Challenges left in the areas of materials ageing and plant modernisation

For Nuclear Power Plant systems, structures and components (SCO. the aspect of ageing is being discussed to a high level of detail and sufficient work is being performed to achieve a common understanding complemented by the well known glossary for Nuclear Power Plant ageing and the IAEA guidance documents. The intention of this paper is to look at the issue of Plant Ageing and Plant Modernisation in a more simultaneous way. illustrated by a few examples. Plant Ageing Management is concentrating many times in the technical assessment on the question: Do the systems, structures and components (SSC) function according to regulatory criteria? Plant Modernisation provide usually extra safety margins. This has been proven very useful in many cases of unforeseen events, it pushes the general attitude in the right direction (improving plant instead of improving knowledge about the plant) and may help our credibility with respect to public acceptance issues. As subjective statements the predictability of the relevant ageing mechanisms are characterised and areas identified where research and development eg as part of the 5th Framework program could provide a major contribution.