UK Surveillance Schemes

摘要

The United Kingdom has included surveillance schemes in nuclear reactors since Calder Hall started in 1957. Early experience in Magnox reactors showed their importance, and sampling schemes have been developed over the years to reflect improvements in the understanding of irradiation damage mechanisms and methods of structural integrity assessment. The wide range of exposure conditions in these reactors led to the use of surveillance data for developing predictive models. The results of Magnox surveillance have carried through to the steel components in the UK advanced gas-cooled reactors. An extensive surveillance scheme has been included in the Sizewell B pressurized water reactor and captured many of the lessons learned. UK naval reactors also include surveillance samples, but the small size of the reactors and their refueling schedules limit the type of specimens. The approach has been to design the tests to represent the entire reactor fleet with samples in a particular reactor, also including earlier and later ones. Although many lessons have been learned in the development of UK surveillance schemes, key points include the advantages gained from testing samples appropriate to design needs in reducing the need for property-to-property correlations, integration across a fleet, and particularly the provision of plentiful archive material (and retention of tested material), both for control samples and for new tests that may be stimulated by changes in technology and understanding over time.