SIST EN 60780-323:2017

SLOVENSKI STANDARD
01-december-2017
-HGUVNLREMHNWL(OHNWULþQDRSUHPDSRPHPEQD]DYDUQRVW.YDOLILNDFLMD,(&,(((

Nuclear facilities - Electrical equipment important to safety - Qualification (IEC/IEEE
60780-323:2016)
Kerntechnische Anlagen - Elektrisches Gerät mit sicherheitstechnischer Bedeutung -
Qualifizierung (IEC/IEEE 60780-323:2016)
Installations nucléaires - Equipements électriques importants pour la sûreté -
Qualification (IEC/IEEE 60780-323:2016)
Ta slovenski standard je istoveten z: EN 60780-323:2017
ICS:
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 60780-323

NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2017
ICS 27.120.20
English Version
Nuclear facilities - Electrical equipment important to safety -
Qualification
(IEC/IEEE 60780-323:2016)
Installations nucléaires - Equipements électriques Kerntechnische Anlagen - Elektrisches Gerät mit
importants pour la sûreté - Qualification sicherheitstechnischer Bedeutung - Qualifizierung
(IEC/IEEE 60780-323:2016) (IEC/IEEE 60780-323:2016)
This European Standard was approved by CENELEC on 2017-09-11. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60780-323:2017 E
European foreword
This document (EN 60780-323:2017) consists of the text of IEC/IEEE 60780-323:2016 prepared by
SC 45A "Instrumentation, control and electrical systems of nuclear facilities" of IEC/TC 45 "Nuclear
instrumentation", in cooperation with the Nuclear Power Engineering Committee of the Power and
Energy Society of the IEEE, under the IEC/IEEE Dual Logo Agreement between IEC and IEEE.

The following dates are fixed:

• latest date by which this document has to be (dop) 2018-09-11
implemented at national level by publication of an
identical national standard or by endorsement
• latest date by which the national standards (dow) 2020-09-11
conflicting with this document have to be
withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

As stated in the nuclear safety directive 2009/71/EURATOM, Chapter 1, Article 2, item 2, Member
States are not prevented from taking more stringent safety measures in the subject-matter covered by
the Directive, in compliance with Community law. In a similar manner, this European standard does
not prevent Member States from taking more stringent nuclear safety and/or security measures in the
subject-matter covered by this standard.
Endorsement notice
The text of the International Standard IEC/IEEE 60780-323:2016 was approved by CENELEC as a
European Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60068-2-6 NOTE Harmonized as EN 60068-2-6.
IEC 60068-2-11 NOTE Harmonized as EN 60068-2-11.
IEC 60068-2-14 NOTE Harmonized as EN 60068-2-14.
IEC 60068-2-27 NOTE Harmonized as EN 60068-2-27.
IEC 60068-2-30 NOTE Harmonized as EN 60068-2-30.
IEC 60068-2-57 NOTE Harmonized as EN 60068-2-57.
IEC 60068-3-3 NOTE Harmonized as EN 60068-3-3.
IEC 60216-1 NOTE Harmonized as EN 60216-1.
IEC 60216-2 NOTE Harmonized as EN 60216-2.
IEC 60529 NOTE Harmonized as EN 60529.
IEC 60544-2 NOTE Harmonized as EN 60544-2.
IEC 60811-412 NOTE Harmonized as EN 60811-412.
IEC 61000-4 Series NOTE Harmonized as EN 61000-4 Series.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year

IEC 60980 -  Recommended practices for seismic - -
qualification of electrical equipment of the
safety system for nuclear generating
stations
TM
IEEE Std 344 2013 IEEE Standard for Seismic Qualification of - -
Equipment for Nuclear Power Generating
Stations
IEC/IEEE 60780-323 ®
Edition 1.0 2016-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear facilities – Electrical equipment important to safety – Qualification

