30 Lessons Learned: NRC Experience

The objective of this chapter is to provide some highlights on the recent issues and lessons learned by the Nuclear Regulatory Commission (NRC) for the safety related and safety significant nuclear power plant components, which utilize the ASME Boiler and Pressure Vessel Codes, Sections III and XI. These include issues related to 2011 Japan Earthquake that directly impacted the Fukushima Nuclear Plant, and also led the regulatory bodies worldwide to take a closer look at the emergency systems for any needed changes for beyond the design basis events. This chapter also provides some information on environmental assisted fatigue of nuclear components exposed to Light Water Reactor (LWR) environments, buried piping leakage and contamination issues, the issues related to High density polyethylene (HDPE) as an alternate piping material for the replacement of buried steel piping, the issues and lessons learned related to BWR steam dryers subjected to flow induced vibration loading associated with extended power uprate (EPU) conditions, the current conclusions related to quasi-laminar indications in reactor pressure vessel ring forgings, steam generator tube leaks and fluid elastic instability, and lessons learned from Operating plants experience for consideration in new nuclear power plant (NPP) construction.