oSIST prEN IEC 62705:2025

SLOVENSKI STANDARD
01-december-2025
Jedrski objekti - Merilna in nadzorna oprema za zagotavljanje varnosti - Sistemi za
nadzor sevanja (RMS) - Značilnosti in življenjski cikel
Nuclear facilities - Instrumentation and control important to safety - Radiation monitoring
systems (RMS): Characteristics and lifecycle
Kerntechnische Anlagen - Leittechnische Systeme mit sicherheitstechnischer Bedeutung
- Strahlungsüberwachungssysteme: Eigenschaften und Lebenszyklus
Installations nucléaires - Instrumentation et contrôle commande importants pour la
sûreté - Systèmes de surveillance des rayonnements (RMS): Caractéristiques et cycle
de vie
Ta slovenski standard je istoveten z: prEN IEC 62705:2025
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 DRAFT
prEN IEC 62705
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 27.120.20 -
English Version
Nuclear facilities - Instrumentation and control important to
safety - Radiation monitoring systems (RMS): Characteristics
and lifecycle
(IEC 62705:2022)
Installations nucléaires - Instrumentation et contrôle Kerntechnische Anlagen - Leittechnische Systeme mit
commande importants pour la sûreté - Systèmes de sicherheitstechnischer Bedeutung -
surveillance des rayonnements (RMS): Caractéristiques et Strahlungsüberwachungssysteme: Eigenschaften und
cycle de vie Lebenszyklus
(IEC 62705:2022) (IEC 62705:2022)
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2026-01-02.

The text of this draft consists of the text of IEC 62705:2022.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CENELEC 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,
Türkiye and the United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 82120 Ref. No. prEN IEC 62705:2025 E

