Abstract: A mounting arrangement for mounting a device in an opening is disclosed. The arrangement comprises an outer sleeve, an inner sleeve arranged inside the outer sleeve, and an adjustment ring arranged inside the outer sleeve. A flange is arranged at a first end of the outer sleeve, arranged to receive said device. The flange is adapted to abut an outer surface of the structure. The inner sleeve is arranged in threaded engagement with the adjustment ring or with the outer sleeve. The adjustment ring comprises a fixing wing extending outwardly through a longitudinally extending aperture in the outer sleeve, the fixing wing having an abutment portion adapted to abut an inner surface of the structure. By relative rotary motion of the inner and outer sleeve, the adjustment ring is movable along a longitudinal direction of the arrangement for adjustment to a thickness of the structure.

Abstract: A clamp assembly prevents separation of a thermal sleeve penetrating a nuclear reactor pressure vessel wall and a jet pump riser elbow welded one to the other and lying within an annular space between the pressure vessel wall and core shroud. The clamp assembly includes a pair of heads having semi-cylindrical recesses. Pins project inwardly from each of the heads in the semi-cylindrical recesses and have axes which lie parallel to one another. By using actuators mounting multiple electrodes, holes may be formed in situ in the adjoining ends of the thermal sleeve and elbow. Once the holes are formed, the heads can be applied in situ with the pins being received through the holes and the heads clamped to one another. Thug, the pins in each of the sleeve and elbow prevent separating movement of the sleeve and elbow in the event of failure of the welded joint therebetween.