Installations nucléaires – Equipements électriques importants pour la sûreté –

Qualification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-3168-5

– 2 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope and object . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Symbols and abbreviations . 12
5 Principles of equipment qualification . 12
5.1 Qualification objective . 12
5.2 Qualified life and qualified condition . 13
5.3 Qualification elements . 13
5.4 Qualification documentation . 13
6 Qualification methods . 14
6.1 Initial qualification . 14
6.1.1 Type testing . 14
6.1.2 Operating experience . 14
6.1.3 Analysis . 14
6.1.4 Combined methods . 14
6.2 Reassessing qualified life . 14
6.2.1 General . 14
6.2.2 Method 1: Using conservatism . 15
6.2.3 Method 2: Type test on aged samples from the plant . 15
6.2.4 Method 3: Performing type test for longer qualified life . 15
6.2.5 Method 4: Component replacement . 15
6.3 Condition monitoring . 15
7 Qualification program . 16
7.1 General . 16
7.2 Equipment specification. 16
7.2.1 General . 16
7.2.2 Equipment identification . 16
7.2.3 Interfaces . 16
7.2.4 Qualified life objective . 17
7.2.5 Safety function(s) . 17
7.2.6 Service conditions . 17
7.3 Qualification programme plan . 18
7.3.1 General . 18
7.3.2 Ageing . 18
7.3.3 Significant ageing mechanisms . 18
7.3.4 Qualified life objective . 19
7.3.5 Service condition margin . 19
7.3.6 Maintenance . 19
7.3.7 Acceptance criteria . 19
7.4 Qualification programme implementation . 19
7.4.1 Type testing . 19
7.4.2 Operating experience . 25
7.4.3 Qualification with analysis . 26

IEC/IEEE 60780-323:2016 – 3 –
© IEC/IEEE 2016
7.4.4 Modifications. 27
8 Documentation . 27
8.1 General . 27
8.2 General documentation requirements . 27
8.3 Specific documentation requirements for mild environment . 28
8.4 Specific documentation requirements for harsh environment . 28
Bibliography . 29

Table 1 – Minimal test margins recommended for DBEs . 21

– 4 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
NUCLEAR FACILITIES – ELECTRICAL EQUIPMENT
IMPORTANT TO SAFETY – QUALIFICATION

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation.
IEEE Standards documents are developed within IEEE Societies and Standards Coordinating Committees of the
IEEE Standards Association (IEEE-SA) Standards Board. IEEE develops its standards through a consensus
development process, approved by the American National Standards Institute, which brings together volunteers
representing varied viewpoints and interests to achieve the final product. Volunteers are not necessarily
members of IEEE and serve without compensation. While IEEE administers the process and establishes rules
to promote fairness in the consensus development process, IEEE does not independently evaluate, test, or
verify the accuracy of any of the information contained in its standards. Use of IEEE Standards documents is
wholly voluntary. IEEE documents are made available for use subject to important notices and legal disclaimers
(see http://standards.ieee.org/IPR/disclaimers.html for more information).
IEC collaborates closely with IEEE in accordance with conditions determined by agreement between the two
organizations. This Dual Logo International Standard was jointly developed by the IEC and IEEE under the
terms of that agreement.
2) The formal decisions of IEC on technical matters express, as nearly as possible, an international consensus of
opinion on the relevant subjects since each technical committee has representation from all interested IEC
National Committees. The formal decisions of IEEE on technical matters, once consensus within IEEE Societies
and Standards Coordinating Committees has been reached, is determined by a balanced ballot of materially
interested parties who indicate interest in reviewing the proposed standard. Final approval of the IEEE
standards document is given by the IEEE Standards Association (IEEE-SA) Standards Board.
3) IEC/IEEE Publications have the form of recommendations for international use and are accepted by IEC
National Committees/IEEE Societies in that sense. While all reasonable efforts are made to ensure that the
technical content of IEC/IEEE Publications is accurate, IEC or IEEE cannot be held responsible for the way in
which they are used or for any misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
(including IEC/IEEE Publications) transparently to the maximum extent possible in their national and regional
publications. Any divergence between any IEC/IEEE Publication and the corresponding national or regional
publication shall be clearly indicated in the latter.
5) IEC and IEEE do not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC and IEEE are not responsible
for any services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or IEEE or their directors, employees, servants or agents including individual
experts and members of technical committees and IEC National Committees, or volunteers of IEEE Societies
and the Standards Coordinating Committees of the IEEE Standards Association (IEEE-SA) Standards Board,
for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect,
or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this
IEC/IEEE Publication or any other IEC or IEEE Publications.
8) Attention is drawn to the normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that implementation of this IEC/IEEE Publication may require use of
material covered by patent rights. By publication of this standard, no position is taken with respect to the
existence or validity of any patent rights in connection therewith. IEC or IEEE shall not be held responsible for
identifying Essential Patent Claims for which a license may be required, for conducting inquiries into the legal
validity or scope of Patent Claims or determining whether any licensing terms or conditions provided in
connection with submission of a Letter of Assurance, if any, or in any licensing agreements are reasonable or
non-discriminatory. Users of this standard are expressly advised that determination of the validity of any patent
rights, and the risk of infringement of such rights, is entirely their own responsibility.
International Standard IEC/IEEE 60780-323 has been prepared by subcommittee 45A:
Instrumentation, control and electrical systems of nuclear facilities, of IEC technical
committee 45: Nuclear instrumentation, in cooperation with the Nuclear Power Engineering
Committee of the Power & Energy Society of the IEEE, under the IEC/IEEE Dual Logo
Agreement between IEC and IEEE.