European foreword
This document (prEN IEC 62705:2025) consists of the text of document IEC 62705:2022, prepared by
IEC/SC 45A “Instrumentation, control and electrical power systems of nuclear facilities” of IEC/TC 45
"Nuclear instrumentation".
This document is currently submitted to the Enquiry.
The following dates are proposed:
• latest date by which the existence of this document (doa) dav + 6 months
has to be announced at national level
• latest date by which this document has to be (dop) dav + 12 months
implemented at national level by publication of an
identical national standard or by endorsement
• latest date by which the national standards (dow) dav + 36 months
conflicting with this document have to be withdrawn (to be confirmed or
modified when voting)
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 document does not prevent Member States from taking more stringent nuclear
safety and/or security measures in the subject-matter covered by this document.
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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60532 - Radiation protection instrumentation - - -
Installed dose rate meters, warning
assemblies and monitors - X and gamma
radiation of energy between 50 keV and 7
MeV
IEC 60761-1 - Equipment for continuous monitoring of EN 60761-1 -
radioactivity in gaseous effluents - Part 1:
General requirements
IEC 60761-2 - Equipment for continuous monitoring of EN 60761-2 -
radioactivity in gaseous effluents - Part 2:
Specific requirements for radioactive
aerosol monitors including transuranic
aerosols
IEC 60761-3 - Equipment for continuous monitoring of EN 60761-3 -
radioactivity in gaseous effluents - Part 3:
Specific requirements for radioactive
noble gas monitors
IEC 60761-4 - Equipment for continuous monitoring of EN 60761-4 -
radioactivity in gaseous effluents - Part 4:
Specific requirements for radioactive
iodine monitors
IEC 60761-5 - Equipment for continuous monitoring of EN 60761-5 -
radioactivity in gaseous effluents - Part 5:
Specific requirements for tritium monitors
IEC 60768 - Nuclear power plants - Instrumentation - -
important to safety - Equipment for
continuous in-line or on-line monitoring of
radioactivity in process streams for normal
and incident conditions
IEC/IEEE 60780- 2016 Nuclear facilities - Electrical equipment EN 60780-323 2017
323 important to safety - Qualification
IEC 60861 - Equipment for monitoring of radionuclides EN 60861 -
in liquid effluents and surface waters
Publication Year Title EN/HD Year
IEC 60880 - Nuclear power plants - Instrumentation EN 60880 -
and control systems important to safety -
Software aspects for computer-based
systems performing category A functions
IEC 60951-1 2022 Nuclear facilities - Instrumentation - -
systems important to safety - Radiation
monitoring for accident and post-accident
conditions - Part 1: General requirements
IEC 60951-2 - Nuclear power plants - Instrumentation - -
important to safety - Radiation monitoring
for accident and post-accident conditions
- Part 2: Equipment for continuous off-line
monitoring of radioactivity in gaseous
effluents and ventilation air
IEC 60951-3 - Radiation monitoring equipment for - -
accident and post-accident conditions in
nuclear power plants. Part 3: High range
area gamma radiation dose rate
monitoring equipment
IEC 60951-4 - Centrales nucléaires de puissance - - -
Matériels de surveillance des
rayonnements pour les conditions
accidentelles et post-accidentelles.
Troisième partie: Ensembles de
surveillance locale du débit de dose de
rayonnement gamma à large gamme
IEC 60960 - Functional design criteria for a safety - -
parameter display system for nuclear
power stations
IEC/IEEE 60980- - Nuclear facilities - Equipment important to EN IEC/IEEE 60980-344 -
344 safety - Seismic qualification
IEC 60987 - Nuclear power plants - Instrumentation EN IEC 60987 -
and control important to safety - Hardware
requirements
IEC 61031 - Nuclear facilities - Instrumentation and EN IEC 61031 -
control systems - Design, location and
application criteria for installed area
gamma radiation dose rate monitoring
equipment for use during normal
operation and anticipated operational
occurrences
IEC 61226 2020 Nuclear power plants - Instrumentation, EN IEC 61226 2021
control and electrical power systems
important to safety - Categorization of
functions and classification of systems
IEC 61250 - Nuclear reactors - Instrumentation and - -
control systems important for safety -
Detection of leakage in coolant systems
IEC 61504 - Nuclear facilities - Instrumentation and - -
control systems important to safety -
Centralized systems for continuous
monitoring of radiation and/or levels of
radioactivity
Publication Year Title EN/HD Year
IEC 61513 2011 Nuclear power plants - Instrumentation EN 61513 2013
and control important to safety - General
requirements for systems
IEC 61559 series Radiation protection instrumentation in - -
nuclear facilities - Centralized systems for
continuous monitoring of radiation and/or
levels of radioactivity
IEC 62003 - Nuclear power plants - Instrumentation, EN IEC 62003 -
control and electrical power systems -
Requirements for electromagnetic
compatibility testing
IEC 62138 - Nuclear power plants - Instrumentation EN IEC 62138 -
and control systems important to safety -
Software aspects for computer-based
systems performing category B or C
functions
IEC 62302 - Radiation protection instrumentation - - -
Equipment for sampling and monitoring
radioactive noble gases
IEC 62303 - Radiation protection instrumentation - - -
Equipment for monitoring airborne tritium
IEC 62566 2012 Nuclear power plants - Instrumentation EN 62566 2014
and control important to safety -
Development of HDL-programmed
integrated circuits for systems performing
category A functions
IEC 62566-2 - Nuclear power plants - Instrumentation EN IEC 62566-2 -
and control important to safety -
Development of HDL-programmed
integrated circuits - Part 2: HDL-
programmed integrated circuits for
systems performing category B or C
functions
IEC 63147 2017 Criteria for accident monitoring - -
instrumentation for nuclear power
generating stations
ISO/IEC 17025 - General requirements for the competence EN ISO/IEC 17025 -
of testing and calibration laboratories
ISO 2889 - Sampling airborne radioactive materials - -
from the stacks and ducts of nuclear
facilities
ISO 4037-1 - Radiological protection - X and gamma EN ISO 4037-1 -
reference radiation for calibrating
dosemeters and doserate meters and for
determining their response as a function
of photon energy - Part 1: Radiation
characteristics and production methods
Publication Year Title EN/HD Year
ISO 4037-3 - Radiological protection - X and gamma EN ISO 4037-3 -
reference radiation for calibrating
dosemeters and doserate meters and for
determining their response as a function
of photon energy - Part 3: Calibration of
area and personal dosemeters and the
measurement of their response as a
function of energy and angle of incidence

IEC 62705 ®
Edition 2.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Nuclear facilities – Instrumentation and control important to safety – Radiation

monitoring systems (RMS): Characteristics and lifecycle

Installations nucléaires – Instrumentation et contrôle commande importants

pour la sûreté – Systèmes de surveillance des rayonnements (RMS):

