Nuclear power plants - Main control room - Alarm functions and presentation (IEC 62241:2004)

Provides the functional requirements for the alarm systems in the main control room of nuclear power plants. Establishes the human factors requirements and the design guidelines for alarm presentation for the main control room of nuclear power plants.

Kernkraftwerke - Warte - Alarmfunktionen und ihre Darstellung (IEC 62241:2004)

Centrales nucléaires de puissance - Salle de commande principale - Fonctions et présentation des alarmes (IEC 62241:2004)

Fournit les exigences fonctionnelles applicables aux systèmes d'alarme des salles de commande principales des centrales nucléaires de puissance. Etablit aussi les exigences relatives aux facteurs humains ainsi que les lignes directrices pour la conception de la présentation des alarmes dans la salle principale de commande des centrales nucléaires.

Jedrske elektrarne - Glavni komandni prostor - Funkcije alarma in predstavitev (IEC 62241:2004)

Standard zagotavlja funkcionalne zahteve za alarmne sisteme v glavnem komandnem prostoru jedrskih elektrarn. Določa zahteve glede človeških dejavnikov in smernice glede načrtovanja za predstavitev alarma za glavni komandni prostor jedrskih elektrarn.

General Information

Status
Published
Publication Date
04-Aug-2015
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
29-Jan-2015
Due Date
05-Apr-2015
Completion Date
05-Aug-2015

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SLOVENSKI STANDARD
SIST EN 62241:2015
01-september-2015
Jedrske elektrarne - Glavni komandni prostor - Funkcije alarma in predstavitev
(IEC 62241:2004)
Nuclear power plants - Main control room - Alarm functions and presentation (IEC
62241:2004)
Kernkraftwerke - Warte - Alarmfunktionen und ihre Darstellung (IEC 62241:2004)
Centrales nucléaires de puissance - Salle de commande principale - Fonctions et
présentation des alarmes (IEC 62241:2004)
Ta slovenski standard je istoveten z: EN 62241:2015
ICS:
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
SIST EN 62241:2015 en

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

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SIST EN 62241:2015
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SIST EN 62241:2015
EUROPEAN STANDARD EN 62241
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2015
ICS 27.120.20
English Version
Nuclear power plants - Main control room - Alarm functions and
presentation
(IEC 62241:2004)

Centrales nucléaires de puissance - Salle de commande Kernkraftwerke - Warte - Alarmfunktionen und ihre

principale - Fonctions et présentation des alarmes Darstellung
(IEC 62241:2004) (IEC 62241:2004)

This European Standard was approved by CENELEC on 2015-02-16. 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, 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

© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 62241:2015 E
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SIST EN 62241:2015
EN 62241:2015 - 2 -
Foreword
This document (EN 62241:2015) consists of the text of IEC 62241:2004 prepared by

SC 45A “Instrumentation, control and electrical systems of nuclear facilities” of IEC/TC 45 “Nuclear

instrumentation".
The following dates are fixed:
• latest date by which the document has to be (dop) 2016-02-16
implemented
at national level by publication of an identical
national standard or by endorsement
(dow) 2018-02-16
• latest date by which the national standards conflicting
with the document have to be withdrawn

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 standard.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 62241:2004 was approved by CENELEC as a European

Standard without any modification.
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SIST EN 62241:2015
- 3 - EN 62241:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 When 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 60964 1989 Design for control rooms of nuclear - -
power plants
IEC 61226 - Nuclear power plants - Instrumentation EN 61226 -
and control important to safety -
Classification of instrumentation and
control functions
IEC 61771 - Nuclear power plants - Main control-room - - -
Verification and validation of design
IEC 61772 - Nuclear power plants - Control rooms - EN 61772 -
Application of visual display units (VDUs)
IEC 61839 - Nuclear power plants - Design of control EN 61839 -
rooms - Functional analysis and
assignment
Superseded by IEC 60964:2009.
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SIST EN 62241:2015
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SIST EN 62241:2015
NORME CEI
INTERNATIONALE
IEC
62241
INTERNATIONAL
Première édition
STANDARD
First edition
2004-11
Centrales nucléaires de puissance –
Salle de commande principale –
Fonctions et présentation des alarmes
Nuclear power plants –
Main control room –
Alarm functions and presentation
 IEC 2004 Droits de reproduction réservés  Copyright - all rights reserved

Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any

utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including

électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from

microfilms, sans l'accord écrit de l'éditeur. the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

CODE PRIX
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Pour prix, voir catalogue en vigueur
For price, see current catalogue
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SIST EN 62241:2015
62241  IEC:2004 – 3 –
CONTENTS

FOREWORD...........................................................................................................................7

INTRODUCTION...................................................................................................................11

1 Scope and object............................................................................................................15

2 Normative references .....................................................................................................15

3 Terms and definitions.......................................................................................................17

4 Background explanations ...............................................................................................25

4.1 Problems of alarm systems ...................................................................................25

4.2 Functional design elements ...................................................................................27

4.3 Other elements......................................................................................................27

5 Basic functional requirements.........................................................................................31

5.1 Alarm functions .....................................................................................................31

5.2 Alarm signals ........................................................................................................31

5.3 Alarm signal processing ........................................................................................33

5.4 Alarm display processing.......................................................................................35

5.5 Alarm control and management .............................................................................35

5.6 Alarm presentation and display-control integration ................................................37

5.7 Human factors.......................................................................................................37

5.8 Evaluation .............................................................................................................39

6 Design definition of alarms .............................................................................................39

6.1 General .................................................................................................................39

6.2 Key alarms ............................................................................................................41

6.3 Alarms needed ......................................................................................................41

7 Alarm signal processing .................................................................................................43

7.1 General .................................................................................................................43

7.2 Alarm signal validation ..........................................................................................43

7.3 Alarm generation and reduction processing ...........................................................43

7.4 Event sequence and time delay processing ...........................................................47

7.5 First-out processing...............................................................................................47

8 Alarm display processing................................................................................................49

8.1 General .................................................................................................................49

8.2 Grouped alarms.....................................................................................................49

8.3 Alarm suppression.................................................................................................51

8.4 Dark-board presentation........................................................................................51

9 Alarm control and management ......................................................................................53

9.1 General .................................................................................................................53

9.2 Audible warning and silence ..................................................................................53

9.3 Flash and reflash...................................................................................................55

9.4 Acknowledgement .................................................................................................55

9.5 Ringback ...............................................................................................................55

9.6 Reset ....................................................................................................................57

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SIST EN 62241:2015
62241  IEC:2004 – 5 –

10 Alarm presentation and display-control integration .........................................................63

10.1 General .................................................................................................................63

10.2 Alarm fascia and tile..............................................................................................69

10.3 VDU alarm list display ...........................................................................................71

10.4 Audible annunciation .............................................................................................77

11 Reliability, testing, and maintainability............................................................................77

11.1 Reliability ..............................................................................................................77

11.2 Testing ..................................................................................................................77

11.3 Maintainability .......................................................................................................79

12 Alarm recording ..............................................................................................................79

13 Alarm response procedures (ARP) .................................................................................81

13.1 General .................................................................................................................81

13.2 Contents ...............................................................................................................81

13.3 Format ..................................................................................................................81

Annex A (informative) Problems of alarm system .................................................................83

Annex B (informative) Information sources for signals used to generate alarms ...................85

Annex C (informative) Examples of alarm processing logic and dynamic prioritisation..........87

Annex D (informative) Conceptual example of alarm grouping and categorisation................91

Annex E (informative) Material for the need of distinction between alarm and status

information............................................................................................................................95

Annex F (informative) Example of arrangement of alarm tiles...............................................97

Annex G (informative) Examples of Points to Consider in the Categorisation of Alarms........99

Figure 1 – Alarm system functional design elements.............................................................29

