Probabilistic Safety Assessment Benchmarks of Multi-Unit, Multi-reactor Sites


Book Description

The Coordinated Research Project on Probabilistic Safety Assessment Benchmarks for Multiunit Multi Reactor Sites (2018-2022) brought together the experts from the IAEA Member States with mainly water-cooled reactor technologies to utilize, test and further develop their current or planned probabilistic safety assessments methods and assumptions by conducting and comparing results of meaningful multiunit multi reactor type probabilistic safety assessment (MUPSA) benchmark exercises. The objective was to share national expertise and participate in shared benchmark calculations. These calculations involved the development of MUPSA, based on single unit probabilistic safety assessments available in Member States. This publication is intended for nuclear engineers, researchers, code developers, experimentalists in nuclear energy fields, reactor vendors and developers, university professors and students, regulatory experts, and nuclear power plant planners.




Multi-unit Probabilistic Safety Assessment


Book Description

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.




Development and Application of Level 2 Probabilistic Safety Assessment for Nuclear Power Plants


Book Description

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.




Reliability and Probabilistic Safety Assessment in Multi-Unit Nuclear Power Plants


Book Description

Reliability and Probabilistic Safety Assessment in Multi-Unit Nuclear Power Plants presents the risk contributions from single and multi-unit Nuclear Power Plants to help aggregate the risks that may arise due to applicable hazards and operating states. The book combines the key features of multi-unit risk assessment in one resource, reviewing the practices adopted in various countries around the globe to exemplify the dependencies between units on a site. These dependencies include multi-unit interactions, environmental stresses, the sharing of systems, and the sharing of human resource in a control room, factors which can all introduce an increase potential for heightened accident conditions. This book helps readers systematically identify events and evaluate techniques of possible accident outcomes within multi-units. It serves as a ready reference for PSA analysts in identifying a suitable site and the sharing of resources, while carrying out multi-unit risk assessments to ensure the safety of the public and the environment. It will also be valuable for nuclear researchers, designers and regulators of nuclear power plants, nuclear regulatory agencies, PSA engineers and practicing safety professionals. - Provides a framework for nuclear and PSA researchers and professionals on the design and operation of multi-unit risk assessments - Reviews practices adopted in various regions around the globe to analyze dependencies between units - Includes modeling techniques of inter-connections and shared resources, as well as risk aggregation




Lessons Learned from the Fukushima Nuclear Accident for Improving Safety of U.S. Nuclear Plants


Book Description

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.




Basic Safety Principles for Nuclear Power Plants


Book Description

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.




Technical Approach to Probabilistic Safety Assessment for Multiple Reactor Units


Book Description

The technical approach described in this publication builds on the use of a single unit probabilistic safety assessment (PSA) and identifies considerations that are needed from the multi-unit perspective. This is the first attempt to expand the current PSA process to take account of multi-unit issues, and has been done by distilling lessons learned from the Fukushima Daiichi accident and other multi-unit events, and by reviewing previous PSAs and supporting research that have addressed the risks of multi-unit accidents. The publication provides a roadmap and methodology for performing a multi-unit PSA, proposes a set of site level risk metrics, and presents examples of approaches to resolve specific issues.




Safety of Nuclear Power Plants


Book Description

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.




Probabilistic Safety Assessment for Seismic Events


Book Description

Probabilistic safety assessment (PSA) is considered to be an important tool for assessing the safety of nuclear installations (typically used for safety assessment of nuclear power plants) in relation to potential initiating events that can be caused by random component failure and human error, as well as internal and external hazards. The purpose of seismic PSAs performed on nuclear installations is to provide risk insights related to their seismic robustness. The methodology for seismic safety evaluations includes a combination of deterministic and probabilistic approaches. Their applications typically address the impact of beyond design basis seismic events. This publication provides a detailed methodology for seismic PSA in line with the current international practices for seismic safety assessment of nuclear installations. Taking into account recommendations provided in IAEA safety standards and information reflected in internationally recognized technical standards, it reflects the current state of practice in the area of seismic PSA.




Thermal-Hydraulic Analysis of Nuclear Reactors


Book Description

This revised text covers the fundamentals of thermodynamics required to understand electrical power generation systems and the application of these principles to nuclear reactor power plant systems. The book begins with fundamental definitions of units and dimensions, thermodynamic variables and the Laws of Thermodynamics progressing to sections on specific applications of the Brayton and Rankine cycles for power generation and projected reactor systems design issues. It is not a traditional general thermodynamics text, per se, but a practical thermodynamics volume intended to explain the fundamentals and apply them to the challenges facing actual nuclear power plants systems, where thermal hydraulics comes to play. There have been significant new findings for intercooled systems since the previous edition published and they will be included in this volume. New technology plans for using a Nuclear Air-Brayton as a storage system for a low carbon grid are presented along with updated component sizes and performance criteria for Small Modular Reactors. Written in a lucid, straight-forward style while retaining scientific rigor, the content is accessible to upper division undergraduate students and aimed at practicing engineers in nuclear power facilities and engineering scientists and technicians in industry, academic research groups, and national laboratories. The book is also a valuable resource for students and faculty in various engineering programs concerned with nuclear reactors.