30 IWE and IWL

Chapter 30 originally authored by the late Robert F. Sammataro (a well-known and respected colleague well-versed in ASME Codes and Standards) and now updated by Jim E. Staffiera, addresses Subsections IWE and IWL for nuclear containment vessels. Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Plants, specifies requirements for preservice and inservice examination∕inspection, repair∕replacement activities, and testing of Class MC (metal containment) pressure-retaining components and their integral attachments and repair∕replacement activities and testing of Class CC (concrete containment) pressure-retaining components and their integral attachments for BWRs and PWRs. Similarly, Subsection IWL, Requirements for Class CC Concrete Components of Light-Water Cooled Plants, specifies requirements for preservice and inservice examination∕inspection, repair∕replacement activities, and testing of the reinforced concrete and the post-tensioning systems of Class CC (concrete containment) components for BWRs and PWRs. Together with Subsection IWA, General Requirements, a comprehensive basis is provided for ensuring the continued structural and leak-tight integrity of containments in nuclear power facilities.

Subsections IWE and IWL also provide requirements to ensure that critical areas of primary containment structures∕components are inspected to detect degradation that could compromise structural integrity. These two Subsections have received significant attention in recent years since the Nuclear Regulatory Commission (NRC) mandated nuclear-industry compliance with these two Subsections of the Code through publication of revised Paragraph 55(a) of Title 10, Part 50, of the Code of Federal Regulations [10 CFR 50.55(a)] in September, 1996. In incorporating these two Subsections into the Regulations, the NRC identified its concern with the increasing extent and rate of occurrence of containment corrosion and degradation. Since that time, numerous additional changes have taken place in all aspects of nuclear power plant inservice inspection requirements, not the least of which have been those for nuclear containment vessels. With increasing emphasis in the nuclear industry on plant life-extension, these changes have resulted in several initiatives currently moving through the ASME Code ‘consensus-committee’ process, including action items addressing the need for more appropriate and effective examinations∕inspections and the expanded use of risk-informed inservice inspection activities. This updated Chapter 30 introduces the latest Commentaries for Subsections IWE and IWL, important documents for users of the Code because of the background information and technical justification provided regarding the reasons for changes made to these two subsections over the years. As noted in the Introduction to this book, the user is cautioned that these documents are the opinions of individuals only. These documents are not products of the ASME Code Committee consensus process, and thus do not represent ASME Code Committee positions.