Nuclear power plants - Instrumentation and control systems - Requirements for coordinating safety and cybersecurity (IEC 62859:2016+A1:2019)

This document provides a framework to manage the interactions between safety and
cybersecurity for nuclear power plant (NPP) systems, taking into account the current SC 45A
standards addressing these issues and the specifics of nuclear I&C programmable digital
systems.
NOTE In this document (as in IEC 62645), cybersecurity relates to prevention of, detection of, and reaction to
malicious acts perpetrated by digital means (cyberattacks). In this context, it does not cover considerations related
to non-malevolent actions and events such as accidental failures, natural events or human errors (except those
degrading cybersecurity). Those aspects are of course of prime importance but they are covered by other SC 45A
documents and standards, and are not considered as cybersecurity related in this document.
This document establishes requirements and guidance to:
– integrate cybersecurity provisions in nuclear I&C architectures and systems, which are
fundamentally tailored for safety;
– avoid potential conflicts between safety and cybersecurity provisions;
– aid the identification and the leveraging of the potential synergies between safety and
cybersecurity.
This document is intended to be used for designing new NPPs, or modernizing existing NPPs,
throughout I&C programmable digital systems lifecycle. It is also applicable for assessing the
coordination between safety and cybersecurity of existing plants. It may also be applicable to
other types of nuclear facilities.
This document addresses I&C programmable digital systems important to safety and I&C
programmable digital systems not important to safety. It does not address programmable
digital systems dedicated to site physical security, room access control and site security
surveillance.
This document is limited to I&C programmable digital systems of NPPs, including their on-site
maintenance and configuration tools.
Annex A provides a rationale for and comments about the scope definition and the document
application, in particular about the exclusions and limitations previously mentioned.
This document comprises three normative clauses:
• Clause 5 deals with the overall I&C architecture;
• Clause 6 focuses on the system level;
• Clause 7 deals with organizational and operational issues.

Kernkraftwerke - Leittechnische Systeme - Anforderungen für die Koordinierung von Sicherheit und IT-Sicherheit (IEC 62859:2016+A1:2019)

Centrales nucléaires de puissance - Systèmes d'instrumentation et de contrôle-commande - Exigences pour coordonner sûreté et cybersécurité (IEC 62859:2016+A1:2019)

Jedrske elektrarne - Merilna in nadzorna oprema - Zahteve za usklajevanje varnosti in kibernetske varnosti (IEC 62859:2016+A1:2019)

General Information

Status
Published
Public Enquiry End Date
11-Jun-2020
Publication Date
14-Sep-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Sep-2020
Due Date
16-Nov-2020
Completion Date
15-Sep-2020

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SLOVENSKI STANDARD
SIST EN IEC 62859:2020
01-november-2020
Jedrske elektrarne - Merilna in nadzorna oprema - Zahteve za usklajevanje
varnosti in kibernetske varnosti (IEC 62859:2016+A1:2019)
Nuclear power plants - Instrumentation and control systems - Requirements for
coordinating safety and cybersecurity (IEC 62859:2016+A1:2019)

Kernkraftwerke - Leittechnische Systeme - Anforderungen für die Koordinierung von

Sicherheit und IT-Sicherheit (IEC 62859:2016+A1:2019)
Centrales nucléaires de puissance - Systèmes d'instrumentation et de contrôle-
commande - Exigences pour coordonner sûreté et cybersécurité (IEC
62859:2016+A1:2019)
Ta slovenski standard je istoveten z: EN IEC 62859:2020
ICS:
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
SIST EN IEC 62859:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 62859:2020
---------------------- Page: 2 ----------------------
SIST EN IEC 62859:2020
EUROPEAN STANDARD EN IEC 62859
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2020
ICS 27.120.20
English Version
Nuclear power plants - Instrumentation and control systems -
Requirements for coordinating safety and cybersecurity
(IEC 62859:2016 + A1:2019)

