Mitsubishi Heavy Industries Limited

Kensuke Tsuboi

Takeshi Yamamoto

Hideshi Sakashita

Tsuyoshi Nishimura

Tomonobu Sato

A nozzle repair method and a nuclear reactor vessel include: removing a trepanning portion () as a connection portion with respect to an in-core instrumentation cylinder () in a groove-welding portion (); removing the in-core instrumentation cylinder () from a semi-spherical portion () as a lower end plate; forming a surface buttered-welding portion () by buttered-welding the surface of the groove-welding portion (); forming a welding groove () by grooving the surface buttered-welding portion (); inserting a new in-core instrumentation cylinder (A) provided with a circumferential groove portion () outside an instrumentation equipment guide passage () into an attachment hole (); and fixing the new in-core instrumentation cylinder (A) by groove-welding the welding groove (). Accordingly, since the nozzle welding area is suppressed to a predetermined range, the workability of the repair is improved.

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Tokyo, Japan

Kensuke Tsuboi