Patent Number: 056053614
Section: abstract

The invention disclosed herein provides nozzles for vessels such as a pressurizer vessel, reactor vessel or piping in a nuclear power facility, and methods for attaching and sealing the nozzles to the vessels without any welding at all, i.e., without using a structural or seal weld. The nozzles are clamped or bolted to the vessel or attached by an interference fit, and a mechanical seal is obtained using gasket material and/or contacting, preferably polished, metal surfaces. Some embodiments of clamping the nozzle to the vessel comprise tightening a nut on the threaded end of the nozzle projecting from the bore in the vessel against the vessel, and structure which prevents the nozzle from being withdrawn through the bore, thereby clamping the nozzle against the vessel. Another embodiment of clamping a nozzle to the vessel comprises a sleeve threaded in the bore and forcing an interfering portion of the nozzle body into engagement with the bore. In still another clamping embodiment, an exterior flange (attached to or engaged with the nozzle) is clamped to the vessel by bolts and interferring portions of the nozzle and the bore. Embodiments of bolting the nozzle to the vessel include threading the nozzle in the bore, and structure which prevents the nozzle from being withdrawn through the bore. The engaging structure may comprise an interior flange attached to the nozzle surrounding the bore on the interior of the vessel, or interfering portions of the nozzle and the bore. The nozzle may also be mechanically sealed with an O-ring arrangement. Attaching a nozzle with an interference fit may be accomplished by creating a temperature gradient between a larger OD nozzle and a smaller ID bore sufficient to enlarge the diameter of the bore, reduce the diameter of the nozzle, or both to allow the nozzle to be inserted into the bore and then reducing the temperature gradient The invention also provides a nozzle arrangement which is clamped to a large bore pipe.