ISO 20890-4:2020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 20890-4
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 4:
2020-05-15
Visual testing
Lignes directrices pour les contrôles périodiques des composants du
circuit primaire des réacteurs à eau légère —
Partie 4: Examen visuel
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 20890-4:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 20890-4:2020(E)

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© ISO 2020
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ISO/FDIS 20890-4:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Inspection technique. 4
5 Requirements . 4
5.1 Test personnel . 4
5.1.1 Task of NDT personnel . . 4
5.1.2 Personnel requirements . 4
5.2 Test area . 6
5.3 Optical auxiliaries and combined device system . 6
5.3.1 General. 6
5.3.2 Image quality and resolution . 6
5.3.3 Construction . 7
5.3.4 Lighting equipment for the remote visual testing . 8
5.3.5 Data storage medium . 8
5.3.6 Test robots . 8
6 Testing . 8
6.1 Preparation . 8
6.1.1 General. 8
6.1.2 Test location . 9
6.2 Performance . 9
6.2.1 General. 9
6.2.2 Direct visual testing . .10
6.2.3 Remote visual testing .10
6.2.4 Mechanized visual testing .10
6.3 Evaluation .10
6.4 Final measures .10
7 Recording .11
Annex A (informative) Examples of a test image.12
Annex B (informative) Test procedures .13
Bibliography .14
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ISO/FDIS 20890-4:2020(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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: 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 20890-4:2020(E)
Guidelines for in-service inspections for primary coolant
circuit components of light water reactors —
Part 4:
Visual testing
1 Scope
This document gives guidelines for pre-service inspection (PSI) and in-service inspections (ISI) for
reactor coolant circuit components of light water reactors and their installations as direct or remote
visual testing in the form of a
— general visual testing (overview), or
— selective visual testing (specific properties).
This document is also applicable to other components of nuclear installations. The requirements in this
document focuses on remote (mechanized) visual testing, but also specifies global requirements for
direct visual testing. For specific requirements for direct visual testing of welds see ISO 17637.
This document is not applicable to tests in respect to the general state that are carried out in conjunction
with pressure and leak tests and regular plant inspections.
This document specifies test methods that allow deviations from the expected state to be recognised,
requirements for the equipment technology and test personnel, the preparation and performance of the
testing as well as the recording.
NOTE Data concerning the test section, test extent, inspection period, inspection interval and evaluation of
indications is defined in the applicable national nuclear safety standards.
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 9712:2012, Non-destructive testing — Qualification and certification of NDT personnel
ISO 18490, Non-destructive testing — Evaluation of vision acuity of NDT personnel
EN 1330-10, Non-destructive testing — Terminology — Part 10: Terms used in visual testing
EN 13018, Non-destructive testing — Visual testing — General principles
EN 13927, Non-destructive testing — Visual testing — Equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1330-10 and the following apply.
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ISO/FDIS 20890-4:2020(E)

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
conspicuous indications
deviations in the actual state recorded during the visual testing from the expected target state
3.2
relevant indication
NDT indication (conspicuous indication) that is caused by condition or type of
discontinuity that requires evaluation
[SOURCE: ISO/TS 18173:2005, 2.24]
3.3
colour intensity
difference in a colour from the equally bright achromatic colour
Note 1 to entry: Colours with equally bright achromatic colour create the same grey tone in the black-white
appearance.
3.4
hue
chromatic and achromatic type of a colour
Note 1 to entry: Words like red, yellow, green etc. are used to refer to this in daily life.
Note 2 to entry: In this document achromatic colours means black and white and any type of grey.
3.5
data storage medium
storage medium for the storage of image information
3.6
direct visual testing
visual testing where there is an uninterrupted optical path from the observer's eye to the test area
Note 1 to entry: This test can be carried out with or without auxiliaries, e.g. magnifying glass, mirror, binoculars,
borescopes, endoscopes or fibre-optics.
[SOURCE: EN 1330-10:2003, 2.12, modified — The examples given in the Note are different.]
3.7
remote visual testing
visual testing where there is an interrupted optical path from the observer's eye to the test area
Note 1 to entry: Remote visual testing may include a device system that records, communicates, visualises and, if
necessary, stores image information.
[SOURCE: EN 1330-10:2003, 2.37, modified — Different systems are named in the Note.]
3.8
general visual testing
visual testing over areas of the component (3.10) to observe overall condition, integrity and state of
degradation
[SOURCE: EN 1330-10: 2003, 2.18]
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ISO/FDIS 20890-4:2020(E)

