IEC 62705:2022
(Main)Nuclear facilities - Instrumentation and control important to safety - Radiation monitoring systems (RMS): Characteristics and lifecycle
Nuclear facilities - Instrumentation and control important to safety - Radiation monitoring systems (RMS): Characteristics and lifecycle
IEC 62705:2022 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. 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). This second edition cancels and replaces the first edition published in 2014. This edition includes the following significant technical changes with respect to the previous edition:
- modification of the title.
- to be consistent with the categorization of the accident condition.
- to update the references to new standards published since the first edition.
- to update the terms and definitions.
Installations nucléaires - Instrumentation et contrôle-commande importants pour la sûreté - Systèmes de surveillance des rayonnements (RMS): Caractéristiques et cycle de vie
L'IEC 62705:2022 établit les exigences en matière de gestion du cycle de vie des systèmes de surveillance des rayonnements (RMS) et fournit des recommandations relatives à l'application des normes IEC existantes qui couvrent la conception et la qualification des systèmes et des matériels. Le présent document a pour objet d'établir les exigences en matière de gestion du cycle de vie des RMS et de fournir des recommandations d'application. Le présent document est destiné à être cohérent avec les dernières versions des Normes internationales relatives aux moniteurs de surveillance des rayonnements, à l'échantillonnage des matériaux radioactifs, à l'étalonnage des instruments, à la conception des matériels et logiciels, au classement et à la qualification des systèmes. Le présent document s'applique aux RMS installés dans les installations nucléaires et destinés à être utilisés pendant le fonctionnement normal, en cas d'incident de fonctionnement prévu (IFP), lors d'accidents de dimensionnement (DBA) et en conditions additionnelles de dimensionnement (DEC), incluant les accidents graves (SA). Cette deuxième édition annule et remplace la première édition parue en 2014. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- le titre a été modifié;
- la catégorisation des conditions accidentelles a été harmonisée;
- les références aux nouvelles normes publiées depuis la première édition ont été mises à jour;
- les termes et définitions ont été mis à jour.
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IEC 62705 ®
Edition 2.0 2022-11
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants facilities –
Instrumentation and control important to safety – Radiation monitoring
systems (RMS): Characteristics and lifecycle
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IEC 62705 ®
Edition 2.0 2022-11
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants facilities –
Instrumentation and control important to safety – Radiation monitoring
systems (RMS): Characteristics and lifecycle
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.120.20 ISBN 978-2-8322-6126-2
– 2 – IEC 62705:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 13
4 Symbols and abbreviated terms . 17
5 RMS categorization and classification . 18
5.1 Function categorization for RMS . 18
5.2 System classification for RMS . 18
5.3 Criteria for identifying the plant-specific variables . 18
6 RMS detailed design and implementation . 19
6.1 General . 19
6.2 Radioactive noble gas off-line monitoring . 19
6.3 Radioactive aerosol off-line monitoring . 19
6.4 Radioactive iodine off-line monitoring . 20
6.5 Liquid off-line monitoring . 20
6.6 Tritium off-line monitoring . 20
6.7 On-line or in-line monitoring . 20
6.8 Area monitoring . 20
6.9 Centralized system . 21
6.10 Leak detection . 21
7 RMS integration and validation . 21
7.1 RMS integration . 21
7.2 RMS validation . 21
8 RMS installation . 21
9 RMS design modification . 21
10 RMS qualification . 22
10.1 General . 22
10.2 Environmental qualification . 22
10.3 Seismic qualification . 22
10.4 Electromagnetic interference. 22
11 Calibration . 23
11.1 General . 23
11.2 Periodical calibration and functional check . 23
11.2.1 General . 23
11.2.2 Calibration check after installation . 23
11.2.3 Functional check. 23
11.2.4 Countermeasures to loss of monitoring during calibration or functional
check . 23
11.3 Radiation calibration . 23
11.4 Calibration for other quantity . 23
11.5 Traceability . 23
Annex A (informative) Example of safety classification for RMS important to safety . 24
Annex B (informative) Relation between IEC 61513 system lifecycle and IEC 62705
requirements . 25
Bibliography . 26
Table 1 – Overview of the standards covering the domain of radiation monitoring in
NPPs . 7
Table A.1 – Example of safety classification for RMS important to safety . 24
Table B.1 – Relation between IEC 61513 system lifecycle and IEC 62705 requirements . 25
– 4 – IEC 62705:2022 RLV © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS 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
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This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 62705:2014. A vertical bar appears in the margin wherever a change has
been made. Additions are in green text, deletions are in strikethrough red text.
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.
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.
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– 6 – IEC 62705:2022 RLV © 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 system (RMS) installed in the nuclear power plants (NPPs). This standard is
applicable to the equipment of RMS and intended to be used during normal operations and
anticipated operational occurrences, as well as, for certain monitors, in accident conditions.
