Technical Approach To Probabilistic Safety Assessment For Multiple Reactor Units

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.

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.

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

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.

Provides an approach for achieving the technical consistency of probabilistic safety assessments (PSAs) needed to support various PSA applications. The approach involves the consideration of a set of technical features, called attributes, of the major PSA elements relevant for various applications.

Presents a practical approach for incorporating human reliability analysis (HRA) into probabilistic safety assessment (PSA). This document describes the steps needed and the documentation that should be provided both to support the PSA itself and to ensure effective communication of important information arising from the studies.

In addition to presenting methodology, it shows how to identify accident vulnerability in the two industries. It reviews the causes of the two major nuclear accidents and many fatal accidents in the chemical industry, including Bhopal. Many examples of applications of PSA to both industries are presented."--BOOK JACKET. "Problems are included at the end of many chapters with answers at the back of the book."--Jacket.

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.