Development And Application Of Level 1 Probabilistic Safety Assessment For Nuclear Power Plants

The objective of this Safety Guide is to provide recommendations for meeting the IAEA safety requirements in performing or managing a level 1 probabilistic safety assessment (PSA) project for a nuclear power plant. These recommendations promote technical consistency among level 1 PSA studies and support applications of PSA and risk informed decision making. The Safety Guide's scope encompasses all operational conditions of the plant and potential initiating events and hazards.

The objective of this Safety Guide is to provide recommendations for meeting the requirements of GSR Part 4 (Rev. 1) in the development and application of Level 1 Probabilistic Safety Assessments (PSAs) for nuclear power plants (NPPs). The recommendations provided in this publication promoting technical consistency among Level 1 PSA studies, in order to provide reliable support for applications of PSAs and risk informed decision making, particularly to support the design of NPPs and decision making during plant commissioning and operation. The revised Safety Guide's scope encompasses the main methodological aspects of PSA and in particular has been updated to reflect developments in specific areas, such as passive systems reliability, computer based systems reliability, combinations of hazards, human reliability analysis and to expand the scope of PSA to include site level risk considerations such as multi-unit and spent fuel pool PSA.

The objective of this Safety Guide is to provide recommendations for meeting the IAEA safety requirements in performing or managing a level 1 probabilistic safety assessment (PSA) project for a nuclear power plant. These recommendations promote technical consistency among level 1 PSA studies and support applications of PSA and risk informed decision making. The Safety Guide's scope encompasses all operational conditions of the plant and potential initiating events and hazards. Contents: 1. Introduction; 2. General considerations relating to the performance and use of PSA; 3. Project management.

The objective of this Safety Guide is to provide recommendations for meeting the IAEA safety requirements in performing or managing a level 2 probabilistic safety assessment (PSA) project for a nuclear power plant; thus it complements the Safety Guide on level 1 PSA. One of the aims of this Safety Guide is to promote a standard framework, standard terms and a standard set of documents for level 2 PSAs to facilitate regulatory and external peer review of their results. It describes all elements of the level 2 PSA that need to be carried out if the starting point is a fully comprehensive level 1.

The objective of this Safety Guide is to provide recommendations for meeting the IAEA safety requirements in performing or managing a level 2 probabilistic safety assessment (PSA) project for a nuclear power plant; thus it complements the Safety Guide on level 1 PSA. One of the aims of this Safety Guide is to promote a standard framework, standard terms and a standard set of documents for level 2 PSAs to facilitate regulatory and external peer review of their results. It describes all elements of the level 2 PSA that need to be carried out if the starting point is a fully comprehensive level 1 PSA. Contents: 1. Introduction; 2. PSA project management and organization; 3. Identification of design aspects important to severe accidents and acquisition of information; 4. Interface with level 1 PSA: Grouping of sequences; 5. Accident progression and containment analysis; 6. Source terms for severe accidents; 7. Documentation of the analysis: Presentation and interpretation of results; 8. Use and applications of the PSA; References; Annex I: Example of a typical schedule for a level 2 PSA; Annex II: Computer codes for simulation of severe accidents; Annex III: Sample outline of documentation for a level 2 PSA study.

The accident at the Fukushima Daiichi Nuclear Power Plant underlined the need to assess the nuclear safety of multi-unit sites considering the accident sequences involving more than one reactor units on site. The objective of this Safety Report is to provide a methodology for the development of a Multi-unit Probabilistic Safety Assessment (MUPSA). It provides practical examples and an overview of the actual state of practice in this area. The publication provides a detailed description of Level 1 MUPSA methodology, the principles of development of Level 2 MUPSA models and the path forward for multi-unit consequence analysis (Level 3 MUPSA). In addition, it summarizes the experience available in Member States in the area of MUPSA. The scope of this Safety Report includes consideration of various hazards and plant operational states normally considered in PSA development in the multi-unit context.

Probabilistic safety assessment (PSA) has contributed significantly to the understanding of how best to ensure the safety of nuclear power plants. By means of PSA, a nuclear power plant, including its safety systems and installations, can be analysed in its entirety. The rapid development of the method has resulted in its extensive use. This report reviews the general bases of PSA, emphasizing its merits and limits as well as the general lines of the future development of that methodology and its applications.