ISO 20890-3:2020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 20890-3
ISO/TC 85/SC 6
Guidelines for in-service inspections
Secretariat: DIN
for primary coolant circuit
Voting begins on:
2020-03-20 components of light water reactors —
Voting terminates on:
Part 3:
2020-05-15
Hydrostatic testing
Lignes directrices pour les contrôles périodiques des composants du
circuit primaire des réacteurs à eau légère —
Partie 3: Essais de pression
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BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 20890-3:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
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©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 20890-3:2020(E)

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© ISO 2020
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ISO/FDIS 20890-3:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test system . 2
4.1 General . 2
4.2 Standard system . 2
5 Requirements . 2
5.1 Personnel requirements . 2
5.2 Test object . 3
5.3 Measuring equipment . 3
5.3.1 General. 3
5.3.2 Pressure measurement of the operating instructions . 3
5.3.3 Test manometer . 4
5.3.4 Temperature measurement . 4
5.4 Pressure generation system . 4
6 Testing . 4
6.1 Preparations . 4
6.2 Performance . 5
6.3 Final measures . 5
7 Test report . 5
Annex A (informative) Standard test procedures . 7
Bibliography . 8
© ISO 2020 – All rights reserved iii

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ISO/FDIS 20890-3:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by ISO/TC 85, Nuclear energy, nuclear technologies, and radiological
protection, Subcommittee SC 6, Reactor technology.
A list of all parts in the ISO 20890 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 20890-3:2020(E)
Guidelines for in-service inspections for primary coolant
circuit components of light water reactors —
Part 3:
Hydrostatic testing
1 Scope
This document gives guidelines for in-service system pressure tests of the reactor coolant circuit of
light water reactors.
This document specifies the test technique, the requirements for measuring equipment and additional
devices, the preparation and performance of the test as well as the recording and documentation, for
the purpose to ensure the reliability and comparability of tests.
NOTE Data on (test) pressure, (test) temperature, scope of testing, rates of change of pressure and
temperature, test schedule and inspection intervals can be obtained from the applicable national nuclear codes.
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.
ISO 8596, Ophthalmic optics — Visual acuity testing — Standard and clinical optotypes and their
presentation
ISO 18490, Non-destructive testing — Evaluation of vision acuity of NDT personnel
EN 837-2, Pressure gauges — Part 2: Selection and installation recommendations for pressure gauges
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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
test medium
reactor coolant or deionate
3.2
test temperature
temperature to which the pressure-retaining boundaries of the reactor coolant system and the test
medium (3.1) are to be heated
3.3
test pressure
overpressure to which the reactor coolant system is exposed during the test
© ISO 2020 – All rights reserved 1

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ISO/FDIS 20890-3:2020(E)

3.4
maximum operating pressure
design pressure
overpressure for which the reactor coolant system is designed with regard to safety, operational and
constructional requirements
4 Test system
4.1 General
The system pressure test provides a global statement of integrity regarding the reactor coolant system
and, as a safety measure for monitoring the consequences of alleged operationally induced damage
mechanisms, is a part of the concept for assuring component integrity during operation.
A general test procedure shall be prepared. Annex A contains the items of the general test procedure.
4.2 Standard system
The system pressure test is an integral test covering pressure-retaining components of the reactor
coolant system. After filling the reactor coolant system with the test medium, the system is pressurised
in accordance with a pressure-temperature-schedule to the test pressure, which shall be applied
continuously during a defined holding time. The pressure is the
...