IEC/IEEE 60980-344:2020

IEC/IEEE 60980-344 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
Nuclear facilities – Equipment important to safety – Seismic qualification

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IEC/IEEE 60980-344 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
Nuclear facilities – Equipment important to safety – Seismic qualification

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.120.10; 27.120.20 ISBN 978-2-8322-8482-7

– 2 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 11
4 Abbreviated terms . 19
5 General discussion of earthquake environment and equipment response. 20
5.1 General . 20
5.2 Earthquake environment . 20
5.3 Equipment on foundations . 20
5.4 Equipment on structures . 20
5.5 Interfaces and adverse interactions. 21
5.6 Simulating vibration induced by an earthquake . 21
5.6.1 General . 21
5.6.2 Response spectrum . 21
5.6.3 Time history . 22
5.6.4 PSD function . 22
5.7 Damping . 22
5.7.1 General . 22
5.7.2 Measurement of damping . 23
5.8 Application of damping . 23
5.8.1 General . 23
5.8.2 Application of damping in testing . 23
5.8.3 Application of damping in analysis . 24
6 Seismic qualification requirements . 24
6.1 General . 24
6.2 Specification of equipment to be qualified . 25
6.3 Specification of ageing condition . 25
6.4 Specification of seismic requirements . 25
6.5 Specification of acceptance criteria . 25
7 Seismic qualification approach . 26
7.1 Safety function . 26
7.2 Seismic qualification methods . 26
8 Ageing . 27
8.1 General . 27
8.2 Thermal ageing . 28
8.3 Radiation ageing . 28
8.4 Material degradation and corrosion . 28
8.5 Mechanical or electrical cycle ageing . 28
8.6 Vibration ageing . 28
8.6.1 General . 28
8.6.2 Ageing from non-seismic vibration conditions . 29
8.6.3 Hydrodynamic loads . 29
8.6.4 Seismic ageing (OBE/S1) . 29
9 Testing . 29
9.1 General . 29

 IEC/IEEE 2020
9.1.1 Test programme . 29
9.1.2 Mounting . 31
9.1.3 Monitoring . 31
9.1.4 Loading . 31
9.1.5 Refurbishment . 32
9.1.6 Exploratory tests . 32
9.1.7 Seismic ageing (OBE/S1) . 34
9.2 Proof and generic testing . 34
9.3 Fragility testing . 35
9.4 Component testing . 35
9.5 Assembly testing . 35
9.5.1 General . 35
9.6 Test methods . 36
9.6.1 General . 36
9.6.2 Single-frequency test . 37
9.6.3 Multiple-frequency tests . 40
9.6.4 Other tests . 45
9.6.5 Test duration and low-cycle fatigue potential . 45
9.6.6 Multi-axis tests . 45
9.6.7 Line-mounted equipment . 47
9.6.8 Additional tests . 48
9.7 Test documentation . 48
10 Qualification by similarity . 48
10.1 General . 48
10.2 Excitation . 48
10.3 Physical systems . 48
10.4 Safety function . 49
11 Analysis . 49
11.1 General . 49
11.2 Seismic analysis methods . 50
11.2.1 General . 50
11.2.2 Static analysis . 51
11.2.3 Static coefficient analysis . 51
11.2.4 Dynamic analysis . 51
11.3 Nonlinear equipment response . 52
11.4 Other dynamic loads . 52
11.5 Seismic analysis results . 52
11.6 Documentation of analysis . 53
12 Combined analysis and testing . 53
12.1 General . 53
12.2 Modal testing . 53
12.2.1 General . 53
12.2.2 Normal-mode method . 53
12.2.3 Transfer-function method . 54
12.2.4 Analytical methods utilizing test data . 54
12.2.5 Qualification . 54
12.3 Extrapolation for similar equipment . 54
12.3.1 General . 54
12.3.2 Test method . 54

