IEC 61500:2018

Nuclear power plants - Instrumentation and control systems important to safety - Data communication in systems performing category A functions

IEC 61500:2018 establishes requirements for data communication which is used in systems performing category A functions in nuclear power plants. It covers also interface requirements for data communication of equipment performing category A functions with other systems including those performing category B and C functions and functions not important to safety. This document gives requirements for functions and properties of on-line plant data communication by reference to IEC 60880 and IEC 60987, produced within the framework of IEC 61513. It requires categorisation of the communication functions in accordance with IEC 61226. This new edition includes the following significant technical changes with respect to the previous edition:
- the changes introduced to previously referenced standards have been confirmed to apply;
- relevant newly published standards have been referenced;
- lessons learned from several industrial applications have been incorporated.

Centrales nucléaires de puissance - Systèmes d'instrumentation et de contrôle-commande importants pour la sûreté - Communications de données dans les systèmes réalisant des fonctions de catégorie A

IEC 61500:2018 établit des exigences applicables à la communication de données assurée pour des systèmes réalisant des fonctions de catégorie A dans les centrales nucléaires de puissance. Cela comprend aussi les exigences relatives aux interfaces des équipements de communication de données assurant des fonctions de catégorie A, avec les autres systèmes y compris ceux qui assurent des fonctions de catégories B et C, ainsi que des fonctions non importantes pour la sûreté. Ce document fournit des exigences pour les fonctions et les propriétés afférentes à la communication de données en faisant référence aux IEC 60880 et IEC 60987, qui ont été développées sous couvert de l’IEC 61513. Cela implique que les fonctions de communication soient classées conformément à l’IEC 61226. Les principales modifications techniques par rapport à l'édition précédente sont les suivantes:
- les modifications introduites dans les normes précédemment référencées sont applicables;
- des normes pertinentes récemment publiées sont référencées;
- le retour d’expérience obtenu au niveau de plusieurs applications industrielles a été pris en compte.

General Information

• Status: Published
• Publication Date: 19-Apr-2018
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 27.120.20 - Nuclear power plants. Safety
• Technical Committee: SC 45A - Instrumentation, control and electrical power systems of nuclear facilities
• Drafting Committee: WG 3 - TC 45/SC 45A/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 27-Apr-2018
• Completion Date: 20-Apr-2018

Relations

• Revises: IEC 61500:2009 - Nuclear power plants - Instrumentation and control important to safety - Data communication in systems performing category A functions
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61500 ®
Edition 3.0 2018-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants – Instrumentation and control systems important to
safety – Data communication in systems performing category A functions

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

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IEC 61500 ®
Edition 3.0 2018-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants – Instrumentation and control systems important to

safety – Data communication in systems performing category A functions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.120.20 ISBN 978-2-8322-5625-1

– 2 – IEC 61500:2018 RLV  IEC 2018

CONTENTS
FOREWORD . 3
INTRODUCTION . 2
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Symbols and abbreviated terms . 11
5 General requirements . 11
5.1 Principles of selection of data communication techniques and equipment . 11
5.2 Functional requirements . 11
5.3 Performance requirements . 12
Failure detection .
5.4 Communication within and between division . 13
5.5 Interfaces to systems of lower importance to safety . 13
6 Electrical isolation and physical separation . 13
6.1 Electrical isolation . 13
6.2 Physical separation . 13
7 Functional independence . 14
8 Reliability . 14
8.1 Self-supervision and failure mitigation . 14
8.1.1 Communication error detection . 14
8.1.2 Response to failure . 15
8.2 Testing . 15
8.3 Prevention of failures (including CCF) . 16
8.4 Cybersecurity . 17
9 Qualification . 17
10 Maintenance and modification . 17
Bibliography . 18

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS IMPORTANT TO SAFETY –
DATA COMMUNICATION IN SYSTEMS PERFORMING
CATEGORY A FUNCTIONS
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. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements 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.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC 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
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is 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 its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees 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 Publication or any other IEC
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 some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