Centrales nucléaires de puissance - Systèmes Kernkraftwerke - Leittechnische Systeme - Anforderungen

d'instrumentation et de contrôle-commande - Exigences für die Koordinierung von Sicherheit und IT-Sicherheit

pour coordonner sûreté et cybersécurité (IEC 62859:2016 + A1:2019)
(IEC 62859:2016 + A1:2019)

This European Standard was approved by CENELEC on 2020-07-20. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, 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: Rue de la Science 23, B-1040 Brussels

© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 62859:2020 E
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SIST EN IEC 62859:2020
EN IEC 62859:2020 (E)
European foreword

The text of document 45A/1104/FDIS, future IEC 62859/A1, prepared by SC 45A "Instrumentation,

control and electrical power systems of nuclear facilities" of IEC/TC 45 "Nuclear instrumentation" was

submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 62859:2020.

The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2021-07-20

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2023-07-20

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 62859:2016/A1:2019 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 61508-1 NOTE Harmonized as EN 61508-1
IEC 61508-2 NOTE Harmonized as EN 61508-2
IEC 61508-3 NOTE Harmonized as EN 61508-3
IEC 61508-4 NOTE Harmonized as EN 61508-4
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SIST EN IEC 62859:2020
EN IEC 62859:2020 (E)
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 60709 2004 Nuclear power plants - Instrumentation and EN 60709 2010
control systems important to safety -
Separation
IEC 60880 2006 Nuclear power plants - Instrumentation and EN 60880 2009
control systems important to safety -
Software aspects for computer-based
systems performing category A functions
IEC 61500 2009 Nuclear power plants - Instrumentation and EN 61500 2011
control important to safety - Data
communication in systems performing
category A functions
IEC 61513 2011 Nuclear power plants - Instrumentation and EN 61513 2013
control important to safety - General
requirements for systems
IEC 62138 2004 Nuclear power plants - Instrumentation and EN 62138 2009
control important for safety - Software
aspects for computer-based systems
performing category B or C functions
IEC 62340 - Nuclear power plants - Instrumentation and EN 62340 -
control systems important to safety -
Requirements for coping with common
cause failure (CCF)
IEC 62566 2012 Nuclear power plants - Instrumentation and EN 62566 2014
control important to safety - Development
of HDL-programmed integrated circuits for
systems performing category A functions
IEC 62646 2016 Nuclear power plants - Control rooms - EN IEC 62646 2019
Computer-based procedures
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SIST EN IEC 62859:2020
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SIST EN IEC 62859:2020
IEC 62859
Edition 1.0 2016-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control systems – Requirements for
coordinating safety and cybersecurity
Centrales nucléaires de puissance – Systèmes d'instrumentation et de contrôle-
commande – Exigences pour coordonner sûreté et cybersécurité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-3719-9

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 62859:2020
– 2 – IEC 62859:2016 © IEC 2016
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 9

4 Symbols and abbreviations ............................................................................................ 11

5 Coordinating safety and cybersecurity at the overall architecture level .......................... 12

5.1 General ................................................................................................................. 12

5.2 Fundamental and generic principles ...................................................................... 12

5.3 Thematic requirements and recommendations ...................................................... 13

5.3.1 Delineation of security zones ......................................................................... 13

5.3.2 Provisions for coping with common cause failures (including diversity) .......... 13

5.3.3 Separation provisions .................................................................................... 14

5.3.4 Data communications .................................................................................... 14

6 Coordinating safety and cybersecurity at the individual system level.............................. 14

6.1 General ................................................................................................................. 14

6.2 Fundamental and generic principles ...................................................................... 14

6.3 Safety and cybersecurity coordination during the I&C system lifecycle .................. 15

6.3.1 General ......................................................................................................... 15

