Living PSA and its Use in the Nuclear Safety Decision-making Process

         Probabilistic safety analyses (PSAs) for many of the nuclear power plants throughout the world are being maintained as "living PSAs" (LPSAs), being updated to take account of changes to the design and operation of the plant, improvements in the understanding of how the plant behaves in fault situations and improved PSA methods, models and data. One of the specific applications of a living PSA is the risk monitor, used by operators and regulators to provide risk information employed in the decision-making process to ensure the safe operation of nuclear power plants. Since the first risk monitors were put into operation in 1988, the number of risk monitors worldwide has increased rapidly. By the end of 2003 there were more than 110 in operation and this figure should increase to over 150 when those monitors being developed are placed in service.         Combining these two technical opinion papers into a single publication provides the reader - notably senior researchers and industry leaders, nuclear safety regulators, nuclear power plant operators - with a concise assessment of the current state of the art, thus enabling better analysis when evaluating proposals or the development of these applications.         Also included: Development and Use of Risk Monitors at Nuclear Power Plants (No. 8)      