IEC 62397:2022

IEC 62397
®

Edition 2.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Nuclear power plants – Instrumentation and control important to safety –
Resistance temperature detectors

Centrales nucléaires de puissance – Instrumentation et contrôle-commande
importants pour la sûreté – Sondes à résistance

IEC 62397:2022-11(en-fr)

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IEC 62397

®


Edition 2.0 2022-11




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE











Nuclear power plants – Instrumentation and control important to safety –

Resistance temperature detectors



Centrales nucléaires de puissance – Instrumentation et contrôle-commande

importants pour la sûreté – Sondes à résistance

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.120.20 ISBN 978-2-8322-6045-6




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – IEC 62397:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions . 10
3.2 Abbreviated terms . 11
4 Design and construction requirements . 12
4.1 General . 12
4.2 Reliability . 12
4.3 Materials . 12
4.3.1 General . 12
4.3.2 Radiation dose to materials . 12
4.3.3 Resistance element material . 12
4.3.4 Seals and adhesives . 13
4.4 Connections . 13
4.4.1 Structural type . 13
4.4.2 Electrical connection . 14
4.4.3 Mechanical connection . 16
4.5 Manufacturing quality . 17
4.6 Ambient conditions (normal and accident operations) and qualification . 17
4.7 RTD performance. 18
4.7.1 General . 18
4.7.2 Accuracy . 18
4.7.3 Resistance temperature calibration . 18
4.7.4 Self-heating error . 19
4.7.5 Thermal response time . 19
4.7.6 Interchangeability . 20
4.7.7 Electrical insulation resistance . 20
4.7.8 Repeatability (thermal shock) . 20
4.7.9 Vibration . 20
4.7.10 Steam test . 21
4.7.11 Thermal cycling . 21
4.7.12 Dielectric inspection . 21
4.7.13 Hydraulic strength . 21
4.7.14 In situ response time testing . 21
4.8 Identification . 22
4.9 Failure mode and effects analysis . 22
5 Inspection and tests . 22
5.1 General . 22
5.2 Inspection and test failure . 23
5.3 Inspection and test reports . 23
5.4 Test method . 23
5.4.1 Assembly and appearance inspection . 23
5.4.2 Calibration procedure . 23
5.4.3 Self-heating test . 24

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IEC 62397:2022 © IEC 2022 – 3 –
5.4.4 Thermal response time . 24
5.4.5 Insulation resistance test . 24
5.4.6 Repeatability test (thermal shock) . 24
5.4.7 Vibration test . 24
5.4.8 Steam test . 25
5.4.9 Thermal cycling . 25
5.4.10 Dielectric inspection test . 25
5.4.11 Hydraulic test . 25
5.4.12 In situ response time test . 26
5.4.13 Cross-calibration testing . 26
5.5 Production test . 27
5.6 Qualification test . 28
6 Documentation . 29
Annex A (informative) In situ response time test methods . 31
A.1 Loop current step response test (LCSR) . 31
A.2 Calculation of the response time by temperature noise (passive method) . 34
A.3 Self-heating method (active method) . 36
A.4 Instructions for the application of test . 38
Bibliography . 39

Figure 1 – Form and dimensions of an RTD . 13
Figure 2 – Installation of a rigid RTD (Type I) . 14
Figure 3 – Installation of a rigid RTD (Type II) long insertion . 14
Figure 4 – Installation of a rigid RTD (Type II) short insertion . 14
Figure 5 – Type A of RTD connection . 16
Figure 6 – Type B of RTD connection . 16
Figure A.1 – LCSR and plunge transients . 33
Figure A.2 – Power spectrum density (PSD) plot of a sensor (smoothing of the power
spectrum) . 35
Figure A.3 – Power spectrum density (PSD) plot of a sensor (associated modal
response) . 36

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– 4 – IEC 62397:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL IMPORTANT TO SAFETY –
RESISTANCE TEMPERATURE DETECTORS

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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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 62397 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 2007; it also cancels
and replaces the first edition of IEC 61224:1993. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
1) The definitions, terms, references, test methods, test requirements and other contents in
IEC 61224 are incorporated into the corresponding clauses of IEC 62397, including the situ
response time test methods;
2) Move the second paragraph of Scope to 4.1 and add "certain design extension conditions"
in the text;
3) Add the definition of temperature units of ITS-90;

