Method and device for replacing an adapter for a nuclear reactor vessel closure crossing

摘要

The replacement is carried out from an operating region located above the convex face (1a) of the head. The adaptor to be replaced is machined after removing its control mechanism (13) and a heat sleeve (4), by introducing suitable tooling (14) via the upper end of the adaptor (3') to be replaced. In succession, the lower part of the adaptor and a part of the weld of this adaptor are machined, a narrow chamfer is machined in the weld of the adaptor to be replaced, the remaining part of the adaptor (3') to be replaced is rebored inside the head (1), the adaptor is extracted, a replacement adaptor is fitted by cold binding (shrinking) and the replacement adaptor is welded.