The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 02, 2000
Filed:
Feb. 20, 1998
Koichi Kurosawa, Hitachi, JP;
Eisaku Hayashi, Hitachi, JP;
Sadato Shimizu, Hitachinaka, JP;
Minoru Ootaka, Takahagi, JP;
Fujio Yoshikubo, Mito, JP;
Ren Morinaka, Hitachi, JP;
Masayuki Nishino, Hitachinaka, JP;
Noboru Chiba, Tokai-mura, JP;
Kunio Enomoto, Tokai-mura, JP;
Kazunori Sato, Kure, JP;
Hitachi, Ltd., Tokyo, JP;
Babcock-Hitachi Kabushiki Kaisha, Tokyo, JP;
Abstract
A preventive maintenance apparatus for structural members inside a nuclear reactor pressure vessel includes a ring-shaped guide rail having a plurality of lugs which is placed on an upper flange of a core shroud provided inside a reactor pressure vessel. At least some of lugs separately engage with a plurality of guide rods provided on an inner surface of the reactor pressure vessel. A turntable is rotated on the guide rail. A first discharging nozzle moving apparatus placed on the turntable moves a first discharging nozzle for adding compressive remaining stress to an outer surface of the core shroud in a radial direction of the core shroud and in an axial direction of the core shroud. A second discharging nozzle moving apparatus placed on the turntable moves a second discharging nozzle for adding compressive remaining stress to an inner surface of the core shroud in a radial direction of the core shroud and in an axial direction of the core shroud.