Regulatory approaches to, and practice of, PSA in Finland, France, Spain, Sweden, Switzerland, the United Kingdom, and the United States of America

Performing level-1 probabilistic safety analyses (PSA) is the established standard in most countries using nuclear power. In addition, level-2 PSA has become more and more widespread over the past few years. However, regulatory requirements and practice differ from country to country, especially with respect to level-2 analyses. In an effort to determine these differences more precisely, the ISaR Institute for Safety and Reliability, on behalf of VGB PowerTech Service GmbH, conducted a study of these seven countries: Finland, France, Spain, Sweden, Switzerland, the United Kingdom, and the United States. The study focused on level-2 PSA carried out by plant operators within the framework of periodic safety reviews. The findings of the study are based on extensive interviews of at least one expert each on the operators' and the authorities' sides for each of the seven countries. Points taken into account in particular included the criteria imposed by regulators on PSA carried out by operators; the rank of PSA within the regulatory framework; the required versus the actual scopes of analysis; the objectives and uses of PSA; reviews of the analyse; the methods employed.