This publication summarizes the findings and conclusions of an IAEA coordinated research project (CRP) on fuel modelling in accident conditions, which was initiated under the IAEA Action Plan on Nuclear Safety following the Fukushima accident. The overall aim of the project was to analyse and better understand fuel behavior in accident conditions, with a focus on loss of coolant accidents. In the course of the project the participants used a mixture of data derived from accident simulation experiments, in particular data designed to investigate the fuel behaviour during design basis accident and design extension conditions. They carried out calculations on priority cases selected from a matrix of cases identified at the first research coordination meeting and designed to support their individual priorities. These priority cases were chosen as the best available to help determine which of the many models used in the codes best reflect reality. The CRP provided an ideal platform to compare their code results with others and especially with experimental data, to which they otherwise would not have had access. The achievements made within this CRP fostered new collaborations and enhanced the development and improvement of common models and highlighted differences in the interpretation of some experiments and therefore in the use of the codes ? the so-called user effects.

This publication is the result of an IAEA technical meeting and reports on Member States' capabilities in modelling, predicting and improving their understanding of the behaviour of nuclear fuel under accident conditions. The main results and outcomes of a coordinated research project (CRP) on this topic are also presented.

There is high interest in new fuel types with increased accident tolerance. These range from using an oxidation resistant coating on zirconium based cladding to alternate fuel and cladding materials. These new fuels/claddings under development must be licensed before being deployed industrially and therefore research is being undertaken to assess their behaviour in various conditions. This publication arises from an IAEA coordinated research project (CRP) dealing with the acquisition of data through experiments on new fuel types and cladding materials and the development of modelling capacity to predict the behaviour of the components and the integral performance of accident tolerant fuel designs under normal and transient conditions. Demonstrations of improvements under severe accident conditions were documented. Several coated cladding materials were produced, tested, characterized and analysed in round robin tests carried out within the CRP. For improvement and validation of fuel performance codes, several benchmarks were organized to compare and analyse predictions of the extended codes. The findings and conclusions of the CRP are summarized in this publication.

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.

Normal Accidents analyzes the social side of technological risk. Charles Perrow argues that the conventional engineering approach to ensuring safety--building in more warnings and safeguards--fails because systems complexity makes failures inevitable. He asserts that typical precautions, by adding to complexity, may help create new categories of accidents. (At Chernobyl, tests of a new safety system helped produce the meltdown and subsequent fire.) By recognizing two dimensions of risk--complex versus linear interactions, and tight versus loose coupling--this book provides a powerful framework for analyzing risks and the organizations that insist we run them. The first edition fulfilled one reviewer's prediction that it "may mark the beginning of accident research." In the new afterword to this edition Perrow reviews the extensive work on the major accidents of the last fifteen years, including Bhopal, Chernobyl, and the Challenger disaster. The new postscript probes what the author considers to be the "quintessential 'Normal Accident'" of our time: the Y2K computer problem.

This book captures the principles of safety evaluation as practiced in the regulated light-water reactor nuclear industry, as established and stabilized over the last 30 years. It is expected to serve both the current industry and those planning for the future. The work's coverage of the subject matter is the broadest to date, including not only the common topics of modeling and simulation, but also methods supporting the basis for the underlying assumptions, the extension to radiological safety, what to expect in a licensing review, historical perspectives and the implication for new designs.This text is an essential resource for practitioners and students, on the current best-practices in nuclear power plant safety and their basis. Contributors of this work are subject matter experts in their specialties, much of which was nurtured and inspired by Prof. Larry Hochreiter, a prominent nuclear safety pioneer.Related Link(s)

This publication is a revision by amendment of IAEA Safety Standards Series No. SSG-15 and provides recommendations and guidance on the storage of spent nuclear fuel. It covers all types of storage facility and all types of spent fuel from nuclear power plants and research reactors. It takes into consideration the longer storage periods beyond the original design lifetime of the storage facility that have become necessary owing to delays in the development of disposal facilities and the reduction in reprocessing activities. It also considers developments associated with nuclear fuel, such as higher enrichment, mixed oxide fuels and higher burnup. Guidance is provided on all stages in the lifetime of a spent fuel storage facility, from planning through siting and design to operation and decommissioning. The revision was undertaken by amending, adding and/or deleting specific paragraphs addressing recommendations and findings from studying the accident at the Fukushima Daiichi nuclear power plant in Japan.

Human error is implicated in nearly all aviation accidents, yet most investigation and prevention programs are not designed around any theoretical framework of human error. Appropriate for all levels of expertise, the book provides the knowledge and tools required to conduct a human error analysis of accidents, regardless of operational setting (i.e. military, commercial, or general aviation). The book contains a complete description of the Human Factors Analysis and Classification System (HFACS), which incorporates James Reason's model of latent and active failures as a foundation. Widely disseminated among military and civilian organizations, HFACS encompasses all aspects of human error, including the conditions of operators and elements of supervisory and organizational failure. It attracts a very broad readership. Specifically, the book serves as the main textbook for a course in aviation accident investigation taught by one of the authors at the University of Illinois. This book will also be used in courses designed for military safety officers and flight surgeons in the U.S. Navy, Army and the Canadian Defense Force, who currently utilize the HFACS system during aviation accident investigations. Additionally, the book has been incorporated into the popular workshop on accident analysis and prevention provided by the authors at several professional conferences world-wide. The book is also targeted for students attending Embry-Riddle Aeronautical University which has satellite campuses throughout the world and offers a course in human factors accident investigation for many of its majors. In addition, the book will be incorporated into courses offered by Transportation Safety International and the Southern California Safety Institute. Finally, this book serves as an excellent reference guide for many safety professionals and investigators already in the field.

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.