This standard may be applicable to other nuclear facilities (e.g. nuclear fuel storage and
processing sites) by evaluating the differences from NPPs.
It is intended that the Standard be used by operators of NPPs (utilities), systems evaluators
and by licensors.
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 NPPs 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 accident and post-accident
conditions 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.
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 in NPPs
IEC
Developer ISO
SC 45A SC 45B
Accident and
Scope Sampling Calibration post accident Normal conditions
conditions
IEC 62302 /
Radioactive noble gas ISO 4037-1, IEC 60951-1,
ISO 2889 N/A IEC 60761-1,
off-line monitoring ISO 4037-3 IEC 60951-2
IEC 60761-3
Radioactive aerosol ISO 4037-1, IEC 60951-1, IEC 60761-1,
ISO 2889 N/A
off-line monitoring ISO 4037-3 IEC 60951-2 IEC 60761-2
Radioactive iodine off- ISO 4037-1, IEC 60951-1, IEC 60761-1,
ISO 2889 N/A
line monitoring ISO 4037-3 IEC 60951-2 IEC 60761-4
Liquid off-line
N/A N/A N/A N/A IEC 60861
monitoring
IEC 62303 /
Tritium off-line
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
monitoring ISO 4037-3 IEC 60951-4
ISO 4037-1, IEC 60951-1,
Area monitoring N/A IEC 61031 IEC 60532
ISO 4037-3 IEC 60951-3
Centralized system N/A N/A IEC 61504, IEC 60960 IEC 61559-1
IEC 61513, IEC 60880,
Classification/basic IEC 60987, IEC 61226,
N/A N/A N/A
requirements IEC 62138, IEC 62566,
IEC 62645, IEC 61250
IEC 60780, IEC 60980,
Qualification N/A N/A IEC 62706
IEC 62003
– 8 – IEC 62705:2022 RLV © IEC 2022
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
For more details on the structure of the IEC SC 45A standard series, see item d) of this
introduction.
c) Recommendations and limitations regarding the application of this Standard
It is important to note that this document establishes no additional functional requirements
for safety 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 top-level document of the IEC SC 45A standard series is IEC 61513. It provides general
requirements for I&C systems and equipment that are used to perform functions important
to safety in NPPs. IEC 61513 structures the IEC SC 45A standard series.
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.
A fourth level extending the IEC SC 45A standard series, corresponds to the Technical
Reports which are not normative.
IEC 61513 has adopted a presentation format similar to the basic safety publication
IEC 61508 with an overall safety life-cycle framework and a system life-cycle framework.
Regarding nuclear safety, it provides the interpretation of the general requirements of
IEC 61508-1, IEC 61508-2 and IEC 61508-4, for the nuclear application sector, regarding
nuclear safety. 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 GS-R-3 and IAEA
GS-G-3.1 and IAEA GS-G-3.5 for topics related to quality assurance (QA).
The IEC SC 45A standards series consistently implements and details the principles and
basic safety aspects provided in the IAEA code on the safety of NPPs and in the IAEA safety
series, in particular the Requirements NS-R-1, establishing safety requirements related to
the design of Nuclear Power Plants, and the Safety Guide NS-G-1.3 dealing with
instrumentation and control systems important to safety in Nuclear Power Plants. The
terminology and definitions used by SC 45A standards are consistent with those used by
the IAEA.
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.
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
– 10 – IEC 62705:2022 RLV © IEC 2022
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, that are based on the requirements of a standard such as IEC 61508.
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.
NUCLEAR POWER PLANTS FACILITIES –
INSTRUMENTATION AND CONTROL IMPORTANT TO SAFETY –
RADIATION MONITORING SYSTEMS (RMS):
CHARACTERISTICS AND LIFECYCLE
1 Scope
This International Standard applies to radiation monitoring system (RMS) installed in the
nuclear power plants (NPPs). 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.
This International Standard is applicable to RMSs intended to be used during normal operations
and anticipated operational occurrences, and to be used during and/or after accident conditions.
The technical guidance contained in this Standard applies to NPPs, although the specific
functions of individual facilities shall be considered during the design and operational lifecycle
of RMS. 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 standard may be applicable to other nuclear facilities (e.g. nuclear fuel storage and
processing sites) by evaluating the differences from NPPs.
