Safety principles for advanced plant

The essential safety principles which should be applied when considering new designs or developments of existing designs for the 'advanced plant' are considered under the headings of 1) reactivity control, 2) heat removal from the core, 3) containment and 4) materials properties. How these principles apply in practice is considered by reference to both revolutionary and evolutionary advanced designs. Revolutionary designs claim that they utilise 'inherent' or 'passive' safety features which make them benign and incapable of causing harm to people. Evolutionary designs follow a route of improvements for existing, well developed designs which incorporate many elements of 'inherent' or passive safety but rely upon the basis of experience gathered in operating existing designs over several decades. We argue that no reactor design to date is truly inherently safe and that all must rely on engineered features. Application of the safety principles provides criteria against which to judge such designs. This leads to the conclusion that our current best judgement is that the evolutionary route provides the best way forward on both safety and economic grounds. (author)