Caractéristiques et cycle de vie

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-5936-8

– 2 – IEC 62705:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 11
4 Symbols and abbreviated terms . 15
5 RMS categorization and classification . 16
5.1 Function categorization for RMS . 16
5.2 System classification for RMS . 16
5.3 Criteria for identifying the plant-specific variables . 16
6 RMS detailed design and implementation . 16
6.1 General . 16
6.2 Radioactive noble gas off-line monitoring . 17
6.3 Radioactive aerosol off-line monitoring . 17
6.4 Radioactive iodine off-line monitoring . 17
6.5 Liquid off-line monitoring . 18
6.6 Tritium off-line monitoring . 18
6.7 On-line or in-line monitoring . 18
6.8 Area monitoring . 18
6.9 Centralized system . 18
6.10 Leak detection . 18
7 RMS integration and validation . 19
7.1 RMS integration . 19
7.2 RMS validation . 19
8 RMS installation . 19
9 RMS design modification . 19
10 RMS qualification . 19
10.1 General . 19
10.2 Environmental qualification . 20
10.3 Seismic qualification . 20
10.4 Electromagnetic interference. 20
11 Calibration . 20
11.1 General . 20
11.2 Periodical calibration and functional check . 20
11.2.1 General . 20
11.2.2 Calibration check after installation . 20
11.2.3 Functional check. 21
11.2.4 Countermeasures to loss of monitoring during calibration or functional
check . 21
11.3 Radiation calibration . 21
11.4 Calibration for other quantity . 21
11.5 Traceability . 21
Annex A (informative) Example of safety classification for RMS important to safety . 22
Annex B (informative) Relation between IEC 61513 system lifecycle and IEC 62705
requirements . 23

IEC 62705:2022 © IEC 2022 – 3 –
Bibliography . 24

Table 1 – Overview of the standards covering the domain of radiation monitoring . 7
Table A.1 – Example of safety classification for RMS important to safety . 22
Table B.1 – Relation between IEC 61513 system lifecycle and IEC 62705 requirements . 23

– 4 – IEC 62705:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR FACILITIES – INSTRUMENTATION AND CONTROL
IMPORTANT TO SAFETY – RADIATION MONITORING SYSTEMS (RMS):
CHARACTERISTICS AND LIFECYCLE
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.
IEC 62705 has been prepared by subcommittee 45A: Instrumentation, control and electrical
power systems of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation. It
is an International Standard.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Modification of the title.
b) To be consistent with the categorization of the accident condition.
c) To update the references to new standards published since the first edition.
d) To update the terms and definitions.

