masuda

Kenichi Nihei

A chimney arranged inside of a reactor pressure vessel of a natural-circulation boiling water reactor is provided. The chimney includes plural flow channels which guide a steam-water two-phase flow generated in a reactor core to the upper part of the reactor pressure vessel. Each of the flow channels is formed by plural flow channel separation walls whose lower-most part is supported by a chimney lattice plate. Chimney spacers that support a horizontal load are arranged between the flow channel separation walls of the adjacent flow channels. Chimney support rings that support the horizontal load are arranged at the outermost periphery of the plural flow channels that are supported by the chimney lattice plate.

Natural-circulation boiling water reactor and chimney therefor

In implementing an induction heating stress improvement (IHSI) method in a nuclear plant, cooling characteristic with respect to the inner surface of piping is improved by appropriate structure/layout of nozzles, and further, the cooling effect when applying IHSI to a real machine is verified by installing a thermometer, as well as air in the portion subjected to IHSI is removed by heating the piping prior to the execution of IHSI.

Induction heating stress improvement

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Hitachi, Japan

Hiroaki Asakura