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.

On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.

The present publication can support PSA practitioners in appropriate planning of a PSA project taking into account possible uses of the PSA in the future. It can also be used by reviewers as an aid in assessing the quality of PSAs and judging the adequacy of a PSA for particular applications.

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 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 present report is a revision of Safety Series No. 75-INSAG-3 (1988), updating the statements made on the objectives and principles of safe design and operation for electricity generating nuclear power plants. It includes the improvements made in the safety of operating nuclear power plants and identifies the principles underlying the best current safety policies to be applied in future plants. It presents INSAG's understanding of the principles underlying the best current safety policies and practices of the nuclear power industry.

The March 11, 2011, Great East Japan Earthquake and tsunami sparked a humanitarian disaster in northeastern Japan. They were responsible for more than 15,900 deaths and 2,600 missing persons as well as physical infrastructure damages exceeding $200 billion. The earthquake and tsunami also initiated a severe nuclear accident at the Fukushima Daiichi Nuclear Power Station. Three of the six reactors at the plant sustained severe core damage and released hydrogen and radioactive materials. Explosion of the released hydrogen damaged three reactor buildings and impeded onsite emergency response efforts. The accident prompted widespread evacuations of local populations, large economic losses, and the eventual shutdown of all nuclear power plants in Japan. "Lessons Learned from the Fukushima Nuclear Accident for Improving Safety and Security of U.S. Nuclear Plants" is a study of the Fukushima Daiichi accident. This report examines the causes of the crisis, the performance of safety systems at the plant, and the responses of its operators following the earthquake and tsunami. The report then considers the lessons that can be learned and their implications for U.S. safety and storage of spent nuclear fuel and high-level waste, commercial nuclear reactor safety and security regulations, and design improvements. "Lessons Learned" makes recommendations to improve plant systems, resources, and operator training to enable effective ad hoc responses to severe accidents. This report's recommendations to incorporate modern risk concepts into safety regulations and improve the nuclear safety culture will help the industry prepare for events that could challenge the design of plant structures and lead to a loss of critical safety functions. In providing a broad-scope, high-level examination of the accident, "Lessons Learned" is meant to complement earlier evaluations by industry and regulators. This in-depth review will be an essential resource for the nuclear power industry, policy makers, and anyone interested in the state of U.S. preparedness and response in the face of crisis situations.

The limitation of 235U enrichment is a current concern among IAEA Member States. In response, work has been undertaken to provide a platform to facilitate a comprehensive review of the current status, prospects and challenges associated with the use of fuels having enrichments higher than 5 % 235U in light water reactors. This publication is the outcome of two technical meetings and compiles the results and conclusions in terms of benefits to be obtained from the use of high assay low enriched uranium (HALEU) fuel, with due consideration of safety issues that arise from its use. It details technological options and corresponding issues regarding fuel and core design, safety analysis and assessments relevant to manufacturing, handling, transportation, storage, irradiation, and performance in normal and accident conditions.

The aim of this book is to summarize probabilistic safety assessment (PSA) of nuclear power plants with WWER440 reactors and demonstrate that the plants are safe enough for producing energy even in light of the Fukushima accident. The book examines level 1 and 2 full power, low power and shutdown PSA, and summarizes the author’s experience gained during the last 35 years in this area. It provides useful examples taken from PSA training courses the author has lectured and organized by the International Atomic Energy Agency. Such training courses were organised in Argonne National Laboratory (Chicago, IL, USA), Abdus Salaam International Centre for Theoretical Physics (Trieste, Italy), Malaysia, Vietnam and Jordan to support experts from developing countries. The role of PSA for the plants is an estimation of the risks in absolute terms and in comparison with other risks of the technical and the natural world. Plant-specific PSAs are being prepared for the plants and being applied for detection of weaknesses, design improvement and backfitting, incident analysis, accident management, emergency preparedness, prioritization of research and development and to support the regulatory activities. There are three levels of PSA, being performed for full power and low power operation and shutdown operating modes of the plants: level 1, 2 and 3 PSA. The nuclear regulatory authorities do not require the level 3 PSA for the plants in the member countries of the European Union. This means that only a limited number of NPPs in Europe have the level 3 PSA available. However, in the light of the Fukushima accident the performance of such analyses is strongly recommended in the future. This book is intended for professionals working in the nuclear industry, researchers and students interested in safety of operational plants.