IEC 62705:2022 © IEC 2022 – 5 –
The text of this International Standard is based on the following documents:
Draft Report on voting
45A/1442/FDIS 45A/1451/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 62705:2022 © IEC 2022
INTRODUCTION
a) Technical background, main issues and organisation of the Standard
This IEC standard sets out the requirements for the lifecycle management of radiation
monitoring systems (RMS) installed in the nuclear facilities (e.g. nuclear power plants,
nuclear fuel storage and processing sites).
This document is applicable to the equipment of RMS and intended for use during normal
operations, anticipated operational occurrence (AOO), design basis accidents (DBA) and
design extension conditions (DEC) including severe accidents (SA).
The document is intended for use by operators of nuclear facilities (utilities), systems
evaluators and by licensors.
b) Situation of the current Standard in the structure of the IEC SC 45A standard series
IEC 62705 is the third level in the hierarchy of SC 45A standards. This document provides
guidance on the application of existing IEC/ISO standards covering design and qualification
of system and equipment for RMS. This document is an application supplement of
IEC 61513 as shown in Annex B, and it is not intended that this document limits the
application of other IEC 61513 requirements to RMS lifecycle.
For general requirements and guidance, the following standards provide requirements and
guidance for RMS. IEC 61513 is the first level standard of SC 45A standards, and provides
general requirements for I&C systems and equipment that are used to perform functions
important to safety in nuclear facilities. IEC 61226 provides the criteria for classification of
instrumentation and control functions. Most modern RMSs contain computer-based
equipment. Hence RMS should often be treated as computer-based system. So the following
standards required for computer-based system are generally applicable to RMS. IEC 60880
provides the software requirements for category A functions and IEC 62138 provides the
software requirements for Category B or C functions. IEC 60987 provides hardware design
requirements for computer-based systems. IEC 62566 provides the requirements for HDL-
Programmed Device (HPD) for systems performing category A functions. IEC 62645
provides security requirements for computer based I&C systems. For qualification testing,
the following SC 45A standards are applicable. IEC/IEEE 60780-323 provides guidance for
the environmental qualification and IEC/IEEE 60980-344 provides guidance for seismic
qualification for equipment performing category A or B functions. IEC 62003 provides the
requirements for electromagnetic compatibility testing. In addition, IEC 61250 specifies the
leak detection requirements by using RMS.
For radiation monitoring specific requirements, the following standards provide
requirements and guidance for RMS. The IEC 60951 series provides guidance on the design
and testing of radiation monitoring equipment used for anticipated operational occurrences
(AOO), design basis accidents (DBA) and design extension conditions (DEC) including
severe accident (SA). The IEC 60761 series provide requirements for equipment for
continuous off-line monitoring of radioactivity in gaseous effluent in normal conditions. Some
of the SC 45B standards (e.g. Gas offline: IEC 62302, Tritium: IEC 62303) are now replacing
the IEC 60761 series. IEC 60861 provides requirements for equipment continuous off-line
monitoring of radioactivity in liquid effluent in normal conditions. IEC 60768 provides
requirements for equipment for continuous in-line and on-line monitoring of radioactivity in
process stream in normal and incident conditions. IEC 61031 provides requirements for
equipment for area radiation monitor in normal conditions in conjunction with IEC 60532.
IEC 61504 provides requirements for centralized system for plant-wide radiation monitoring
in conjunction with the IEC 61559 series which specifies the requirements for centralized
system. If the centralized system is a part of the safety parameter display system, IEC 60960
provides the functional design criteria. ISO 2889 gives guidance on gas and particulate
sampling. The ISO 4037 series provides calibration methodology for radiation monitors.
The relationship between these various standards is given in Table 1.
IEC 63147/IEEE Std 497™ provides general guidance for accident monitoring
instrumentation. IEEE Std 497™ was directly adopted as a joint logo standard and a
technical report, IEC TR 63123, was prepared to discuss the application of the joint standard
within the IEC context.
IEC 62705:2022 © IEC 2022 – 7 –
The structure of this standard is adapted from the structure of IEC 63147/IEEE Std 497™,
and the technical requirements of this standard are consistent with the requirements given
in IEC 63147/IEEE Std 497™ together with the application guidance given in IEC TR 63123.
For more details on the structure of the IEC SC 45A standard series, see item d) of this
introduction.
Table 1 – Overview of the standards covering the domain of radiation monitoring
Developer ISO IEC
SC45A SC45B
Sampling Calibration Normal
Normal
Scope (Normal (Normal operation, DBA DEC
operation
operation) operation) AOO
Radioactive noble IEC 62302,
ISO 4037-1, IEC 60951-1,
gas off-line ISO 2889 N/A N/A IEC 60761-1,
ISO 4037-3 IEC 60951-2
monitoring IEC 60761-3
Radioactive
ISO 4037-1, IEC 60951-1, IEC 60761-1,
aerosol off-line ISO 2889 N/A N/A
ISO 4037-3 IEC 60951-2 IEC 60761-2
monitoring
Radioactive iodine ISO 4037-1, IEC 60951-1, IEC 60761-1,
ISO 2889 N/A N/A
off-line monitoring ISO 4037-3 IEC 60951-2 IEC 60761-4
Liquid off-line
N/A N/A N/A N/A N/A IEC 60861
monitoring
IEC 62303,
Tritium off-line
N/A N/A N/A N/A N/A IEC 60761-1,
monitoring
IEC 60761-5
On-line or in-line ISO 4037-1, IEC 60951-1,
N/A IEC 60768 N/A N/A
monitoring ISO 4037-3 IEC 60951-4
ISO 4037-1,
Area monitoring N/A IEC 61031 IEC 60951-1, IEC 60951-3 IEC 60532
ISO 4037-3
Centralized
N/A N/A IEC 61504, IEC 60960 N/A IEC 61559-1
system
IEC 61513, IEC 60880,
IEC 60987, IEC 61226,
Classification/basi
N/A N/A IEC 62138, IEC 62566, N/A N/A
c requirements
IEC 62566-2, IEC 62645,
IEC 61250
IEC/IEEE 60780-323,
Qualification N/A N/A IEC/IEEE 60980-344, N/A IEC 62706
IEC 62003
c) Recommendations and limitations regarding the application of this Standard
It is important to note that this document establishes no additional functional requirements
for systems important to safety. Where requirements are given in this standard, they refer
generally to the need to apply other IEC and ISO Standards and specific functional and
technical requirements contained in these standards.
To ensure that the document will continue to be relevant in future years, the emphasis has
been placed on issues of principle, rather than specific technologies.
d) Description of the structure of the IEC SC 45A standard series and relationships with
other IEC documents and other bodies documents (IAEA, ISO)
The IEC SC 45A standard series comprises a hierarchy of four levels. The top-level
documents of the IEC SC 45A standard series are IEC 61513 and IEC 63046.
IEC 61513 provides general requirements for instrumentation and control (I&C) systems and
equipment that are used to perform functions important to safety in nuclear power plants
(NPPs). IEC 63046 provides general requirements for electrical power systems of NPPs; it
covers power supply systems including the supply systems of the I&C systems.

