Reactor pressure vessel surveillance

摘要

A reactor pressure vessel (RPV) is designed, manufactured and operated in a such a manner that it should not fail in service. To resist failure, its steel structure must remain ductile and not become brittle. A sudden failure of an RPV could be catastrophic even before considering the contents of the pressure vessel, because of the sudden release of a large amount of depressurising energy. Fracture resistance or fracture toughness is the relevant material property in structural integrity assessment of the RPV. Before the RPV enters service, structural integrity depends upon design and construction to recognised and well-established codes, the use of carefully-specified and -tested, highest-quality materials, fabrication using tried-and-tested procedures, a comprehensive quality assurance programme and extensive ultrasonic inspection during fabrication. The importance of this last aspect is highlighted by the economic impact and safety concerns of the hydrogen flakes discovered in the RPVs of Doel 3 and Tihange 2.