IEC 62705:2022

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
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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.
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The committee has decided that the contents of this document will remain unchanged until the
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specific document. At this date, the document will b
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