– 8 – IEC 62705:2022 © IEC 2022
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
power systems for nuclear power plants.
IEC 61513 and IEC 63046 refer directly to other IEC SC 45A standards for general
requirements for specific topics, such as categorization of functions and classification of
systems, qualification, separation, defence against common cause failure, control room
design, electromagnetic compatibility, human factors engineering, 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 requirements for specific equipment, technical methods, or
activities. Usually these documents, which make reference to second-level documents for
general requirements, 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 (NPPs), the IAEA safety guide SSG-30 dealing with the safety
classification of structures, systems and components in NPPs, the IAEA safety guide SSG-
39 dealing with the design of instrumentation and control systems for NPPs, the IAEA safety
guide SSG-34 dealing with the design of electrical power systems for NPPs, the IAEA safety
guide SSG-51 dealing with human factors engineering in the design of NPPs and the
implementing guide NSS17 for computer security at nuclear facilities. The safety and
security terminology and definitions used by the 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 9001 as well as to IAEA GSR part 2 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, IEC 60964 is the entry document for the IEC/SC 45A control rooms standards,
IEC 63351 is the entry document for the human factors engineering standards and
IEC 62342 is the entry document for the 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 TR 64000 provides a more comprehensive description of the overall structure of the IEC SC 45A
standards series and of its relationship with other standards bodies and standards.

IEC 62705:2022 © IEC 2022 – 9 –
NUCLEAR FACILITIES – INSTRUMENTATION AND CONTROL
IMPORTANT TO SAFETY – RADIATION MONITORING SYSTEMS (RMS):
CHARACTERISTICS AND LIFECYCLE
1 Scope
This document gives requirements for the lifecycle management of radiation monitoring systems
(RMS) and gives guidance on the application of existing IEC standards covering the design and
qualification of systems and equipment.
The purpose of this document is to lay down requirements for the lifecycle management of
RMSs and give application guidance. This document is intended to be consistent with the latest
versions of International Standards dealing with radiation monitors, sampling of radioactive
materials, instruments calibration, hardware and software design, classification, and
qualification. Unless otherwise specified in this document, top level IEC SC 45A standard,
IEC 61513, and the second level IEC SC 45A standards apply to RMSs.
This document is applicable to RMSs installed in nuclear facilities intended for use during
normal operation, anticipated operational occurrences (AOO), design basis accidents (DBA)
and design extension conditions (DEC), including severe accidents (SA). The technical
guidance contained in this document applies to nuclear facilities, although the specific functions
of individual facilities are considered during the design and operational lifecycle of RMSs.
Laboratory analysis and associated sample extraction, which are essential to a complete
programme of effluent monitoring, and investigation for fuel removal are not in the scope of this
document.
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.
IEC 60532, Radiation protection instrumentation – Installed dose rate meters, warning
assemblies and monitors – X and gamma radiation of energy between 50 keV and 7 MeV
IEC 60761-1, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 1:
General requirements
IEC 60761-2, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 2:
Specific requirements for radioactive aerosol monitors including transuranic aerosols
IEC 60761-3, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 3:
Specific requirements for radioactive noble gas monitors
IEC 60761-4, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 4:
Specific requirements for radioactive iodine monitors
IEC 60761-5, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 5:
Specific requirements for tritium monitors

