On the trustworthiness of safety assessments for nuclear pressure vessels

The progress made in improving the safety against failure of nuclear pressure vessels has relied, among other things, on intangible factors like good workmanship, tacit knowledge, sense of responsibility, etc. This has long been recognized by those for whom this effort is made. The trust of the public and decision-makers is based on an appreciation of the awareness of the technological community also of the importance of non-technical, critical aspects. In order to maintain the trustworthiness of safety assessments in this respect it is therefore necessary to follow up previous research and development work with studies of problems of modelling for probabilistic calculations, collection of data on defect detection, intelligence concerning inconceivable events, competence and managerial aspects. (author)