6.3.2 Requirements and planning activities ............................................................. 15

6.3.3 Design activities ............................................................................................ 15

6.3.4 Implementation activities ............................................................................... 16

6.3.5 Verification and validation activities ............................................................... 16

6.3.6 Installation and acceptance testing activities ................................................. 16

6.3.7 Operations and maintenance activities........................................................... 16

6.3.8 Change management ..................................................................................... 16

6.3.9 Decommissioning activities ............................................................................ 16

6.4 Selected technical aspects of I&C systems constrained by safety and

cybersecurity ........................................................................................................ 17

6.4.1 General ......................................................................................................... 17

6.4.2 Logical access control for HMIs of I&C programmable digital systems in

control rooms ................................................................................................. 17

6.4.3 Software modification .................................................................................... 17

6.4.4 Logging and audit capability .......................................................................... 18

6.4.5 Use of cryptography by I&C systems ............................................................. 18

6.4.6 System availability and function continuity ..................................................... 19

7 Organizational and operational issues ........................................................................... 19

7.1 Governance and responsibilities ........................................................................... 19

7.2 Coordination between safety and cybersecurity staff during operations ................. 19

7.3 Safety and cybersecurity culture ........................................................................... 19

7.4 Emergency response management ....................................................................... 19

Annex A (informative) Rationale for, and notes related to, the scope of this document ......... 21

A.1 General ................................................................................................................. 21

A.2 Inclusion of I&C programmable digital system not important to safety ................... 21

A.3 Exclusion of physical security, room access control and site security

surveillance systems ............................................................................................. 21

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IEC 62859:2016 © IEC 2016 – 3 –

A.4 Exclusion of non-malevolent actions and events ................................................... 21

A.5 Exclusion of development tools and platforms ....................................................... 22

Bibliography .......................................................................................................................... 23

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SIST EN IEC 62859:2020
– 4 – IEC 62859:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS –
REQUIREMENTS FOR COORDINATING SAFETY AND CYBERSECURITY
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 62859 has been prepared by subcommittee 45A: Instrumentation,

control and electrical systems of nuclear facilities, of IEC technical committee 45: Nuclear

instrumentation.
The text of this standard is based on the following documents:
FDIS Report on voting
45A/1104/FDIS 45A/1118/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.

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SIST EN IEC 62859:2020
IEC 62859:2016 © IEC 2016 – 5 –

The committee has 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.
---------------------- Page: 11 ----------------------
SIST EN IEC 62859:2020
– 6 – IEC 62859:2016 © IEC 2016
INTRODUCTION
a) Technical background, main issues and organisation of this standard

I&C systems have evolved during the last decades from non-digital equipment and stand-

alone environments to digital technologies and interconnected systems. Such an evolution

exposes them to risks related to cyberattacks. In addition to well-established safety-oriented

provisions, more recent cybersecurity requirements and controls now apply to the same

systems. A normative framework is needed to master the interactions and potential side-

effects when safety and cybersecurity provisions converge on the same I&C systems and

architectures, taking into account the nuclear I&C specifics and the SC 45A related standards.

This standard specifically focuses on the issue of requirements for coordinating safety and

cybersecurity provisions for I&C programmable digital systems and architectures. It defines

both generic principles and guidance for practical situations to integrate cybersecurity

requirements in nuclear I&C architectures and systems, fundamentally tailored for safety.

Technical but also conceptual, organizational and procedural aspects are covered.

It is intended that this standard be used by designers and operators of nuclear power plants

(NPPs) (utilities), systems evaluators, vendors and subcontractors, and by licensors.

b) Situation of the current standard in the structure of the IEC SC 45A standard
series

IEC 62859 is at the second level of the IEC SC 45A standard series. It is to be considered as

bridging IEC 62645 (also at the second level of the IEC SC 45A standard series) and

IEC 61513, the top level document of the IEC SC 45A standard series. Regarding the specific

theme of cybersecurity, IEC 62645 is the top-level in the SC 45A standard series. Both

IEC 62645 and IEC 62859 are considered formally as second level documents with respect to

IEC 61513, although IEC 61513:2011 does not actually ensure proper reference to and

consistency with them (this will be done in a future revision of IEC 61513).