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
– 12 – IEC 62705:2022 RLV © IEC 2022
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
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 60780:1998, Nuclear power plants – Electrical equipment of the safety system –
Qualification
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 60980, Recommended practices for Seismic qualification of electrical equipment of the
safety system for nuclear generating 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
design requirements for computer-based systems
IEC 61031, Nuclear facilities – Instrumentation and control systems – Design, location and
application criteria for installed area gamma radiation dose rate monitoring equipment for use
in nuclear power plants during normal operation and anticipated operational occurrences
IEC 61226:20092020, Nuclear power plants – Instrumentation and control important to safety –
Classification of instrumentation and control functions 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 power plants facilities – Instrumentation and control systems important to
safety – Plant-wide radiation monitoring 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 and control important to safety
Instrumentation, control and electrical power systems – Requirements for electromagnetic
compatibility testing
IEC 62138, Nuclear power plants – Instrumentation and control systems important for 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
– 14 – IEC 62705:2022 RLV © IEC 2022
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
deviations from normal operation that are less frequent and more severe than anticipated
operational occurrences described by the following figure
Note 1 to entry: Accident conditions comprise design basis accidents and design extension conditions.
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.2
alarm assembly
assembly which is initiated by the processing assembly, and provides audible and/or visual
alarms, normally local to detector assembly
3.3
anticipated operational occurrence
AOO
deviation of an operational process from normal operation that is expected to occur at least
once during the operating lifetime of a facility but which, in view of appropriate design
provisions, does not cause any significant damage to items important to safety or lead to
accident conditions
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.4
calibration
set of operations that establish, under specified conditions the relationship between values of
quantities indicated by a measuring instrument or a measuring system, or values represented
by a material measure or a reference material, and the corresponding values realized by
standards
[SOURCE: IEC 62397:2007, 3.2]
3.5
category of an I&C function
one of three possible safety assignments (A, B, C) of I&C functions resulting from
considerations of the safety relevance of the function to be performed. An unclassified
assignment may be made if the function has no importance to safety
[SOURCE: IEC 61513:2011, 3.4]
3.6
centralized system
centralizer
central processing and control system for the calculation, display, and storage of data from the
processing assembly
3.7
class of an I&C system
one of three possible assignments (1, 2, 3) of I&C systems important to safety resulting from
consideration of their requirement to implement I&C functions of different safety importance. An
unclassified assignment is made if the I&C system does not implement functions important to
safety
[SOURCE: IEC 61513:2011, 3.6]
3.8
decision threshold
value of the estimator of the measurand, which, when exceeded by the result of an actual
measurement using a given measurement procedure of a measurand quantifying a physical
effect, is used to decide that the physical effect is present
Note 1 to entry: The decision threshold is defined such that in cases where the measurement result, y, exceeds the
decision threshold, y*, the probability of a wrong decision, namely that the true value of the measurand is not zero if
in fact it is zero, is less or equal to a chosen probability α.
Note 2 to entry: If the result, y, is below the decision threshold, y*, it is decided to conclude that the result cannot
be attributed to the physical effect; nevertheless, it cannot be concluded that it is absent.
[SOURCE: ISO 11929-1:2019, 3.12]
3.9
design basis accident
DBA
a postulated accident leading to accident conditions for which a facility is designed in
accordance with established design criteria and conservative methodology, and for which
releases of radioactive material are kept within acceptable limits
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.10
design extension conditions
DEC
postulated accident conditions that are not considered for design basis accidents, but that are
considered in the design process of the facility in accordance with best estimate methodology,
and for which releases of radioactive material are kept within acceptable limits
Note 1 to entry: Design extension conditions comprise conditions in events without significant fuel degradation and
conditions in events with melting of the reactor core including severe accident.
[SOURCE: IAEA Safety Glossary, 2018 edition]
– 16 – IEC 62705:2022 RLV © IEC 2022
3.11
detection limit
smallest true value of the measurand w
...
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
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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
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
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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
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indispensable for the correct application of this publication.
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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.
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.
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.
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 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
deviations from normal operation that are less frequent and more severe than anticipated
operational occurrences described by the following figure
– 12 – IEC 62705:2022 © IEC 2022
Note 1 to entry: Accident conditions comprise design basis accidents and design extension conditions.
