Foldable dual-seal nozzle dam

摘要

A nozzle dam for providing a fluid-tight seal across a primary fluid nozzle in the plenum of a nuclear steam generating vessel includes two fluid-impermeable seals, each comprising a circular three-section foldable seal plate covered with a flexible diaphragm and circumferentially encompassed by an inflatable seal member disposable in frictional sealing engagement with the inner surface of the nozzle. The center sections of the two seals are interconnected by tubular coupling means. The diaphragms are disposed on the high pressure sides of the seal plates, and the sections of each seal plate are hinged on the high pressure side. The center section of each seal plate carries two pairs of support tabs attached to the low pressure side thereof and respectively projecting from opposite ends thereof in cantilever fashion for supported engagement with a frustoconical portion of the inner surface of the nozzle.