TOWARDS THE RISK-INFORMED APPROACH

摘要

The transition to a risk-informed approach requires a good understanding of the initial deterministic approach. Therefore this lecture starts with a description of the deterministic approach, the role of the safety analysis, defense-in-depth, and deterministic safety principles. Then it is argued that a deterministic approach is not enough when efficiency in the use of available resources for safety is a must. PSA is shown to be a systemic approach that provides a holistic view of the safety of the plants and therefore it has the intrinsic elements to deal with an emergent property of a system as safety is. To afford an appropriate use of PSA the strengths and drawbacks of PSA are analysed and actions to reduce the later are indicated. Then uses of PSA are discussed ranging from interpretations of present deterministic framework to the overhaul of the whole regulatory framework. The use today of PSA results as the sole figure of merit in what could be a risk-based framework is discouraged. However use of PSA in a risk-informed approach is considered beneficial and main activities are commented. Finally a guess about the future of PSA is included.