Technical issues limiting the long-term integrity of water reactor pressurized components and their fittings

The paper reports on a recent workshop conducted by the Principal Working Group on Primary Circuit Integrity of the OECD-NEA Committee on the Safety of Nuclear Installations. The workshop sought to identify broad technical issues that required further study as a contribution to determining, in a safety context, the long-term integrity and hence service life of water reactor pressurized components and their important fittings. The workshop identified no specific technical limitations which would rule out on structural integrity grounds the extension of service lives for pressurized components and associated fittings beyond current expectations. Rather, there are a number of areas in which more understanding and, in particular, better and more realistic property and performance data will be required for assessment purposes if the necessary confidence in maintaining adequate safety margins is to be obtained. The Principal Working Group will be taking actions on a number of these matters