Nuclear Power Plant Benefits from innovative Repair Technology

摘要

Because of its location, a through-wall leak on a pressure vessel nozzle required a unique approach to its repair. In the fall of 2003, the author faced a somewhat unusual repair at Entergy Nuclear Northeast. The Pilgrim Nuclear Power Station (PNPS) near Plymouth, Mass., identified a stream of water leaking from a weld that attaches a nickel alloy cap to a nozzle on the reactor pressure vessel - Fig. 1. In recent years, nickel alloys (Alloy 600 and E NiCrFe-3) used in these environments have been identified as being susceptible to inter-granular stress corrosion cracking. Several plants have been forced to replace or repair these materials using structural weld overlays. This repair technology has been used on stainless steel and Alloy 600 for more than two decades now and is well accepted by the regulators, industry, and insurers.