Figure 2 – Typical alarm control sequence............................................................................59

Figure 3 – Typical alarm control sequence for a grouped alarm ............................................61

Figure F.1 – A horizontal layout of alarm tiles for redundant components..............................97

Figure F.2 – A perpendicular layout of alarm tiles for a set of alarms with different

importance............................................................................................................................97

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SIST EN 62241:2015
62241  IEC:2004 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
MAIN CONTROL ROOM –
ALARM FUNCTIONS AND PRESENTATION
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

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 62241 has been prepared by subcommittee 45A: Instrumentation

and control 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/540/FDIS 45A/546/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 62241:2015
62241  IEC:2004 – 9 –

This International Standard supplements 4.6.4 of IEC 60964:1989 and therefore supersedes

the guidance given in A.4.6.4 of Annex A of IEC 60964.

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result 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.
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SIST EN 62241:2015
62241  IEC:2004 – 11 –
INTRODUCTION
Technical background, main issues and organisation of the standard

IEC 60964:1989 was developed to supply requirements relevant for the design of Control

Rooms (CR) of nuclear power plants. In this first edition of IEC 60964 which has been used

extensively within the nuclear industry, the subject of alarm systems was tackled in a one

page clause. Considering the return of experience gathered worldwide on the subject, it

appeared that a comprehensive standard on alarm systems was needed.

This standard is for application to the design of new main control rooms of nuclear power

plants conforming to IEC 60964, where work is initiated after the publication of this standard.

It serves as a reference for upgrading and modernizing existing control rooms. If it is desired

to apply it to supplementary and local control rooms, special attention should be given to

identifying the areas affected.

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

IEC 62241 will be directly referenced by the second edition of IEC 60964 (under consideration)

and is the third level document specifically tackling the topic of alarm systems.

For more details on the structure of the IEC SC 45A series of standards, see below the

“Description of the structure of the IEC SC 45A series of standards”.
Recommendations and limitations regarding the application of this standard

This Standard supplements Subclause 4.6.4 of IEC 60964:1989 and therefore supersedes the

guidance given in A.4.6.4 of Annex A of IEC 60964 Ed.1.0.

For the categorization of alarm systems, the safety classification of IEC 61226 should be

taken into account.

Description of the structure of the IEC SC 45A series of standards and relationships

with other IEC documents and other bodies documents (IAEA, ISO)

The top level document of the IEC SC 45A series of standards is IEC 61513. It provides

general requirements for instrumentation and control systems and equipment (I&C systems)

that are used to perform functions important to safety in nuclear power plants (NPPs).

IEC 61513 structures the IEC SC 45A series of standards.

IEC 61513 refers directly to other IEC SC 45A standards for general topics related to

categorization 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.
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SIST EN 62241:2015
62241  IEC:2004 – 13 –

A fourth level extending the IEC SC 45A series of standards corresponds to the Technical

Reports which are not normative.

IEC 61513 has adopted a presentation format similar to the basic safety series IEC 61508

with an overall safety life-cycle framework and a system life-cycle framework and provides an

interpretation of the general requirements of IEC 61508, parts 1, 2 and 4, for the nuclear

application sector. Compliance with this standard will facilitate consistency with the

requirements of IEC 61508 as they have been interpreted for the nuclear industry. 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 50-C-QA for topics related to quality assurance.

The IEC SC 45A series of standards consistently implements and details the principles and

basic safety aspects provided in the IAEA code on the safety of nuclear power plants and in

the IAEA safety series, in particular the Requirements NS-R-1 and the Safety Guide NS-G-

1.3 . The terminology and definitions used by IEC SC 45A standards are consistent with those

used by the IAEA.
———————
Requirements NS-R-1: Safety of Nuclear Power Plants: Design

Safety Guide NS-G-1.3: Instrumentation and Control Systems Important to Safety in Nuclear Power Plants

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SIST EN 62241:2015
62241  IEC:2004 – 15 –
NUCLEAR POWER PLANTS –
MAIN CONTROL ROOM –
ALARM FUNCTIONS AND PRESENTATION
1 Scope and object

This International Standard provides the functional requirements for the alarm systems in the

main control room of nuclear power plants. It gives definitions of the terms used for alarm

functions. It also establishes the human factors requirements and the design guidelines for

alarm presentation for the main control room of nuclear power plants.

