Method of repairing shroud support and repair apparatus thereof

摘要

A shroud support of a BWR includes a shroud support cylinder, shroud support legs welded to a bottom of a reactor pressure vessel (RPV) and a shroud support cylinder, and an annular shroud support plate disposed between the RPV and the shroud support cylinder and welded to the RPV and the shroud support cylinder. A support apparatus is set a CRD housings installed to the bottom of the RPV. A rail guide member horizontally set to the support apparatus reaches directly below the shroud support plate through an opening between the shroud support legs. A bent rail is set on the rail guide member. The bent rail setting a repair device is pushed out along the rail guide member toward the RPV through the opening portion by the rail push-out apparatus set on the support apparatus. The bent rail is spread at directly below the shroud support plate.

主权项

1. A method of repairing a shroud support, comprising the steps of:
setting each of support apparatuses on each upper end of a plurality of control rod drive mechanism housings attached to a bottom of a reactor pressure vessel, in said reactor pressure vessel; positioning horizontally a rail guide member rotatably attached to each of said support apparatus by rotating said rail guide member in an axial direction of said reactor pressure vessel; setting a rail on each of said rail guide members; moving each of said rails, which include said rail on which said repair device is set and said rail on which said repair device is not set, toward an inner surface of said reactor pressure vessel along each said rail guide member, said rails setting on each of said rail guide members; setting a plurality of said moved rails along a weld of said shroud support in a reactor pressure vessel over either an entire perimeter on an inner circumference of said reactor pressure vessel or a part of said entire perimeter; and performing repair operation of said weld of said shroud support by a repair device that is moved along said plurality of rails set along said weld of said shroud support.