IEC/IEEE 60980-344:2020

Overview

IEC/IEEE 60980-344:2020 - "Nuclear facilities - Equipment important to safety - Seismic qualification" describes accepted methods for demonstrating that equipment in nuclear facilities can meet required safety performance when subjected to seismic events. The standard applies to electrical, mechanical, instrumentation and control equipment/components and provides methods for seismic qualification using testing, analysis, or combined approaches. It focuses on producing quantitative data to verify equipment performance during and/or after seismic demands (including consideration of prior ageing and lower-intensity earthquakes). NOTE: the document does not prescribe seismic demand spectra or specific performance limits - users must pair it with project-specific seismic requirements.

Key Topics and Requirements

• Scope of applicability: Equipment important to safety in nuclear power plants and related facilities (electrical, mechanical, I&C).
• Seismic qualification methods: Proof testing, generic testing, fragility testing, component and assembly testing, analysis (static, dynamic, nonlinear), and combined test/analysis approaches.
• Earthquake input modelling: Response spectrum, time history, and power spectral density (PSD) methods; guidance on multi-axis and multi-frequency testing.
• Ageing considerations: Thermal, radiation, corrosion/material degradation, mechanical/electrical cycling, vibration ageing, and effects of prior Operating Basis Earthquake (OBE/S1) before a Safe Shutdown Earthquake (SSE/S2).
• Damping and dynamic response: Measurement and application of damping in testing and analysis; modal testing and transfer-function methods.
• Qualification by similarity and extrapolation: Criteria and limits for using representative test data for similar equipment classes.
• Documentation and reporting: Seismic qualification reports, test plans, monitoring records and analysis documentation required to demonstrate conformance.
• Supportive guidance: Experience-based methods and annexes on fragility testing, zero period acceleration measurements, frequency content, and stationarity.

Practical Applications and Who Uses It

• Nuclear plant designers and system engineers establishing seismic qualification programs.
• Seismic qualification engineers and test laboratories performing vibration/shock testing and dynamic analysis.
• Equipment manufacturers and suppliers demonstrating equipment important to safety meets seismic performance expectations.
• Regulatory bodies and QA teams reviewing qualification evidence for licensing and compliance.
• Procurement and maintenance teams specifying qualification criteria, ageing conditions, and acceptance criteria for long-term plant operation.

This standard is essential when developing a robust seismic qualification strategy for safety-related equipment in nuclear facilities, ensuring traceable, quantitative verification of equipment capability under seismic demands.

Related Standards

• IEC/IEEE 60780-323 (used in conjunction with 60980-344 for overall equipment qualification)
• Relevant national seismic design and nuclear regulatory guides (project-specific seismic demands and performance criteria)