– 4 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
12.3.3 Analysis . 55
12.4 Shock testing . 55
12.5 Extrapolation for multi-cabinet assemblies . 55
12.6 Other test/analysis . 55
13 Documentation . 56
13.1 General . 56
13.2 Seismic qualification report . 56
13.2.1 General . 56
13.2.2 Analysis . 56
13.2.3 Testing . 56
13.2.4 Combined analysis and testing or similarity . 57
Annex A (normative) Experience-based seismic qualification . 58
A.1 General . 58
A.2 Earthquake experience data . 58
A.2.1 General . 58
A.2.2 Characterization of the earthquake experience motions . 58
A.2.3 Earthquake experience spectrum (EES). 59
A.2.4 Characterization of reference equipment class . 59
A.2.5 Qualification of candidate equipment . 61
A.3 Test experience data . 62
A.3.1 General . 62
A.3.2 Characterization of test experience input motions . 62
A.3.3 Test experience spectra (TES) . 62
A.3.4 Characterization of reference equipment class . 63
A.3.5 Qualification of candidate equipment . 64
A.4 Special considerations . 64
A.4.1 Inherently rugged equipment . 64
A.4.2 Limitations . 65
A.5 Experience-based documentation . 65
A.5.1 General . 65
A.5.2 Reference data . 66
A.5.3 Candidate equipment qualification . 66
Annex B (informative) Measurement of zero period acceleration . 67
Annex C (informative) Frequency content and stationarity . 68
Annex D (informative) Fragility testing . 69
D.1 General . 69
D.2 Excitation motion . 69
D.3 Application of results. 70
D.4 Other considerations . 70
Annex E (informative) Test duration and number of cycles . 72
Annex F (informative) Statistically independent motions . 76
Annex G (informative) Seismic qualification illustrative flowcharts . 77
G.1 General . 77
G.2 Establishment of seismic conditions and acceptance criteria . 77
G.3 Qualification by testing . 77
G.4 Qualification by analysis . 77
G.5 Qualification by combination of analysis and testing . 77
Bibliography . 82

 IEC/IEEE 2020
Figure 1 – Sine beat . 39
Figure 2 – Decaying sine . 39
Figure 3 – Random spectrum with superimposed sine beats . 43
Figure 4 – Resonant amplification versus cycles per beat . 44
Figure E.1 – Fractional cycles to obtain one equipment maximum peak cycle . 73
Figure E.2 – Equivalent peak-stress cycles induced by stationary random motion . 74
Figure E.3 – Equivalent peak-stress cycles induced by stationary random motion to 20 Hz . 74
Figure G.1 – Seismic qualification flowchart . 78
Figure G.2 – Seismic qualification test flowchart . 79
Figure G.3 – Seismic qualification analysis flowchart . 80
Figure G.4 – Seismic qualification analysis and test flowchart . 81

