Seismic Design for Nuclear Installations

Specific Safety Guide

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• Publisher: International Atomic Energy Agency
• Year: 2021
• eBook ISBN: 9789201177216
• Topic: Technology & Engineering
• Subtopic: Mechanical Engineering
• Index: Technology & Engineering

This Safety Guide provides recommendations on how to meet the applicable safety requirements in relation to the design aspects of new nuclear installations subjected to seismic hazard. These recommendations focus on the consistent application of methods and procedures, in accordance with best practice, for seismic analysis, design, testing and qualification of structures, systems and components. New recommendations include applications of seismic isolation systems, the seismic margin to be achieved by the design and application of the graded approach. This Safety Guide is intended for use by organizations involved in the seismic design of nuclear installations, in analysis, verification and review, and in the provision of technical support, as well as by regulatory bodies.

1. INTRODUCTION

Background

1.1. IAEA Safety Standards Series No. SSR-2/1 (Rev. 1), Safety of Nuclear Power Plants: Design [1], establishes design requirements for the structures, systems and components (SSCs) of a nuclear power plant. Requirements for the design of research reactors and of nuclear fuel cycle facilities are established in IAEA Safety Standards Series No. SSR-3, Safety of Research Reactors [2], and IAEA Safety Standards Series No. SSR-4, Safety of Nuclear Fuel Cycle Facilities [3], respectively. These publications include requirements for the design to take into account external events, including earthquakes. This Safety Guide provides specific recommendations on the design of nuclear installations to cope with the effects generated by earthquakes.

1.2. This Safety Guide incorporates the following:

(a) Progress in the design of nuclear installations and in related research, as well as regulatory practices in States, considering the lessons identified from recent strong earthquakes that have affected nuclear installations;

(b) Recent developments in regulatory practices on application of risk informed and performance based approaches for assessing the safety of nuclear installations;

(c) The experience and results from seismic design for new nuclear installations in States;

(d) A more coordinated treatment of the design of nuclear installations against seismically induced geological and geotechnical hazards and concomitant events.

1.3. This Safety Guide provides a clear distinction between (a) the process for assessing the seismic hazards at a specific site and (b) the process for defining the related basis for design and evaluation of the nuclear installations. These processes correspond to (and are performed at) different stages in the lifetime of a nuclear installation. This Safety Guide addresses the interface between these processes so as to bridge any gaps between them and avoid undue overlapping of recommendations.

1.4. Recommendations on the process for assessing the seismic hazards at a specific site, including the definition of the parameters resulting from such an assessment, are provided in IAEA Safety Standards Series No. SSG-9 (Rev. 1), Seismic Hazards in Site Evaluation for Nuclear Installations [4].

1.5. There is an important difference between the seismic design and the seismic safety evaluation of nuclear installations. Seismic design and qualification of SSCs is most often performed at the design stage of the installation, prior to its construction. Seismic safety evaluation can be conducted at the design stage (using data corresponding to the detailed design) and after the installation has been constructed (using as-built and as-operating conditions). There are some exceptions, such as the seismic design of new or replacement components after construction of the installation. Recommendations on the evaluation of existing nuclear installations are provided in IAEA Safety Standards Series No. NS-G-2.13, Evaluation of Seismic Safety for Existing Nuclear Installations [5].

1.6. In several States, designs of new nuclear reactors are being developed generically to meet the needs of many sites across a large geographical area. The intent is that each generic design uses design bases that envelop the potential seismic hazard challenges at all the candidate sites. Confirmation of this is needed when a generic design is nominated for a particular site. At this point, the site specific seismic hazards need to be assessed and compared with the generic seismic hazard design bases to ensure there is an acceptable enveloping margin between them.

1.7. This Safety Guide supersedes IAEA Safety Standards Series No. NS-G-1.6, Seismic Design and Qualification for Nuclear Power Plants1.

Objective

1.8. The objective of this Safety Guide is to provide recommendations on how to meet the safety requirements established in SSR-2/1 (Rev. 1) [1], SSR-3 [2...

Table of contents

• 1. INTRODUCTION
• REFERENCES
• DEFINITIONS
• CONTRIBUTORS TO DRAFTING AND REVIEW