IEC/IEEE 60780-323:2016 – 5 –
© IEC/IEEE 2016
This publication is published as an IEC/IEEE Dual Logo standard.
NOTE A list of IEEE participants can be found at the following URL:
http://standards.ieee.org/downloads/60780/60780-323-2016/60780-323-2016_wg-participants.pdf
This new edition cancels and replaces the first edition of IEC 60780, published in 1998. It
constitutes a technical revision. It also supersedes IEEE Std 323-2003.
The main technical changes with regard to IEC 60780:1998 are as follows:
• to harmonize in a unique standard qualification practices formerly given by
IEC 60780:1998 and IEEE Std 323-2003 on initial qualification,
• to take into account the need to reassess and extend the qualified life of electrical
equipment regarding projects to extend the operating life of nuclear facilities.
This revision incorporates current practices and lessons learned from the implementation of
previous versions of this standard by the nuclear industry.
Several issues are clarified or changed in this revision:
• This standard defines the methods for equipment qualification when it is desired to qualify
equipment for the applications in the environments to which it may be exposed. This
standard is generally utilized for qualification of all electrical equipment important to safety
in accordance with IAEA terminology. The documentation and test requirements are,
however, more rigorous for equipment located in a harsh environment.
• The test margins have been updated to better identify the parameters that achieve test
margin on design basis event profiles.
• An important concept in equipment qualification is the recognition that significant
degradation could be caused by ageing mechanisms occurring from the environments
during the service life, and therefore equipment important to safety should be brought to
the end of qualified life (operating ageing) prior to imposing design basis event
simulations. Previous versions recognised that the period of time for which acceptable
performance was demonstrated is the qualified life. The qualified life does not include the
time during or after the accident conditions for which qualification is demonstrated
(mission time). The concept of qualified life continues in this revision. This revision also
recognises that the condition of the equipment for which acceptable performance was
demonstrated is the qualified condition. Thus, new license renewal and life extension
options are available by ensuring that qualified equipment continues to remain in a
qualified condition.
The text of this standard is based on the following IEC documents:
FDIS Report on voting
45A/1058/FDIS 45A/1075/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 website
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.
– 6 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
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 functional 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 qualification.
Other aspects, relating to quality assurance, reliability, selection and use of electronic
devices, design and modification of digital systems including 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,
– Significance of refinements in ageing mechanisms, equipment sealing, interfaces,
extrapolation, similarity, test sequence and parameters (such as ramp rates, time
duration, timing of spray initiation and its duration), and qualification documentation.
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 is a first level IEC SC 45A document and gives guidance applicable to I&C at
system level.
These documents are supplemented by guidance on functional classification (IEC 61226),
hardware design (IEC 60987), software (IEC 60880 and IEC 62138), selection and use of
HDL programmed integrated circuit (IEC 62566) and requirements in order to reduce the
possibility and limit the impact of common cause failure of category A functions
(IEC 62340).
IEC/IEEE 60780-323 is a second level IEC SC 45A document which focuses on
environmental 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.
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 including Class 1E equipment in accordance with the
IEEE classification scheme and Classes 1, 2 and 3 in accordance with IEC 61226
classification scheme.
For equipment that needs to be qualified for design extension conditions, including severe
accident conditions, this international standard shall be applied after a new DBE profile
covering these conditions has been fully defined. Conservatism taken into account to
define this severe accident profile should nevertheless be adapted.
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 document of the IEC SC 45A standard series is IEC 61513. It provides
general requirements for I&C systems and equipment that are used to perform functions
important to safety in NPPs. IEC 61513 structures the IEC SC 45A standard series.