Table A.1 – EES reduction factor based on number of independent items . 60

– 6 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR FACILITIES –
EQUIPMENT IMPORTANT TO SAFETY –
SEISMIC QUALIFICATION
FOREWORD
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 IEC/IEEE 2020
International Standard IEC/IEEE 60980-344 has been prepared by subcommittee 45A:
Instrumentation, control and electrical power systems of nuclear facilities, of IEC technical
committee 45: Nuclear instrumentation, in cooperation with Nuclear Power Engineering
Committee of the IEEE, under the IEC/IEEE Dual Logo Agreement.
It is published as an IEC/IEEE dual logo standard.
This new edition cancels and replaces the first edition of IEC 60980, published in 1989, and
TM
constitutes a technical revision. It also supersedes IEEE Std 344 -2013.
The text of this standard is based on the following IEC documents:
FDIS Report on voting
45A/1323/FDIS 45A/1334/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
International standards are drafted in accordance with the rules given in the ISO/IEC Directives,
Part 2.
The IEC Technical Committee and IEEE Technical Committee have decided that the contents
of this publication will remain unchanged until the stability date indicated on the IEC web site
under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
INTRODUCTION
a) Technical background, main issues and organisation of the Standard
This standard is applicable to electrical equipment important to safety and its interfaces that
are necessary to perform a safety function, or whose failure could adversely affect the safety
functions of other equipment.
Electrical equipment in nuclear facilities shall meet its safety function requirements throughout
its installed life. This is accomplished by a thorough programme of quality assurance, design
control, quality control, qualification, production, transportation, storage, installation,
maintenance, periodic testing, and surveillance. This IEC/IEEE standard specifically focuses
on seismic qualification. This standard shall be used in conjunction with IEC/IEEE 60780-323.
Other aspects, relating to quality assurance, reliability, selection and use of electronic devices,
design and modification of digital systems including Verification and Validation (V&V) activities
are not part of this standard.
Industry research in the area of equipment qualification and decades of its application have
greatly benefited this standard. Future activities of the working group to update this standard
will consider the following:
• Experience and knowledge gained by using condition monitoring techniques,
• Knowledge gained on ageing mechanisms and kinetics,
• Improvement in the use of methods (test and analysis) described throughout the standard,
• Improvement of computation tools and modalities of use.
It is intended that the Standard be used by operators of NPPs (utilities), systems evaluators,
equipment manufacturers, test facilities, qualification laboratories and by licensors.
b) Situation of the current standard in the structure of the IEC SC 45A standard series
IEC 61513 and IEC 63046 are first level IEC SC 45A documents that give guidance applicable
to Instrumentation and Control (I&C) system and electrical power systems (at system level).
They are completed by guidance relative to functional classification (IEC 61226).
These documents are supplemented by second level IEC SC 45A documents. Second level IEC
SC 45A documents give guidance on hardware design (IEC 60987), software (IEC 60880 and
IEC 62138), selection and use of HDL programmed integrated circuits (IEC 62566),
requirements in order to reduce the possibility and limit the impact of common cause failure of
category A functions (IEC 62340), qualification (IEC/IEEE 60780-323, IEC/IEEE 60980-344 and
IEC 62003), control room design (IEC 62342) and cybersecurity (IEC 62645).
IEC/IEEE 60980-344 is a second level IEC SC 45A document which focuses on seismic
qualification of electrical equipment important to safety.
For more details on the structure of the IEC SC 45A standard series, see item d) of this
introduction.
 IEC/IEEE 2020
c) Recommendations and limitations regarding the application of this standard
This dual logo standard applies to all electrical equipment important to safety in accordance
with IAEA terminology. If using IEEE standards, this standard applies to systems, structures,
and components classified as safety or safety-related. If using the IEC 61226 and IEC 61513
classification guidance, this standard applies to all Class 1, 2 and 3 equipment. This document
shall only be applied in accordance with the single selected classification scheme, either IEC
or IEEE.
To ensure that the Standard will continue to be relevant in future years, the emphasis has been
placed on issues of principle, rather than specific technologies.
d) Description of the structure of the IEC SC 45A standard series and relationships with
other IEC documents and other bodies documents (IAEA, ISO)
The top-level documents of the IEC SC 45A standard series are IEC 61513 and IEC 63046.
IEC 61513 provides general requirements for I&C systems and equipment that are used to
perform functions important to safety in NPPs. IEC 63046 provides general requirements for
electrical power systems of NPPs; it covers power supply systems including the supply systems
of the I&C systems. IEC 61513 and IEC 63046 are to be considered in conjunction and at the
same level. IEC 61513 and IEC 63046 structure the IEC SC 45A standard series and shape a
complete framework establishing general requirements for instrumentation, control and
electrical systems for nuclear power plants.
IEC 61513 and IEC 63046 refer directly to other IEC SC 45A standards for general topics
related to categorization of functions and classification of systems, qualification, separation,
defence against common cause failure, control room design, electromagnetic compatibility,
cybersecurity, software and hardware aspects for programmable digital systems, coordination
of safety and security requirements and management of ageing. The standards referenced
directly at this second level should be considered together with IEC 61513 and IEC 63046 as a
consistent document set.
At a third level, IEC SC 45A standards not directly referenced by IEC 61513 or by IEC 63046
are standards related to specific equipment, technical methods, or specific activities. Usually
these documents, which make reference to second-level documents for general topics, can be
used on their own.
A fourth level extending the IEC SC 45 standard series, corresponds to the Technical Reports
which are not normative.
The IEC SC 45A standards series consistently implements and details the safety and security
principles and basic aspects provided in the relevant IAEA safety standards and in the relevant
documents of the IAEA nuclear security series (NSS). In particular this includes the IAEA
requirements SSR-2/1, establishing safety requirements related to the design of nuclear power
plants (NPPs), the IAEA safety guide SSG-30 dealing with the safety classification of structures,
systems and components in NPPs, the IAEA safety guide SSG-39 dealing with the design of
instrumentation and control systems for NPPs, the IAEA safety guide SSG-34 dealing with the
design of electrical power systems for NPPs and the implementing guide NSS 17 for computer
security at nuclear facilities. The safety and security terminology and definitions used by
SC 45A standards are consistent with those used by the IAEA.

