Preface 

This is the fourth edition of CSA N289.1, General requirements for seismic design and qualification of nuclear power plants. It supersedes the previous editions, published in 2018, 2008, and 1980. The major changes to this edition include the following: • methods of seismic qualification revised to include experience-based approach; • definitions updated for consistency with other CSA Standards; • Clause C.4.3.2.6 updated to align with EPRI 3002010665; • "a seismic event close to…the seismic design basis" clarified in Clause 6.5.6.1; • Clause 5.3.7 p) revised to reference CSA N290.20 and address the operating organization’s aging- related degradation measures to assess the possible impact on seismic behaviour/qualification of safety-related structures, systems, and components (SSCs) during their seismic evaluation; • new provisions added for addressing post-earthquake planning and response; • requirements for seismic qualification by similarity enhanced to ensure that the method is adequately addressed in the Standard to be consistent with its use by industry; and • guidelines for seismic qualification by similarity and earthquake experience-based methods clarified and expanded to document recognized, acceptable methodologies for seismic qualification and capability. This Standard acts as an introduction to the CSA N289 series of Standards and supplements the Standards in this series with seismic qualification concepts and methodologies. Methods for evaluation of the seismic capacity of NPP safety-related structures, systems, and components (SSCs) are also described. In addition, this Standard incorporates methods developed for demonstrating that NPP safety-related SSCs possess seismic capacity with low probability of exceedance. The CSA N289 series of Standards covers general requirements for seismic hazard evaluation, seismic design, qualification, evaluation, and testing and monitoring. This Standard is used in conjunction with the following CSA N289 series of Standards: • CSA N289.2, Ground motion determination for seismic qualification of nuclear power plants; • CSA N289.3, Design procedures for seismic qualification of nuclear power plants; • CSA N289.4, Testing procedures for seismic qualification of nuclear power plant structures, systems, and components; and • CSA N289.5, Seismic instrumentation requirements for nuclear power plants and nuclear facilities. Note: Automatic shutdown is not a seismic design requirement of the CSA N289 series of Standards; however, sufficient seismic monitoring instrumentation of high reliability, as specified in CSA N289.5, is needed to collect data in order to facilitate decision-making regarding continued safe operation. The data could also be used in conjunction with other indicators to trip a reactor. The CSA N289 series of Standards provides general requirements for safe response to earthquake ground motions by monitoring ground motions, quantifying effects, and initiating operator actions, and by requiring seismic qualification and design of nuclear safety-related SSCs. Concrete containment structures (covered in the CSA N287 series of Standards), safety-related structures (covered in CSA N291), pressure-retaining systems and components (covered in CSA N285), and other systems and components required to safely shut down, cool, contain, and monitor the plant following a major earthquake should be seismically qualified using the CSA N289 series of Standards. The seismic requirements of the National Building Code of Canada (NBC) may be used for those parts of NPPs that have no effect on nuclear safety, though the operating organization may elect to use the CSA N289 series of Standards in place of the NBC. The CSA N289 series of Standards generally imposes more stringent seismic design requirements than the NBC. The CSA N289 series of Standards specifies means for the seismic qualification of those NPP SSCs necessary for safe shutdown, fuel cooling, the containment of potential releases of radioactive material, and the monitoring and control of essential safety-related functions in the event of an earthquake. The nuclear facility operating organization may use the CSA N289 series of Standards to seismically qualify those parts of a nuclear facility required to prevent an unacceptable release of radioactive material to the environment in the event of an earthquake. The CSA N-Series Standards provide an interlinked set of requirements for the management of nuclear facilities and activities. CSA N286 provides overall direction to management to develop and implement sound management practices and controls, while the other CSA Group nuclear Standards provide technical requirements and guidance that support the management system. This Standard works in harmony with CSA N286 and does not duplicate the generic requirements of CSA N286; however, it might provide more specific direction for those requirements. Users of this Standard are reminded that the site selection, design, manufacture, construction, installation, commissioning, operation, and decommissioning of nuclear facilities in Canada are subject to the Nuclear Safety and Control Act and its Regulations. The Canadian Nuclear Safety Commission might impose additional requirements to those specified in this Standard. This Standard was prepared by the Subcommittee on General Requirements for Seismic Design and Qualification of CANDU Nuclear Power Plants, under the jurisdiction of the Technical Committee on Seismic Design for Nuclear Power Plants and the Strategic Steering Committee on Nuclear Standards, and has been formally approved by the Technical Committee. 

Scope 

1.1 General 

This Standard sets forth the general requirements for seismic design and qualification of nuclear power plants (NPPs). Note: This Standard also provides guidance for preparing a seismic qualification governance document (see Clause 5.3.7). 

1.2 Application 

This Standard applies to all structures, systems, and components (SSCs) of NPPs requiring seismic qualification based on nuclear safety considerations (see Annex A). This Standard may also be applied to other SSCs, as deemed appropriate by the operating organization or by the authority having jurisdiction (AHJ) such as the Canadian Nuclear Safety Commission (CNSC). 

1.3 Seismic hazard level for NPPs 

This Standard was developed for NPPs in regions of low to moderate seismic hazard, comparable to the levels near Canada’s existing NPPs. In regions of higher seismic hazard, the engineering required for reliable design under strong earthquake shaking is more complex, and is beyond the scope of this Standard. Therefore, while the provisions of this Standard can be applied to any NPP site, additional provisions can be required for high seismic hazard sites. 

1.4 Application to other nuclear facilities 

This Standard may be applied, as appropriate, to nuclear facilities under the jurisdiction of the Nuclear Safety and Control Act. 

1.5 Terminology 

In this Standard, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application. 1.6 Additional terminology In this Standard, "shall be considered" or "shall consider" means that the user evaluates the impact and documents any decisions.