The NRC is modernizing nrc.gov with an updated design and improved navigation to enhance usability. We are committed to a smooth transition and will work to minimize any disruption. The site may be briefly unavailable at times during launch. Thank you for your patience.
Spotlight
Reactor Pressure Boundary Integrity Issues for Pressurized Water Reactors
Several instances of primary water stress corrosion cracking (PWSCC) of nickel based alloys have been reported in the reactor pressure boundaries of pressurized water reactors (PWRs). The NRC is investigating the effect of PWSCC on the structural integrity of reactor pressure boundaries at all U.S. PWRs. NRC regulatory actions for Reactor Pressure Vessel (RPV) Upper Head, RPV Bottom Head, the Pressurizer, Reactor Coolant Systems Welds, and Overview are provided in the links below:
Related Information
Page Last Reviewed/Updated Tuesday, September 08, 2026
Page Last Reviewed/Updated Tuesday, September 08, 2026