Kabushiki Kaisha Toshiba

Yoshio Hamamoto

Hiromi Kato

Satoshi Okada

Masaki Yoda

Masataka Tamura

Wataru Kono

Osamu Yamaguchi

Masahiro Takeuchi

Takuya Uehara

Takeshi Maehara

Hiroyuki Miyasaka

Yoshinobu Makino

Katsunori Shiihara

Masakazu Abura

Yuuichi Motora

Taiji Kobayashi

Tatsuya Ishigaki

Yoshimi Tanaka

An underwater welding apparatus includes: an underwater welding head provided underwater and having, at its leading end, a nozzle section from which laser light is emitted; a shied cover formed of an elastic member and provided around the nozzle section so as to form, at the leading end of the underwater welding head, a space where water is excluded by shield gas; and an expansion/contraction member having a discharge hole for discharging water and shield gas containing metal dust particles from an inside of the shield cover, the discharge hole being increased in diameter as pressure inside the shield cover rises, while being reduced in diameter as the pressure inside the shield cover falls.

Underwater welding apparatus and underwater welding method

A heating laser beam is emitted to a cracked portion to remove moisture from the cracked portion, and subsequently, a welding laser beam is emitted to the cracked portion to heat and melt the cracked portion. The heating laser beam and the welding laser beam are emitted to an entire surface of the cylindrical body inside the reactor such as a stub tube penetrating through and fixed to a reactor bottom portion and a crack of the welded portion between the cylindrical body and the reactor bottom portion to thereby prevent a new crack from occurring and reactor water from leaking.

Reactor bottom repairing method

A method of sealing a surface crack in a member is provided includes steps of irradiating a region of the member at which the crack is produced with a heating laser beam so as to heat the region to a temperature lower than a melting point of the member, and then irradiating a region of the member at which the crack is produced with a welding laser beam subsequent to irradiation of the heating laser beam so as to heat the region to a temperature higher than or equal to the melting point of the member, thereby sealing an opening of the surface crack of the member.

Surface crack sealing method

Growing community of inventors

Yokohama, Japan

Yoshio Hamamoto