IEC/IEEE 60780-323:2016 – 7 –
© IEC/IEEE 2016
IEC 61513 refers directly to other IEC SC 45A standards for general topics related to
categorisation of functions and classification of systems, qualification, separation of
systems, defence against common cause failure, software aspects of computer-based
systems, hardware aspects of computer-based systems, and control room design. The
standards referenced directly at this second level should be considered together with
IEC 61513 as a consistent document set.
At a third level, IEC SC 45A standards not directly referenced by IEC 61513 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 45A standard series, corresponds to the Technical
Reports which are not normative.
IEC 61513 has adopted a presentation format similar to the basic safety publication
IEC 61508 with an overall safety life-cycle framework and a system life-cycle framework.
Regarding nuclear safety, it provides the interpretation of the general requirements of
IEC 61508-1, IEC 61508-2 and IEC 61508-4, for the nuclear application sector, regarding
nuclear safety. In this framework IEC 60880 and IEC 62138 correspond to IEC 61508-3 for
the nuclear application sector. IEC 61513 refers to ISO as well as to IAEA GS-R-3 and
IAEA GS-G-3.1 and IAEA GS-G-3.5 for topics related to quality assurance (QA).
The IEC SC 45A standards series consistently implements and details the principles and
basic safety aspects provided in the IAEA code on the safety of NPPs and in the IAEA
safety series, in particular the Requirements SSR-2/1, establishing safety requirements
related to the design of Nuclear Power Plants, and the Safety Guide SSG-39 dealing with
instrumentation and control systems important to safety in Nuclear Power Plants. The
terminology and definitions used by SC 45A standards are consistent with those used by
the IAEA.
– 8 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
NUCLEAR FACILITIES – ELECTRICAL EQUIPMENT
IMPORTANT TO SAFETY – QUALIFICATION

1 Scope and object
This International Standard describes the basic requirements for qualifying electrical
equipment important to safety and interfaces (electrical and mechanical) that are to be used
in nuclear facilities. The principles, methods, and procedures described are intended to be
used for qualifying equipment, maintaining and extending qualification, and updating
qualification, as required, if the equipment is modified. The qualification requirements in this
standard, when met, demonstrate and document the ability of equipment to perform safety
function(s) under applicable service conditions, including design basis events and certain
design extension conditions, and reduce the risk of environmentally induced common-cause

equipment failure.
This standard does not provide environmental stress levels or performance requirements.
Other aspects, relating to quality assurance, selection and use of electronic devices, design
and modification of digital systems are not part of this standard.
Other IEC or IEEE standards that present qualification programmes for specific equipment,
specific environments, or specific parts of the qualification programme may be used to
supplement this standard, as applicable. The bibliography lists other standards related to
equipment qualification.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60980, Recommended practices for seismic qualification of electrical equipment of the
safety system for nuclear generating stations
IEEE Std 344™-2013, IEEE Standard for Seismic Qualification of Equipment for Nuclear
Power Generating Stations
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
age conditioning
process of subjecting equipment or a component to elevated stress conditions (environmental
and operational) in order to render its physical and electrical properties similar to those it
would have at a predetermined natural age when operating under expected operational
conditions, corresponding at least to the qualified life
3.2
ageing
general process in which characteristics of a system or component gradually change with
time or use
IEC/IEEE 60780-323:2016 – 9 –
© IEC/IEEE 2016
[SOURCE: IAEA Safety Glossary, 2007]
3.3
Class 1E
safety classification of the electrical equipment and systems that are essential to emergency
reactor shutdown, containment isolation, reactor core cooling, and containment and reactor
heat removal, or are otherwise essential in preventing significant release of radioactive
material to the environment
[SOURCE: IEEE Standards Dictionary Online]
3.4
common cause failure
failure of two or more structures, systems or components due to a single specific event or
cause
[SOURCE: IAEA Safety Glossary, 2007]
3.5
components
discrete elements of a system. Examples of components are wires, transistors, integrated
circuits, motors, relays, solenoids, pipes, fittings, pumps, tanks and valves
[SOURCE: IAEA Safety Glossary, 2007]
3.6
condition-based qualification
qualification based on measurement of one or more condition indicators of equipment, its
components, or materials for which an acceptance criterion can be correlated to the
equipment’s ability to function as specified during an applicable design basis event
[SOURCE: IEEE Standards Dictionary Online]
3.7
condition indicator
characteristic of equipment or its components that can be observed, measured and trended to
infer or directly indicate the current and future ability of equipment to function within
acceptance criteria in all specified service conditions (including DBE conditions)
3.8
design basis events
postulated events used in the design to establish the acceptable performance
requirements for the structures, systems, and components
[SOURCE: IEEE Standards Dictionary Online]
3.9
design extension conditions
accident conditions that are not considered for design basis events, but that are considered in
the design process of the facility in accordance with best estimate methodology, and for which
releases of radioactive material are kept within acceptable limits. Design extension conditions
include severe accident conditions.
___________
1 IEEE Standards Dictionary Online is available at:
http://ieeexplore.ieee.org/xpls/dictionary.jsp