– 4 – IEC 61500:2018 RLV  IEC 2018
International Standard IEC 61500 has been prepared by subcommittee 45A: Instrumentation,
control and electrical power systems of nuclear facilities, of IEC technical committee 45:
Nuclear instrumentation.
This third edition cancels and replaces the second edition published in 2009. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the changes introduced to previously referenced standards have been confirmed to apply;
b) relevant newly published standards have been referenced;
c) lessons learned from several industrial applications have been incorporated.
The text of this standard is based on the following documents:
FDIS Report on voting
45A/1183/FDIS 45A/1194/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has 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.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

INTRODUCTION
a) Technical background, main issues and organization of the standard
The equipment for data communication of on-line plant data can simplify the hardwired cables
connecting distributed systems for instrumentation, control, protection and monitoring needed
for the safe operation of Nuclear Power Plants (NPP). Such communication systems can have
advantages over direct cables, for electrical isolation, for reduction of cable fire loads or other
reasons. In a distributed computer based system, communication equipment is an essential
part of the system. Data communication is usually essential for implementing I&C systems
important to safety in nuclear power plants.
It is intended that the document be used by operators of NPPs (utilities), manufacturers of
data communication equipment, systems evaluators and by licensors.
b) Situation of the current standard in the structure of the IEC SC 45A standard series
IEC 61500 is the third level IEC SC 45A document tackling the generic issue of data
communication for equipment performing category A functions.
IEC 61500 is to be read in association with IEC 61513, which is the appropriate IEC SC 45A
document providing guidance on general requirements for instrumentation and control
systems important to safety, IEC 60880, which is the appropriate IEC SC 45A document
providing guidance on software aspects for computer based systems performing category A
functions, and IEC 60987 which is the appropriate IEC SC 45A document providing guidance
on hardware aspects for computer based systems.
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 the standard
It is important to note that this standard establishes no additional functional requirements for
safety systems.
Aspects for which special recommendations have been provided in this standard are:
• Requirements for data communication within systems performing category A functions.
• Requirements for data communication between divisions of a system performing
category A functions.
• Requirements for data communication of systems performing category A func
...

IEC 61500 ®
Edition 3.0 2018-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control systems important to
safety – Data communication in systems performing category A functions

Centrales nucléaires de puissance – Systèmes d’instrumentation et de contrôle-
commande importants pour la sûreté – Communications de données dans les
systèmes réalisant des fonctions de catégorie A

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

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bibliographical information on IEC International Standards, electrical terms containing 21 000 terms and definitions in
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documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

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IEC 61500 ®
Edition 3.0 2018-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control systems important to

safety – Data communication in systems performing category A functions

Centrales nucléaires de puissance – Systèmes d’instrumentation et de contrôle-

commande importants pour la sûreté – Communications de données dans les

systèmes réalisant des fonctions de catégorie A

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-5583-4

– 2 – IEC 61500:2018  IEC 2018

CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 10
5 General requirements . 10
5.1 Principles of selection of data communication techniques and equipment . 10
5.2 Functional requirements . 10
5.3 Performance requirements . 11
5.4 Communication within and between division . 11
5.5 Interfaces to systems of lower importance to safety . 11
6 Electrical isolation and physical separation . 12
6.1 Electrical isolation . 12
6.2 Physical separation . 12
7 Functional independence . 12
8 Reliability . 13
8.1 Self-supervision and failure mitigation . 13
8.1.1 Communication error detection . 13
8.1.2 Response to failure . 13
8.2 Testing . 14
8.3 Prevention of failures (including CCF) . 14
8.4 Cybersecurity . 15
9 Qualification . 15
10 Maintenance and modification . 15
Bibliography . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS IMPORTANT TO SAFETY –
DATA COMMUNICATION IN SYSTEMS PERFORMING
CATEGORY A FUNCTIONS
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. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements 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.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC 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
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is 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 its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees 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 Publication or any other IEC
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 some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61500 has been prepared by subcommittee 45A: Instrumentation,
control and electrical power systems of nuclear facilities, of IEC technical committee 45:
Nuclear instrumentation.
This third edition cancels and replaces the second edition published in 2009. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the changes introduced to previously referenced standards have been confirmed to apply;
b) relevant newly published standards have been referenced;
c) lessons learned from several industrial applications have been incorporated.

– 4 – IEC 61500:2018  IEC 2018
The text of this standard is based on the following documents:
FDIS Report on voting
45A/1183/FDIS 45A/1194/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged unti
...