ISO 4917-3:2024

Overview

ISO 4917-3:2024 - Design of nuclear power plants against seismic events - Part 3: Civil structures specifies requirements for the seismic design and verification of civil structures in nuclear power plants with water-cooled reactors. The standard focuses on ensuring load-bearing capacity and serviceability (e.g., deformation and crack-width limits) during seismic events. It assumes the site geology and tectonics have been investigated and found suitable and excludes equipment cranes, lifting detachment devices, and component mounting supports.

Key topics and technical requirements

• Scope and applicability
  • Applies to buildings and structural members (reinforced/pre‑stressed concrete, steel, steel‑composite, masonry) including containment, platforms, crane runways and canals.
  • Independent of national codes; Annex A provides recommendations based on KTA and European standards.
• Seismic event definition and design philosophy
  • Aligned with the safety objectives in ISO 4917-1 and nuclear seismic protection principles (IAEA guidance referenced).
• Structure analysis and modeling
  • Requirements for geotechnical parameters, dynamic subsoil properties, material characteristics, effective stiffness, contributing masses and damping.
  • Treatment of hydrodynamic effects for fluid‑containing structures.
• Analysis methods
  • Permitted analysis approaches: response spectrum, time history, frequency‑domain and simplified methods, with guidelines for building response spectra and acceleration time‑history derivation.
• Soil–structure interaction
  • Kinematic and inertial interaction considerations, impedance functions and dynamic foundation behavior.
• Seismic verification concept
  • Ultimate Limit State (ULS) and Serviceability Limit State (SLS) verifications, load combinations, ductility concepts, equilibrium checks, deformation and crack controls.
  • Requirements for foundations and beyond‑design considerations.
• Structure‑type specific verifications
  • Verification approaches for reinforced/pre‑stressed concrete, steel structures, masonry, steel‑composite systems, fastening constructions, buried pipelines and support structures.

Practical applications and users

ISO 4917-3:2024 is intended for:

• Structural and seismic engineers designing nuclear civil structures
• Nuclear plant designers and engineering contractors
• Site evaluators and geotechnical engineers
• Regulatory authorities, licensing bodies and safety assessors
• Consultants preparing seismic verification reports and design documentation

Use cases include seismic design checks for containment buildings, foundation design accounting for soil–structure interaction, verification of deformation/crack limits for safety‑related functions, and development of time‑history or response‑spectrum analyses for licensing submittals.

Related standards

• ISO 4917-1:2024 - Principles (safety objectives and overarching requirements)
• ISO 4917-4:2024 - Components
• IAEA SSG-67 (Seismic Design for Nuclear Installations)
• Annex A (informative) - recommendations based on KTA and European standards

Keywords: ISO 4917-3:2024, seismic design, nuclear power plants, civil structures, seismic verification, soil‑structure interaction, response spectrum, time history.