– 10 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
IEC 61513 and IEC 63046 have adopted a presentation format similar to the basic safety
publication IEC 61508 with an overall life-cycle framework and a system life-cycle framework.
Regarding nuclear safety, IEC 61513 and IEC 63046 provide the interpretation of the general
requirements of IEC 61508-1, IEC 61508-2 and IEC 61508-4, for the nuclear application sector.
In this framework IEC 60880, IEC 62138 and IEC 62566 correspond to IEC 61508-3 for the
nuclear application sector. IEC 61513 and IEC 63046 refer to ISO as well as to IAEA GS-R part
2 and IAEA GS-G-3.1 and IAEA GS-G-3.5 for topics related to quality assurance (QA). At level
2, regarding nuclear security, IEC 62645 is the entry document for the IEC/SC 45A security
standards. It builds upon the valid high level principles and main concepts of the generic
security standards, in particular ISO/IEC 27001 and ISO/IEC 27002; it adapts them and
completes them to fit the nuclear context and coordinates with the IEC 62443 series. At level
2, IEC 60964 is the entry document for the IEC/SC 45A control rooms standards and IEC 62342
is the entry document for the ageing management standards.
NOTE 1 It is assumed that for the design of I&C systems in NPPs that implement conventional safety functions (e.g.
to address worker safety, asset protection, chemical hazards, process energy hazards) international or national
standards would be applied.
NOTE 2 IEC/SC 45A domain was extended in 2013 to cover electrical systems. In 2014 and 2015 discussions were
held in IEC/SC 45A to decide how and where general requirements for the design of electrical systems were to be
considered. IEC/SC 45A experts recommended that an independent standard be developed at the same level as
IEC 61513 to establish general requirements for electrical systems. Project IEC 63046 is now launched to cover this
objective. When IEC 63046 is published, this Note 2 of the introduction of IEC/SC 45A standards will be suppressed.

