An Overview Of Seismic Risk Analysis For Nuclear Power Plants

A systematic and comprehensive introduction of seismic risk analysis of critical engineering structures, focusing on nuclear power plants.

The development of protective measures to guard against the spread of radioactive debris following reactor disasters has been given extensive and careful engineering attention over the past several years. Much of this attention has been devoted to eliminating or minimizing the effects of malfunctions of internal components. But reactors can also suffer externally caused disasters—for example, their radioactive cores can be damaged by earthquakes or by missiles generated by tornadoes. Earthquakes in particular will continue to render man vulnerable even to the "peaceful atom" as the number of nuclear power plants increases and as they come to be located in those parts of the world that have a history of seismic activity. It was to consider such problems that the seminar reported here was held. The conferees, who are leaders in this special and important field, gathered in Cambridge, Massachusetts, in spring 1969, to present the papers whose titles are listed below. Together they cover both the theoretical underpinnings of the subject and specific applications to nuclear reactors; they provide both useful summaries of what is known to date and some new thinking on the subject, not before published. Contents: Preface—T. J. Thompson. Foreword—R. J. Hansen. Introduction—R. V. Whitman. Geological and Seismological Factors Influencing the Assessment of a Seismic Threat to Nuclear Reactors—Daniel Linehan, S. J. Geophysics—Keiiti Aki. Design Seismic Inputs—C. Allin Cornell. Some Observations on Probabilistic Methods in the Seismic Design of Nuclear Power Plants—C. Allin Cornell. Seismic Risk and Seismic Design Decisions—Luis Esteva. Fundamentals of Soil Amplification—J. M. Roesset. Soil Structure Interaction—R. V. Whitman. Evaluation of Soil Properties for Site Evaluation and Dynamic Analysis of Nuclear Plants—R. V. Whitman. Structural Response to Seismic Input—J. M. Biggs. Seismic Analysis of Equipment Mounted on a Massive Structure—J. M. Biggs and J. M. Roesset. Modal Response of Containment Structures—Peter Jan Pahl. Provision of Required Seismic Resistance—M. J. Holley, Jr. A Measure of Earthquake Intensity—Arturo Arias. Closure—R. J. Hansen.

This Safety Guide provides guidelines and recommends procedures for the evaluation of seismic hazards for nuclear power plants. Specifically, it provides recommendations on how to determine the ground motion hazards for a plant at a particular site and the potential for surface faulting, which could affect the feasibility of construction and safe operation of a plant at that site. The Guide supersedes IAEA Safety Series No. 50-SG-S1 (Rev.l), Earthquakes and Associated Topics in Relation to Nuclear Power plant Siting that was issued in 1991.

Experience shows that an assessment of the seismic capacity of an existing operating facility can be required for a number of reasons, for example identification of potential seismic vulnerabilities based on operating experience events or the periodic safety review programme. This publication covers the seismic safety evaluation programmes to be performed on existing nuclear installations in order to ensure that the required fundamental safety functions are available, with particular attention to the safe shutdown of reactors. It includes lessons learned based on the IAEA Action Plan on Nuclear Safety following the Fukushima Daiichi accident, and updated methodologies for seismic safety evaluation of nuclear installations.

This Safety Guide provides recommendations on a generally accepted way to design a nuclear power plant so that an earthquake motion at the site will not jeopardize the safety of the plant. It also gives guidance on a consistent application of methods and procedures for analysis, testing and qualification of structures and equipment so that they meet the safety requirements covering the design of nuclear power plants, safety assessments for the design and the regulatory issues concerned with the licensing of plants.

This book covers seismic probabilistic risk assessment (S-PRA) and related studies which have become more important to increase the safety of nuclear facilities against earthquakes and tsunamis in the face of the many uncertainties after the Fukushima accident. The topics are (1) Active faults and active tectonics important for seismic hazard assessment of nuclear facilities,(2) Seismic source modeling and simulation and modeling techniques indispensable for strong ground motion prediction, and (3) PRA with external hazard and risk communication. The Fukushima accident has showed us the limitations of the deterministic evaluation approach to external events (an earthquake and tsunami) in which there are many uncertainties. Furthermore, public anxiety regarding nuclear safety because of an unexpected threat caused by an earthquake or tsunami is growing. The current policy on the estimation of the design basis of ground motion as well as tsunami height still has not been improved following the Fukushima accident. In particular, the risk concept in a nuclear system regarding seismic motion and a tsunami beyond the design basis is indispensable. Therefore, research and development for PRA enhancing nuclear safety are being actively pursued not only in Japan but also worldwide. This book provides an opportunity for readers to consider the future direction of nuclear safety vis-à-vis natural disasters.