For a generic description of 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

It is important to note that this standard establishes additional requirements for I&C

programmable digital systems and architectures, with regard to the coordination between

safety and cybersecurity, and clarifies the processes by which I&C programmable digital

systems are designed, implemented and operated in nuclear power plants. Aspects for which

special requirements and recommendations have been produced are:
– IAEA guidance on I&C;
– IAEA guidance on computer security at nuclear facilities;
– regulatory interpretations for country specific requirements.

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

___________
In preparation. Stage at the time of publication: IEC ANW 63046:2016.
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SIST EN IEC 62859:2020
IEC 62859:2016 © IEC 2016 – 7 –

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 (NPP), the IAEA safety guide SSG-30 dealing with the safety classification of

structures, systems and components in NPP, the IAEA safety guide SSG-39 dealing with the

design of instrumentation and control systems for NPP, the IAEA safety guide SSG-34 dealing

with the design of electrical power systems for NPP and the implementing guide NSS17 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.

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-3 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, regarding control rooms, IEC 60964 is the entry document for the IEC SC 45A control

rooms standards and IEC 62342 is the entry document for the IEC SC 45A 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 will be published this NOTE 2 of the introduction of IEC SC 45A standards will be

suppressed.
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SIST EN IEC 62859:2020
– 8 – IEC 62859:2016 © IEC 2016
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS –
REQUIREMENTS FOR COORDINATING SAFETY AND CYBERSECURITY
1 Scope
This document provides a framework to manage the interactions between safety and

cybersecurity for nuclear power plant (NPP) systems, taking into account the current SC 45A

standards addressing these issues and the specifics of nuclear I&C programmable digital

systems.

NOTE In this document (as in IEC 62645), cybersecurity relates to prevention of, detection of, and reaction to

malicious acts perpetrated by digital means (cyberattacks). In this context, it does not cover considerations related

to non-malevolent actions and events such as accidental failures, natural events or human errors (except those

degrading cybersecurity). Those aspects are of course of prime importance but they are covered by other SC 45A

documents and standards, and are not considered as cybersecurity related in this document.

This document establishes requirements and guidance to:

– integrate cybersecurity provisions in nuclear I&C architectures and systems, which are

fundamentally tailored for safety;
– avoid potential conflicts between safety and cybersecurity provisions;

– aid the identification and the leveraging of the potential synergies between safety and

cybersecurity.

This document is intended to be used for designing new NPPs, or modernizing existing NPPs,

throughout I&C programmable digital systems lifecycle. It is also applicable for assessing the

coordination between safety and cybersecurity of existing plants. It may also be applicable to

other types of nuclear facilities.

This document addresses I&C programmable digital systems important to safety and I&C

programmable digital systems not important to safety. It does not address programmable

digital systems dedicated to site physical security, room access control and site security

surveillance.

This document is limited to I&C programmable digital systems of NPPs, including their on-site

maintenance and configuration tools.

Annex A provides a rationale for and comments about the scope definition and the document

application, in particular about the exclusions and limitations previously mentioned.

This document comprises three normative clauses:
• Clause 5 deals with the overall I&C architecture;
• Clause 6 focuses on the system level;
• Clause 7 deals with organizational and operational issues.
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.
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SIST EN IEC 62859:2020
IEC 62859:2016 © IEC 2016 – 9 –

IEC 60709:2004, Nuclear power plants – Instrumentation and control systems important to

safety – Separation

IEC 60880:2006, Nuclear power plants – Instrumentation and control systems important to

safety – Software aspects for computer-based systems performing category A functions

IEC 61500:2009, Nuclear power plants – Instrumentation and control systems important to

safety – Data communication in systems performing category A functions

IEC 61513:2011, Nuclear power plants – Instrumentation and control important to safety –

General
...

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