 IEC/IEEE 2020
NUCLEAR FACILITIES –
EQUIPMENT IMPORTANT TO SAFETY –
SEISMIC QUALIFICATION
1 Scope
This International Standard describes methods for establishing seismic qualification procedures
that will yield quantitative data to demonstrate that the equipment can meet its performance
requirements. This document is applicable to electrical, mechanical, instrumentation and control
equipment/components that are used in nuclear facilities. This document provides methods and
documentation requirements for seismic qualification of equipment to verify the equipment’s
ability to perform its specified performance requirements during and/or after specified seismic
demands. This document does not specify seismic demand or performance requirements. Other
aspects, relating to quality assurance, selection of equipment, and design and modification of
systems, are not part of this document. As seismic qualification is only a part of equipment
qualification, this document is used in conjunction with IEC/IEEE 60780-323.
The seismic qualification demonstrates equipment’s ability to perform its safety function(s)
during and/or after the time it is subjected to the forces resulting from at least one safe shutdown
earthquake (SSE/S2). This ability is demonstrated by taking into account, prior to the SSE/S2,
the ageing of equipment and the postulated occurrences of a given number of lower intensity
operating basis earthquake (OBE/S1). Ageing phenomena to be considered, if specified in the
design specification, are those which could increase the vulnerability of equipment to vibrations
caused by an SSE/S2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-2-6, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC/IEEE 60780-323, Nuclear facilities – Electrical equipment important to safety –
1 2
Qualification ,
TM
IEEE Std 382 , IEEE Standard for Qualification of Safety-Related Actuators for Nuclear Power
Generating Stations
3 Terms and definitions
The terminology and definitions used in this document are consistent with IAEA Safety
Glossary .
____________
IEEE publications are available from The Institute of Electrical and Electronics Engineers
(http://standards.ieee.org/).
The IEEE standards or products referred to in this clause are trademarks of The Institute of Electrical and
Electronics Engineers, Inc.
IAEA safety glossary is available at https://www.iaea.org/publications/11098/iaea-safety-glossary-2018-edition

– 12 – IEC/IEEE 60980-344:2020
 IEC/IEEE 2020
For the purposes of this document, the following terms and definitions apply.
ISO, IEC, and IEEE maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEEE Standards Dictionary Online: available at http://dictionary.ieee.org
The IEEE Standards Dictionary Online should be consulted for terms not defined in these
databases.
3.1
acceptance criteria
specified bounds on the value of a functional indicator or condition indicator used to assess the
ability of a structure, system or component to perform its design function
Note 1 to entry: Value(s) of performance parameters and other criteria to demonstrate that equipment can perform
the safety function(s) shall be identified.
[SOURCE: IAEA Safety Glossary, 2018]
3.2
assembly
comprising all electrical, mechanical, and structural components of the equipment including a
common mounting and supporting structure
3.3
broadband response spectrum
response spectrum that describes motion in which amplified response occurs over a wide
(broad) range of frequencies
3.4
Class 1E
safety classification of the electric equipment and systems that are essential to emergency
reactor shutdown, containment isolation, reactor core cooling, and containment and reactor
heat removal, or otherwise are essential in preventing significant release of radioactive material
to the environment
Note 1 to entry: Users of this standard are advised that “Class 1E” is a functional term. Equipment and systems are
to be classified Class 1E only if they fulfill the functions listed in the definition. Identification of systems or equipment
as Class 1E based on anything other than their function is an improper use of the term and should be avoided.
[SOURCE: IEEE Standards Dictionary Online]
3.5
components
one of the parts that make up an equipment. A component may be a hardware component (e.g.,
wires, transistors, integrated circuits, motors, relays, solenoids, pipes, fittings, pumps, tanks
and valve or a software component). A component may be made up of other components
Note 1 to entry: Components are items from which equipment is assembled.
Note 2 to entry: The terms component and device are interchangeable.
[SOURCE: IAEA Safety Glossary, 2018]
____________
IEEE Standards Dictionary Online subscription is available at: http://dictionary.ieee.org

 IEC/IEEE 2020
3.6
coherence function
comparative relationship between two time histories as a function of frequency
Note 1 to entry: It provides a statistical estimate of how much two motions are related, as a function of frequency.
Note 2 to entry: The numerical range is from zero for unrelated to +1,0 for related motions.
3.7
correlation coefficient function
comparative relationship between two time histories, as a function of time delay
Note 1 to entry: It provides a statistical estimate of how much two motions are related, as a function of time delay.
Note 2 to entry: The numerical range is from −1,0 for inversely related motions, zero for unrelated, to +1,0 for
related motions.
3.8
critical damping
least amount of viscous damping that causes a single-degree-of-freedom (SDOF) system to
return to its original position without oscillation after initial disturbance
[SOURCE: IEEE Standards Dictionary Online]
3.9
critical seismic characteristics
design, material, and performance char
...