EN 61226:2010

SLOVENSKI STANDARD
01-september-2010
Jedrske elektrarne - Merilna in nadzorna oprema za zagotavljanje varnosti -
Klasifikacija funkcij merilne in nadzorne opreme (IEC 61226:2009)
Nuclear power plants - Instrumentation and control important to safety - Classification of
instrumentation and control functions (IEC 61226:2009)
Kernkraftwerke - Leittechnische Systeme mit sicherheitstechnischer Bedeutung -
Kategorisierung leittechnischer Funktionen (IEC 61226:2009)
Centrales nucléaires de puissance - Instrumentation et contrôle-commande importants
pour la sûreté - Classification des fonctions d'instrumentation et de contrôle-commande
(CEI 61226:2009)
Ta slovenski standard je istoveten z: EN 61226:2010
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 61226
NORME EUROPÉENNE
March 2010
EUROPÄISCHE NORM
ICS 27.120.20
English version
Nuclear power plants -
Instrumentation and control important to safety -
Classification of instrumentation and control functions
(IEC 61226:2009)
Centrales nucléaires de puissance -  Kernkraftwerke -
Instrumentation et contrôle-commande Leittechnische Systeme
importants pour la sûreté - mit sicherheitstechnischer Bedeutung -
Classification des fonctions Kategorisierung leittechnischer
d'instrumentation Funktionen
et de contrôle-commande (IEC 61226:2009)
(CEI 61226:2009)
This European Standard was approved by CENELEC on 2010-03-01. 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 Central Secretariat 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 Central Secretariat 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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: Avenue Marnix 17, B - 1000 Brussels

© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61226:2010 E
Foreword
The text of the International Standard IEC 61226:2009, prepared by SC 45A, Instrumentation and control
of nuclear facilities, of IEC TC 45, Nuclear instrumentation, was submitted to the CENELEC formal vote
for acceptance as a European Standard and was approved by CENELEC as EN 61226 on 2010-03-01.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates are proposed:
– latest date by which the EN has to be implemented

at national level by publication of an identical

national standard or by endorsement
(dop) 2011-03-01
– latest date by which the national standards conflicting

with the EN have to be withdrawn
(dow) 2013-03-01
Annex ZA has been added by CENELEC.
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 measures in the subject-matter covered
by this European Standard.
__________
– 3 – EN 61226:2010
Endorsement notice
The text of the International Standard IEC 61226:2009 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.
__________
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application 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  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
IEC 60671 2007 Nuclear power plants - Instrumentation and -
-
control systems important to safety - Surveillance
testing
IEC 60709 - Nuclear power plants - Instrumentation and -
-
control systems important to safety - Separation
IEC 60780 - Nuclear power plants - Electrical equipment of the -
-
safety system - Qualification
IEC 60812 - Analysis techniques for system reliability - EN 60812 -
Procedure for failure mode and effects analysis
(FMEA)
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 60964 - Nuclear power plants - Control rooms - Design EN 60964 -
IEC 60965 - Nuclear power plants - Control rooms - -
-
Supplementary control points for reactor shutdown
without access to the main control room
IEC 60980 - Recommended practices for seismic qualification - -
of electrical equipment of the safety system for
nuclear generating stations
IEC 60987 - Nuclear power plants - Instrumentation and EN 60987 -
control important to safety - Hardware design
requirements for computer-based systems
IEC 61000-4 Series Electromagnetic compatibility (EMC) - EN 61000-4 Series
Part 4: Testing and measurement techniques
IEC 61000-6-2 - Electromagnetic compatibility (EMC) - EN 61000-6-2 -
Part 6-2: Generic standards - Immunity for
industrial environments
IEC 61513 2001 Nuclear power plants - Instrumentation and - -
control for systems important to safety -
General requirements for systems

– 5 – EN 61226:2010
Publication Year Title EN/HD Year
IEC 61771 - Nuclear power plants - Main control-room - - -
Verification and validation of design
IEC 61772 - Nuclear power plants - Control rooms - Application - -
of visual display units (VDUs)
IEC 61839 - Nuclear power plants - Design of control rooms - - -
Functional analysis and assignment
IEC 62138 - Nuclear power plants - Instrumentation and EN 62138 -
control important for safety - Software aspects for
computer-based systems performing category B
or C functions
IAEA NS-R-1 2000 Safety of nuclear power plants: Design - -
IAEA GS-R-3 2006 The management system for facilities and - -
activities : safety requirements
IAEA NS-G-1.3 2002 Instrumentation and control systems important to - -
safety in nuclear power plants

IEC 61226 ®
Edition 3.0 2009-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control important to safety –
Classification of instrumentation and control functions

Centrales nucléaires de puissance – Instrumentation et contrôle-commande
importants pour la sûreté – Classement des fonctions d’instrumentation et de
contrôle-commande
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 27.120.20 ISBN 2-8318-1052-1
– 2 – 61226 © IEC:2009
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.8
2 Normative references .8
3 Terms and definitions .9
4 Abbreviations .13
5 Classification scheme.13
5.1 General .13
5.2 Background .14
5.3 Description of categories.14
5.3.1 General .14
5.3.2 Category A .15
5.3.3 Category B .15
5.3.4 Category C .15
5.4 Assignment criteria.16
5.4.1 General .16
5.4.2 Category A .16
5.4.3 Category B .16
5.4.4 Category C .17
6 Classification procedure .17
6.1 General .17
6.2 Identification of design basis .18
6.3 Identification and classification of functions.18
7 Assignment of technical requirements to categories .21
7.1 General requirements.21
7.2 Requirements related to functions .21
7.2.1 Basic requirements.21
7.2.2 Specific requirements .22
7.3 Requirements related to I&C systems.22
7.3.1 Basic requirements.22
7.3.2 Specific requirements .23
7.4 Requirements related to equipment .25
7.4.1 Basic requirements.25
7.4.2 Specific requirements .25
7.5 Requirements related to quality aspects .26
7.5.1 Basic requirements.26
7.5.2 Specific requirements .26
Annex A (informative) Examples of categories .30
Bibliography.32

Figure 1 – Method of classification.20

Table 1 – Tabular correlation between categories and other IEC standards .29

61226 © IEC:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL IMPORTANT TO SAFETY –
CLASSIFICATION OF INSTRUMENTATION AND CONTROL 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 re
...