3.9
selective visual testing
local visual testing for unique recognition of specified properties
Note 1 to entry: The selective visual testing is used in order to record the state of parts, components (3.10) or
surfaces to be examined in respect to cracks, wear, corrosion, erosion or mechanical damage on the surface of the
parts or components (3.10).
3.10
component
part of a system delimited according to structural or functional aspects, which can still implement
independent sub-functions
3.11
reference standard
specimen for inspecting the settings of the test system and its function during the testing
Note 1 to entry: Test images (e.g. colour boards according to Annex A or similar test images) are used as reference
standards during the visual testing. Depending on the test assignment and device system, a scalability of test
images can be necessary.
3.12
mechanized visual testing
remote visual testing (3.8) with mechanized guidance of camera or video-endoscope
3.13
test section
part of the test area (3.15)
3.14
test supervisor
responsible for application of the test method and for the individual details of the test performance
including monitoring of the activities for preparation and performance of the test as well as analysis of
the test results
3.15
test area
defined area on the test object (3.17) over which the tests are to be conducted
[SOURCE: ISO 5577:2017, 6.2.2]
3.16
test surface
surface of the test object (3.17) to be tested
3.17
test object
part of a component (3.10) to be tested
3.18
visual testing
method of non-destructive testing using electromagnetic radiation in the optical range
[SOURCE: EN 1330-10:2003, 2.53]
Note 1 to entry: The visual testing serves to acquire the actual state of a test object with the human eye for
comparison with the expected target state.
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ISO/FDIS 20890-4:2020(E)

3.19
reference block
piece of material, with specified metallurgical, geometrical and dimensional characteristics, used for
calibration and assessment of equipment for visual testing
Note 1 to entry: Specified metallurgical, geometrical and dimensional characteristics means for example
material, weld seam implementation, form, wall thickness, any cladding present) with reference characteristics
(e.g. grooves, bores) that are adapted to the test assignment.
Note 2 to entry: Depending on the test assignment, the properties relevant to the inspection technique can be
determined by hue (3.4), colour intensity (3.3), reflectivity or texture of the surface.
4 Inspection technique
Visual testing is used to recognise deviations from the expected state. This state is specified in the test
procedures. Depending on the test assignment, the visual testing is conducted either as a general visual
testing or a selective visual testing. Depending on the accessibility and required detail recognition,
direct or remote visual testing is used, whereby the latter can be carried out as a mechanized visual
testing. The local radiation dose rate shall be considered when selecting the inspection techniques and
auxiliaries.
The suitability of the inspection technique and the combined device system shall be validated according
to the requirements of the applicable nuclear safety standards.
NOTE 1 The procedure for the qualification of the inspection techniques or the combined device system is
[3]
described in ENIQ report nr. 31 .
NOTE 2 The visual testing test method discussed in this document involves a standardized test method whose
application is realised based on standard test procedures relating to nuclear power plants. A qualification as
above can be necessary in individual cases if there are significant deviations from the specifications from the
test procedures.
A general test procedure shall be prepared. Annex B contains the items of the general test procedure.
5 Requirements
5.1 Test personnel
5.1.1 Task of NDT personnel
[4]
NDT personnel have a great responsibility, not only with respect to their employers or contractors
but also under the rules of good workmanship. The NDT personnel shall be independent and free from
economic influences with regard to his test results, otherwise the results may be compromised. The
NDT personnel shall be aware of the importance of his signature and the consequences of incorrect
test results for safety, health and environment. Under legal aspects, the falsification of certificates is an
offence and judged according to the national legal regulations. A tester may find himself in a conflicting
situation about his findings with his employer, the responsible authorities or legal requirements.
Finally, the NDT personnel is responsible for all interpretations of test results carrying his signature.
NDT personnel should never sign test reports beyond their certification (see Table 1).
NOTE For reasons of readability, the male form is used with personal names, however the female form is
also always intended.
5.1.2 Personnel requirements
The test personnel comprise the test inspector, the test supervisor and possibly the operating personnel
for the test robot.
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ISO/FDIS 20890-4:2020(E)

Those personnel, using qualified non-destructive testing (NDT) procedures and equipment, should be
qualified through one or any combination of the following:
— certification through a national NDT personnel certification scheme;
— theoretical and/or open trials;
— blind trials.
Any personnel certification requirements invok
...