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.2
alarm assembly
assembly which is initiated by the processing assembly, and provides audible and/or visual
alarms, normally local to detector assembly
3.3
anticipated operational occurrence
AOO
deviation of an operational process from normal operation that is expected to occur at least
once during the operating lifetime of a facility but which, in view of appropriate design
provisions, does not cause any significant damage to items important to safety or lead to
accident conditions
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.4
calibration
set of operations that establish, under specified conditions the relationship between values of
quantities indicated by a measuring instrument or a measuring system, or values represented
by a material measure or a reference material, and the corresponding values realized by
standards
[SOURCE: IEC 62397:2007, 3.2]
3.5
category of an I&C function
one of three possible safety assignments (A, B, C) of I&C functions resulting from
considerations of the safety relevance of the function to be performed. An unclassified
assignment may be made if the function has no importance to safety
[SOURCE: IEC 61513:2011, 3.4]
3.6
centralized system
centralizer
central processing and control system for the calculation, display, and storage of data from the
processing assembly
3.7
class of an I&C system
one of three possible assignments (1, 2, 3) of I&C systems important to safety resulting from
consideration of their requirement to implement I&C functions of different safety importance. An
unclassified assignment is made if the I&C system does not implement functions important to
safety
[SOURCE: IEC 61513:2011, 3.6]
3.8
decision threshold
value of the estimator of the measurand, which, when exceeded by the result of an actual
measurement using a given measurement procedure of a measurand quantifying a physical
effect, is used to decide that the physical effect is present
Note 1 to entry: The decision threshold is defined such that in cases where the measurement result, y, exceeds the
decision threshold, y*, the probability of a wrong decision, namely that the true value of the measurand is not zero if
in fact it is zero, is less or equal to a chosen probability α.
Note 2 to entry: If the result, y, is below the decision threshold, y*, it is decided to conclude that the result cannot
be attributed to the physical effect; nevertheless, it cannot be concluded that it is absent.
[SOURCE: ISO 11929-1:2019, 3.12]
3.9
design basis accident
DBA
a postulated accident leading to accident conditions for which a facility is designed in
accordance with established design criteria and conservative methodology, and for which
releases of radioactive material are kept within acceptable limits
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.10
design extension conditions
DEC
postulated accident conditions that are not considered for design basis accidents, but that are
considered in the design process of the facility in accordance with best estimate methodology,
and for which releases of radioactive material are kept within acceptable limits
Note 1 to entry: Design extension conditions comprise conditions in events without significant fuel degradation and
conditions in events with melting of the reactor core including severe accident.
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.11
detection limit
smallest true value of the measurand which ensures a specified probability of being detectable
by the measurement procedure
Note 1 to entry: With the decision threshold according to 3.8, the detection limit is the smallest true value of the
measurand for which the probability of wrongly deciding that the true value of the measurand is zero is equal to a
specified value, β, when, in fact, the true value of the measurand is not zero. The probability of being detectable is
consequently (1-β).
Note 2 to entry: The terms detection limit and decision threshold are used in an ambiguous way in different
standards (e.g. standards related to chemical analysis or quality assurance). If these terms are referred to one has
to state according to which standard they are used.
[SOURCE: ISO 11929-1:2019, 3.13]
– 14 – IEC 62705:2022 © IEC 2022
3.12
detector assembly
detector and associated electronics (amplifier, discriminator, output pulse shaper), and can also
include hydraulic and programmable electronic circuits
3.13
hardware description language
HDL
language used to formally describe the functions and/or the structure of an electronic
component for documentation, simulation or synthesis
Note 1 to entry: The most widely used HDLs are VHDL (IEEE 1076) and Verilog (IEEE 1364).
[SOURCE: IEC 62566:2012, 3.6]
3.14
HDL-Programmed Device
HPD
integrated circuit configured (for NPP I&C systems), with Hardware Description Languages and
related software tools
Note 1 to entry: HDLs and related tools (e.g. simulator, synthesizer) are used to implement the requirements in a
proper assembly of pre-developed micro-electronic technologies.
Note 2 to entry: The development of HPDs can use Pre-Developed Blocks.
Note 3 to entry: HPDs are typically based on blank FPGAs (Field Programmable gate Arrays) or similar micro-
electronic technologies.
[SOURCE: IEC 62566:2012, 3.7]
3.15
in-line monitoring
monitoring of the radioactivity in fluid by the detector located directly in the process stream
(pipe, stack, duct, etc.)
3.16
monitoring assembly
combinations of processing, alarm, and detector assemblies
3.17
network equipment
equipment supporting communication among assemblies of RMS and external equipment
3.18
off-line monitoring
monitoring of the activity in fluid by sample drawn from the process stream to the detector
located at some distance
3.19
on-line monitoring
monitoring of the radioactivity in fluid by the detector directly facing the process stream
3.20
processing assembly
assembly which converts the output signal from the detector assemblies into a form, generally
digital, suitable for transmission down a data link to the central computer, centralized system,
and/or which generates alarm outputs to the alarm units at present signal levels
3.21
radiation monitor
device designed to measure the level of ionizing radiation and able to emit a warning signal
Note 1 to entry: A radiation monitor may also provide quantitative information.
3.22
sampling assembly
set of interconnected instruments (devices) for collecting a representative sample
[SOURCE: IEC 60951-1:2022, 3.23]
3.23
severe accident
SA
accident more severe than a design basis accident and involving significant core degradation
[SOURCE: IAEA Safety Glossary, 2018 edition]
3.24
volu
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