– 10 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
[SOURCE: IAEA Safety Standards Series SSR2/1:2012]
3.10
end condition
value(s) of equipment condition indicator(s) at the conclusion of age conditioning
3.11
equipment
assembly of components designed and manufactured to perform specific functions
Note 1 to entry: Sensors, cables, electrically operated valves, I&C cabinet or racks are examples of
equipment.
[SOURCE: IEEE Standards Dictionary Online]
3.12
equipment important to safety
equipment that is part of a safety group and/or whose malfunction or failure could lead to
undue radiation exposure of the site personnel or members of the public. Equipment
including:
• those structures, systems and components that prevent anticipated operational
occurrences from leading to accident conditions;
• those features that are provided to mitigate the consequences of malfunction or failure
of structures, systems and components.
A) For usage consistent with IEC 61226, equipment important to safety are as follows:
– all I&C equipment performing Category A to Category C functions (in accordance
with the IEC 61226 categorisation scheme),
– all electrical equipment needed to ensure emergency energy supply to this
equipment in case of a loss of normal power supply,
– all electrical equipment needed to ensure ultimate energy supply in case of total
loss of on-site power (if selected as design extension condition to be mitigated).
B) For usage consistent with other IEEE documents and a Class 1E categorization;
for equipment important to safety, qualification is essential to the following:
– electric equipment and systems that are essential to emergency reactor
shutdown, containment isolation, reactor core cooling, and containment and
reactor heat removal, or
– electric equipment that are otherwise 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.
3.13
equipment qualification
generation and maintenance of evidence to ensure that equipment will operate on demand to
meet system performance requirements during normal and abnormal service conditions and
postulated design basis events
[SOURCE: IAEA Safety Glossary, 2007]
3.14
equipment similarity
demonstration of physical, operational and dynamic equivalency between equipment being
qualified and equipment previously qualified

