ISO 4917-1:2024

Overview

ISO 4917-1:2024 - Design of nuclear power plants against seismic events - Part 1: Principles sets out the fundamental principles for seismic design of nuclear power plants with water-cooled reactors. It defines the safety objectives and the general framework for protecting people and the environment from radiation risks caused by earthquakes. The standard is intended for use where site geology and tectonics have been investigated and the site is considered suitable for a nuclear installation. Note: seismic isolation is not addressed in this series.

Key topics and requirements

• Safety objectives: ensuring control of reactivity, cooling of fuel assemblies, confinement of radioactive substances, and limiting radiation exposure.
• Design basis earthquake (DBE): definition and specification (DBE is equivalent to SL‑2 as per IAEA SSG-67 or some national safe‑shutdown earthquake (SSE) definitions).
• DBE determination methods: deterministic and probabilistic approaches (including probabilistic seismic hazard analysis / PSHA and use of ground motion prediction equations - GMPEs).
• Seismic-engineering parameters: response spectra, peak ground acceleration, strong motion duration and other parameters required for design input.
• Classification and verification: design basis classification of components and civil structures; verification of DBE safety for both structural and non‑structural elements.
• Combination of actions: rules for combining seismic loads with other loads and operational conditions.
• Analysis and modeling: requirements for modeling, modal combination (e.g., CQC), acceleration time histories and accepted analysis methods.
• Instrumentation, inspection and post‑seismic measures: seismic instrumentation, inspection level earthquakes, and actions after an event.
• Secondary effects and beyond‑design events: treatment of ground displacements, fault activity, and considerations for beyond‑design‑basis earthquakes.

Applications and users

ISO 4917-1:2024 is practical for:

• Nuclear design engineers and seismic engineers preparing plant and component designs.
• Structural and civil engineers assessing buildings and support structures at nuclear sites.
• Licensing authorities, regulators and safety assessors reviewing seismic aspects of nuclear plant design and operation.
• Site evaluators and geotechnical specialists performing seismic hazard and paleoseismology studies.
• Project managers and QA teams implementing verification, instrumentation and post‑event inspection programs.

Keywords: ISO 4917-1:2024, seismic design, nuclear power plants, design basis earthquake, DBE, PSHA, GMPE, water-cooled reactors, seismic instrumentation, safety objectives.

Related standards

• IAEA Safety Standards Series No. SSG-67, Seismic Design for Nuclear Installations (referenced normative guidance).
• IAEA safety requirements (e.g., SSR‑2/1) for protective measures against seismic events.
• Other parts of the ISO 4917 series (see ISO website for the complete list).