Role of risk assessment: Risk-informed regulations and requirements for severe accident and risk assessment research

The licensing procedures of nuclear power plants in the Western world, because of their historical development, are based on deterministic approaches incorporating extremely conservative assumptions about risk assessment. The advanced development and application of probabilistic safety assessments (PSA) has broadened the range of aspects under which to evaluate the risk and risk factors for nuclear power plants. Both for regulatory authorities and for plant operators, PSA pinpoint the relevance of risk factors, thus allowing the factors to be taken into account to be assigned higher priority, while secondary factors are given lower priority. Licensing procedures more and more are seen to include PSA and PSA findings. However, there is still need for more research and increased application in this field.