NOTE The alarm functions can be implemented in a dedicated system (alarm system) or preferably be an

integrated part of the main control room HMI (Human-Machine Interface) system.

It specifies the alarm functions including those for the selection and definition of original alarm

signals, alarm signal processing (e.g., event sequence processing, static and dynamic

prioritisation), alarm display processing (e.g., alarm suppression) and the use of associated

display devices (e.g., Visual Display Unit (VDU), conventional alarm fascia, mural display),

with acknowledge and reset sequences, and other related matters.

Under abnormal conditions or plant transient conditions in the nuclear power plant, many

alarms occur simultaneously. For this reason, the alarm functions of the main control room of

nuclear power plants require special considerations for human factors engineering and

system configuration, to avoid operator misunderstandings and to provide the operator with

adequate information. Therefore, the scope includes special alarm functions based on human

factors for monitoring and operation of nuclear power plants. It does not cover specific alarm

systems, such as the fire alarm and security alarm systems.

The object of this Standard is to establish a common international understanding of the

underlying functional design basis of alarm systems for control rooms, covering the

corresponding functional requirements, the human factors requirements and design guidelines

for the alarm functions and alarm presentation for the main control room of nuclear power

plants.
This Standard therefore aims to give guidance to reduce problems which have been

experienced in the past: omission of important alarms, delay in detecting important alarms,

increased workload that may affect the performance of other operational activities, inattention

to frequently activated alarms known as ‘nuisance alarms,’ and confusion associated with the

misunderstanding of the relationships among alarms and of the importance of alarms.

2 Normative references

The following referenced documents are necessary 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.
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SIST EN 62241:2015
62241  IEC:2004 – 17 –
IEC 60964:1989, Design for control rooms of nuclear power plants

IEC 61226, Nuclear power plants – Instrumentation and control systems important for safety –

Classification

IEC 61771, Nuclear power plants – Main control room – Verification and validation of design

IEC 61772, Nuclear power plants – Main control room – Application of visual display units

(VDU)

IEC 61839, Nuclear power plants – Design of control rooms – Functional analysis and

assignments
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60964, as well as

the following definitions, apply.

NOTE When the same term is defined in IEC 60964 and in this standard, the definition given in this standard

applies.
3.1
alarm

item of diagnostic, prognostic, or guidance information, which is used to alert the operator and

to draw his or her attention to a process or system deviation

NOTE Specific information provided by alarms includes the existence of an anomaly for which corrective action

might be needed, the cause and potential consequences of the anomaly, the overall plant status, corrective action

to the anomaly, and feedback of corrective actions.
Two types of deviation may be recognised:
– unplanned – undesirable process deviations and equipment faults;

– planned – deviations in process conditions or equipment status that are the expected response to but could be

indicative of undesirable plant conditions.
3.2
alarm acknowledgement

action, which operators are required to carry out to show that they have recognized an alarm

presented to them
3.3
alarm avalanche

condition where a large number of alarms appear within a short time at a rate exceeding the

operator’s capacity to take them into account
3.4
alarm coding

method of highlighting an object of concern visually or audibly, with the intention of drawing

the operator’s attention to the object
3.5
alarm control

set of alarm presentation control functions, which support the operators in recognizing alarm

status correctly and in a timely manner

NOTE Alarm acknowledgement, silence, and reset are typical examples of alarm control.

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SIST EN 62241:2015
62241  IEC:2004 – 19 –
3.6
alarm display processing

alarm signal processing functions or mechanisms, which are used in controlling or enhancing

alarm presentation, for example, grouped alarms, alarm suppression
NOTE The a
...

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