– 10 – IEC 62705:2022 © IEC 2022
IEC 60768, Nuclear power plants – Instrumentation important to safety – Equipment for
continuous in-line or on-line monitoring of radioactivity in process streams for normal and
incident conditions
IEC/IEEE 60780-323:2016, Nuclear facilities – Electrical equipment important to safety system
– Qualification
IEC 60861, Equipment for monitoring of radionuclides in liquid effluents and surface waters
IEC 60880, Nuclear power plants – Instrumentation and control systems important to safety –
Software aspects for computer-based systems performing category A functions
IEC 60951-1:2022, Nuclear power plants – Instrumentation important to safety – Radiation
monitoring for accident and post-accident conditions – Part 1: General requirements
IEC 60951-2, Nuclear power plants – Instrumentation important to safety – Radiation monitoring
for accident and post-accident conditions – Part 2: Equipment for continuous off-line monitoring
of radioactivity in gaseous effluents and ventilation air
IEC 60951-3, Nuclear power plants – Instrumentation important to safety – Radiation monitoring
for accident and post-accident conditions – Part 3: Equipment for continuous high range area
gamma monitoring
IEC 60951-4, Nuclear power plants – Instrumentation important to safety – Radiation monitoring
for accident and post-accident conditions – Part 4: Equipment for continuous in-line or on-line
monitoring of radioactivity in process streams
IEC 60960, Functional design criteria for a safety parameter display system for nuclear power
stations
IEC/IEEE 60980-344, Nuclear facilities – Equipment important to safety – Seismic qualification
IEC 60987, Nuclear power plants – Instrumentation and control important to safety – Hardware
requirements
IEC 61031, Nuclear facilities – Instrumentation and control systems – Design, location and
application criteria for installed area gamma radiation dose rate monitoring equipment for use
during normal operation and anticipated operational occurrences
IEC 61226:2020, Nuclear power plants – Instrumentation, control and electrical power systems
important to safety – Categorization of functions and classification of systems
IEC 61250, Nuclear reactors – Instrumentation and control systems important for safety –
Detection of leakage in coolant systems
IEC 61504, Nuclear facilities – Instrumentation and control systems important to safety –
Centralized systems for continuous monitoring of radiation and/or levels of radioactivity
IEC 61513:2011, Nuclear power plants – Instrumentation and control important to safety –
General requirements for systems
IEC 61559 (all parts), Radiation protection instrumentation in nuclear facilities – Centralized
systems for continuous monitoring of radiation and/or levels of radioactivity
IEC 62003, Nuclear power plants – Instrumentation, control and electrical power systems –
Requirements for electromagnetic compatibility testing

IEC 62705:2022 © IEC 2022 – 11 –
IEC 62138, Nuclear power plants – Instrumentation and control systems important to safety –
Software aspects for computer-based systems performing category B or C functions
IEC 62302, Radiation protection instrumentation – Equipment for sampling and monitoring
radioactive noble gases
IEC 62303, Radiation protection instrumentation – Equipment for monitoring airborne tritium
IEC 62566:2012, Nuclear power plants – Instrumentation and control important to safety –
Development of HDL-programmed integrated circuits for systems performing category A
functions
IEC 62566-2, Nuclear power plants – Instrumentation and control systems important to safety
– Development of HDL-programmed integrated circuits – Part 2: HDL-programmed integrated
circuits for systems performing category B or C functions
IEC 63147:2017/IEEE Std 497™, Criteria for accident monitoring instrumentation for nuclear
power generationg stations
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
ISO 2889, Sampling airborne radioactive materials from the stacks and ducts of nuclear
facilities
ISO 4037-1, Radiological protection – X and gamma reference radiation for calibrating
dosemeters and doserate meters and for determining their response as a function of photon
energy – Part 1: Radiation characteristics and production methods
ISO 4037-3, Radiological protection – X and gamma reference radiation for calibrating
dosemeters and doserate meters and for determining their response as a function of photon
energy – Part 3: Calibration of area and personal dosemeters and the measurement of their
response as a function of energy and angle of incidence
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
accident conditions
deviat
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