IEC/IEEE 60780-323:2016 – 11 –
© IEC/IEEE 2016
3.15
harsh environment
environment that significantly changes as a result of a design basis event, e.g., loss-of-
coolant accident (LOCA), high-energy line break (HELB), and main steam line break (MSLB)
[SOURCE: IEEE Standards Dictionary Online]
3.16
interfaces
shared boundary between structures, systems and components that includes physical
attachments, mounting, auxiliary components, and connectors (electrical and mechanical)
to the equipment
3.17
margin
difference between service conditions and the conditions used for equipment qualification
[SOURCE: IEEE Standards Dictionary Online]
3.18
mild environment
environment that would at no time be significantly more severe than the environment that
would occur during normal plant operation, including anticipated operational occurrences
3.19
qualified condition
condition of equipment, prior to the start of a design basis event, for which the equipment
was demonstrated to meet the design requirements for the specified service conditions.
This could include certain post accident cooling and monitoring systems that are expected
to remain operational.
3.20
qualified life
period for which an equipment has been demonstrated, through testing, analysis and/or
experience, to be capable of functioning within acceptance criteria during specific operating
conditions while retaining the ability to perform its safety functions in accident condition or
earthquake
Note 1 to entry: This note applies to the French language only.
[SOURCE: IAEA Safety Glossary, 2007]
3.21
service conditions
actual physical states or influences during the service life of equipment, including normal
operating conditions, abnormal operating conditions, design basis event conditions and
conditions following a design basis event and design extension conditions
Note 1 to entry: In 2007-edition of IAEA safety glossary, accident conditions include both design basis accident
and beyond design basis accident. This second notion has been replaced within IAEA by the notion of design
extension conditions (AIEA, SSR-2/1). It explains the need of changing the definition.
[SOURCE: IAEA Safety Glossary, 2007, modified]
3.22
service life
period from initial operation to final withdrawal from service of a structure, system or
component
– 12 – IEC/IEEE 60780-323:2016
© IEC/IEEE 2016
[SOURCE: IAEA Safety Glossary, 2007]
3.23
severe accident
accident conditions more severe than a design basis event and involving significant core
degradation
[SOURCE: IAEA Safety Glossary, 2007]
3.24
significant ageing mechanism
ageing mechanism that, under normal and abnormal service conditions, causes
degradation of equipment that progressively and appreciably renders the equipment
vulnerable to failure to perform its safety function(s) during the design basis event
conditions
[SOURCE: IEEE Standards Dictionary Online]
4 Symbols and abbreviations
DBE Design Basis Event
EM Electromagnetic
EMC Electromagnetic Compatibility
EMI Electromagnetic Interference
HELB High Energy Line Break
I&C Instrumentation and Control
LOCA Loss of Coolant Accident
MSLB Main Steam Line Break
NPP Nuclear Power Plant
RFI Radio Frequency Interference
5 Principles of equipment qualification
5.1 Qualification objective
The primary objective of qualification is to demonstrate with reasonable assurance that
equipment important to safety can perform its safety function(s) without experiencing
common-cause failures before, during, and after applicable DBE.
Equipment important to safety, including its interfaces, shall meet or exceed the equipment
specification requirements. This continued capability is ensured through a programme that
includes, but is not limited to, design control, quality control, qualification, installation,
maintenance, periodic testing, and surveillance. The focus of this standard is on qualification,
although it affects the other parts of the programme.
For all items of equipment required to operate under design extension conditions,
demonstrable evidence shall be provided that it is able to perform its function(s) under the
applicable service conditions including design extension conditions.
Equipment located in normal and mild environments shall be specified, designed, and
selected to perform their functions in their intended service conditions including anticipated
operational occurrences. Requirements, including EMC, environmental/operational ageing and
seismic requirements shall be specified in the design/purchase specifications.

IEC/IEEE 60780-323:2016 – 13 –
© IEC/IEEE 2016
A maintenance/surveillance programme based on a vendor’s recommendations, which may be
supplemented with operating experience, should ensure that equipment meets the specified
performance requirements. A qualified life is not required for equipment located in a mild
environment and which has no significant ageing mechanisms and is operated within the
limits established by applicable specifications and standards. Qualification for equipment
located in mild environments shall be demonstrated by providing evidence that equipment
meets or exceeds the specified requirements, including those of recognized industry
associations. When seismic testing is used to qualify equipment located in a mild
environment, pre-ageing prior to the seismic tests is required only where significant ageing
mechanisms exist (see 7.3.3).
5.2 Qualified life and qualified condition
Degradation with time followed by exposure to the applicable environmental extremes of
temperature, pressure, humidity, radiation, vibration, chemical spray and submergence
resulting from a DBE condition can precipitate failures of equipment important to safety. For
this reason, it is necessary to establish a qualified life for equipment with significant ageing
mechanisms. The qualified life determination shall consider degradation of equipment
capability prior to, during and in post-accident conditions as applicable. Inherent in
establishing a qualified life is that a qualified condition is also established. This qualified
condition is the state of degradation for which successful performance during a subsequent
DBE was demonstrated.
A qualified life is established in initial qualification by putting test sample(s) in the state of
degradation expected at the end of the qualified life, followed by simulated DBE(s) in which
the ability of the equipment to perform its function important to safety is demonstrated.
Adjustment and extension of qualified life of existing equipment may be achieved through the
use of different techniques. These techniques are further described in 6.2.
5.3 Qualification elements
The preferred approach is qualification by type-testing. Other methods as described in 7.4.3
and 7.4.4 are also applicable.
Essential elements needed to demonstrate equipment qualification shall include the following:
• equipment specification including the required safety function(s),
• acceptance criteria,
• description of the service conditions, including DBEs and their duration,
• qualification programme plan,
• implementation of the plan,
• documentation demonstrating successful qualification.
5.4 Qualification documentation
The result of a quali
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