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IEC 62397:2022 © IEC 2022 – 5 –
4) Add reference standards, including IEC 60737:2010, IEC 60751:2022, IEC 62765-2:2019,
IEC 62342:2007, IEC 62385:2007, IEC 61298-2, IEC 60068-2;
5) Update the reference IEC 60780 to IEC/IEEE 60780-323:2016; update the reference
IEC 60980 to IEC/IEEE 60980-344:2020;
6) Delete the outdated definition of "accuracy (measurement)" and modify the definition of
"calibration", "drift" and "response time";
7) Add the terms and definitions of "cross-calibration (cross-validation)", "self-heating index",
"tolerance of RTD", "sheath", "in situ measurement", and some abbreviated terms (e.g.,
NPP);
8) Delete the reference values of failure rate, radiation dose, contact resistance and leak rate,
environmental conditions and test conditions in 4.2, 4.3.2, 4.4.2.2, 4.6, 5.4.7;
9) Clarify 4.3.1;
10) Add "fast neutron damage" and "β irradiation" in 4.3.2 and correct the requirement for
material change to be "shall not";
11) Replace platinum description with general material requirement in 4.3.3;
12) Delete the statement on sealant elements and flat sealants;
13) Add labels of dust cover, spring and extension tube in Figure 3 and Figure 4 and correct a
typo in Figure 6;
14) Add electrical connector configuration requirement referring to IEC 60751 in 4.4.2.1;
15) Modify the temperature rating requirement of type I connector in 4.4.2.2 and add the
definition of manufacturer in the footnote;
16) Add the type of connection for RTD mounted in pipe and relax the statement on spring
force in 4.4.3.1;
17) Modify the type I and type II statement in 4.4;
18) Change the subtitle to "Manufacturing Quality" and add detailed requirements in 4.5;
19) Considering the application for difference types of nuclear power plants, in 4.6 and 4.7
introduce the concept that the user shall specify the requirements, test method and
acceptance criteria for tests depending on the application of the subject RTD;
20) Delete the last three paragraphs in 4.6;
4.7 and move the test requirements to a new
21) Add detailed performance requirements in
subclause 5.4 "Test method";
22) Replace "330 °C" in the standard with the (highest) operating temperature;
23) Add a new subclause "4.7.1 General" to describe the general requirements and restate in
situ response time measurement requirement;
24) Add the Callendar formula for temperature range of -200 °C to 0 °C and delete the
temperature tolerance values and refer to IEC 60751 in 4.7.3;
25) Supplement detailed requirements of "self-heating error" in 4.7.4;
26) Change the subtitle to "thermal response time" in 4.7.5 and delete the definition of thermal
response time;
27) Relax the performance requirements to "should" in 4.7.8, 4.7.9, 4.7.10, 4.7.11 and 4.7.13,
and relax the steam test requirement to only RTDs used in steam environment;
28) Merge "Insulation resistance test after storage" into "Electrical insulation resistance",
reduce the requirement and change insulation resistance under 200 °C to be 10 MΩ in
4.7.7;
29) Add "Dielectric inspection" and "Hydraulic strength" as 4.7.12 and 4.7.13;
30) Revise description on in situ response time testing in 4.7.14;
31) Add identifications in 4.8;
32) Delete the insulation breakdown test;
33) Refer to IEC 60751 for self-heating test in 5.4.3;

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– 6 – IEC 62397:2022 © IEC 2022
34) Delete the vibration spectrum for vibration test, and refer to IEC 60068-2-6 in 5.4.7;
35) Revise thermal cycling test requirement to be more general and refer to IEC 60068-2-30 in
5.4.9;
36) Add 5.4.13 "Cross-calibration testing";
37) Add dielectric inspection test and hydraulic test as product tests in 5.5 and note that the
user can specify the test requirement;
38) Add dielectric inspection test and hydraulic test as qualification tests in 5.6, note that the
user can specify the test requirement, and refer to IEC/IEEE 60780-323 and
IEC/IEEE 60980-344 or pertinent national guides and regulations;
39) Change title from "Technical information required" to "Documentation" of Clause 6 and add
"the regular maintenance strategy" in performance specification;
40) Add an informative annex "Annex A In situ response time test methods" to include the
related information from IEC 61224, update figures and cross-references, and cite it in
4.7.13 and 5.4.12;
41) Add the IAEA documents in bibliography.
The text of this International Standard is based on the following documents:
Draft Report on voting
45A/1447/FDIS 45A/1454/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/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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IEC 62397:2022 © IEC 2022 – 7 –
INTRODUCTION
a) Technical background, main issues and organisation of the standard
This standard describes the requirements for the design, material selection, procurement,
construction, and testing of resistance temperature detectors (RTDs) used in nuclear power
plants (NPPs). These RTDs may be used in both the nuclear safety I&C systems and/or in the
non-safety-related instrumentation systems.
This standard is a revision merger of IEC 62397 and IEC 61224 and was initiated in November
2019.
b) Situation of the current standard in the structure of the SC 45A standard series
IEC 62397 is not directly referenced by IEC 61513 and is a third-level SC 45A document
tackling the issue of RTDs.
For more details on the structure of the SC 45A series of standards, see item d) of this
introduction.
c) Recommendations and limitations regarding the application of this standard
There is no particular recommendation or limitation regarding the application of this standard.
d) Description of the structure of the IEC SC45A 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.
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.

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– 8 – IEC 62397:2022 © IEC 2022
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 wel
...