ISO 20890-1:2020

INTERNATIONAL ISO
STANDARD 20890-1
First edition
2020-06
Guidelines for in-service inspections
for primary coolant circuit
components of light water reactors —
Part 1:
Mechanized ultrasonic testing
Lignes directrices pour les contrôles périodiques des composants du
circuit primaire des réacteurs à eau légère —
Partie 1: Contrôle mécanique par ultrasons
Reference number
©
ISO 2020
© ISO 2020
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Test systems . 7
4.1 Preliminary remark . 7
4.2 General . 7
4.3 Validation and localisation of reflectors. 8
4.3.1 Pulse-echo technique (PE technique) . 8
4.3.2 Transmitter-Receiver technique (TR-technique) . 8
4.3.3 Tandem technique . 8
4.3.4 Inspection technique with mode conversion . 8
4.3.5 V-transmission technique . 9
4.3.6 Phased-Array technique (PA). 9
4.3.7 Preferred angles of incidence and wave modes for search techniques . 9
5 Requirements .10
5.1 Test personnel .10
5.1.1 Task of NDT personnel . .10
5.1.2 Personnel requirements .10
5.2 Test object .11
5.3 Ultrasonic test equipment .11
5.3.1 Preliminary remark .11
5.3.2 Test robot .11
5.3.3 Ultrasonic test device .12
5.3.4 Data acquisition and analysis .13
5.3.5 UT probe .13
5.3.6 UT probe holders .15
5.3.7 UT probe cable (ultrasonic cable) .16
5.4 Couplant .16
5.5 Reference reflectors .16
5.6 Calibration block and reference or test block .17
5.7 Data storage medium .17
6 Testing .17
6.1 Preparation .17
6.1.1 General.17
6.1.2 Probe data sheets .17
6.1.3 Probe system .17
6.1.4 Test robot .18
6.1.5 Ultrasonic test device .18
6.1.6 Setting the test level .18
6.1.7 Data acquisition system (DAS) .19
6.1.8 Ultrasonic test equipment .19
6.2 Implementation .19
6.3 Visualisation of the digitized and saved measuring data .20
6.4 Analysis of indications .20
6.5 Final measures .20
7 Recording .21
7.1 Recording the setup for the ultrasonic test equipment .21
7.2 Test record and test report .21
7.3 Indication list .21
7.4 Findings record .22
Annex A (informative) Examples of test systems and transceiver probe arrangements .23
Annex B (informative) Forms .25
Annex C (informative) Findings record .28
Annex D (informative) Amplification compensation .29
Annex E (informative) Standard test procedures and test specifications .32
Bibliography .33
iv © ISO 2020 – All rights reserved

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 of 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 www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee 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.
INTERNATIONAL STANDARD ISO 20890-1:2020(E)
Guidelines for in-service inspections for primary coolant
circuit components of light water reactors —
Part 1:
Mechanized ultrasonic testing
1 Scope
This document gives guidelines for pre-service-inspections (PSI) and in-service inspections (ISI) with
mechanized ultrasonic test (UT) devices on components of the reactor coolant circuit of light water
reactors. This document is also applicable on other components of nuclear installations.
Mechanized ultrasonic inspections are carried out in order to enable an evaluation in case of
— fault indications (e.g. on austenitic weld seams or complex geometry),
— indications due to geometry (e.g. in case of root concavity),
— complex geometries (e.g. fitting weld seams), or
— if a reduction in the radiation exposure of the test personnel can be attained in this way.
Ultrasonic test methods are defined for the validation of discontinuities (volume or surface open),
requirements for the ultrasonic test equipment, for the preparation of test and device systems, for the
implementation of the test and for the recording.
This document is applicable for the detection of indications by UT using normal-beam probes and angle-
beam probes both in contact technique. It is to be used for UT examination on ferritic and austenitic
welds and base material as search techniques and for comparison with acceptance criteria by the
national referencing nuclear safety standards. Immersion technique and techniques for sizing are not
in the scope of this document and are independent qualified.
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.
Unless otherwise specified in national nuclear safety standards the minimum requirements of this document are
applicable. This document does not define:
— extent of examination and scanning plans;
— acceptance criteria;
— UT techniques for dissimilar metal welds and for sizing (have to be qualified separately);
— immersion techniques;
— time-of-flight diffraction technique (TOFD).
It is recommended that UT examinations are nearly related to the component, the type and size of defects to be
considered and are reviewed in specific national inspection qualifications.
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 5577, Non-destructive testing — Ultrasonic testing — Vocabulary
ISO 8596, Ophthalmic optics — Visual acuity testing — Standard and clinical optotypes and their
presentation
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting
ISO 18490, Non-destructive testing — Evaluation of vision acuity of NDT personnel
EN 12668-1, Non-destructive testing — Characterization and verification of ultrasonic examination
equipment — Part 1: Instruments
EN 12668-2, Non-destructive testing — Characterization and verification of ultrasonic examination
equipment — Part 2: Probes
ISO 18563-1, Non-destructive testing — Characterization and verification of ultrasonic phased array
equipment — Part 1: Instruments
ISO 18563-2, Non-destructive testing — Characterization and verification of ultrasonic phased array
equipment — Part 2: Probes
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5577 and the following 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
analysis scan
test scan with adopted parameters that is required for more precise characterisation of an indication (3.3)
3.2
analysis technique
test technique that is applied for more precise characterisation of indications (3.3) subject to analysis
3.3
indication
representation or signal from a discontinuity in the format allowed by the NDT method used
[SOURCE: ISO/TS 18173:2005, 2.14]
Note 1 to entry: Signal that is initiated by operationally induced damage mechanisms, geometrical as well as,
material or design induced influences
3.4
evaluation
assessment (3.5) of indications (3.3) revealed by NDT against a predefined level
Note 1 to entry: Inspection of the recorded measured data in respect to completeness and analysis capacity,
localisation and registration of indications according to defined criteria, representation of the test results
[SOURCE: EN 1330-2:1998, 2.10]
3.5
assessment
comparison of the analysed measuring results with specified criteria
2 © ISO 2020 – All rights reserved

3.6
data storage medium
storage medium for storing digital media
3.7
focal length
focal distance
distance from the probe to the focal point
[SOURCE: ISO 5577:2017, 4.2.13]
3.8
focus range
focal zone
zone in sound beam of a probe in which the sound pressure remains above a defined level related to
its maximum
[SOURCE: ISO 5577:2017, 4.2.14]
Note 1 to entry: During measurement with the electrodynamic probe in sound transmission, this value
corresponds to a decrease in the signal level by 3 dB in comparison to the maximum value.
Note 2 to entry: In general limitation by the decline in the signal level by 6 dB.
3.9
focus depth
focal point
point where the sound pressure on the beam axis is at its maximum
[SOURCE: ISO 5577:2017, 4.2.12]
3.10
adjustment
setting the ultrasonic test device based on specified parameters
3.11
calibration
determination of the measuring value range of an ultrasonic test device in relation
to a calibrated test standard
3.12
calibration block
piece of material of specified composition, surface finish, heat treatment and
geometric form, by means of which ultrasonic test equipment (3.43) can be assessed and calibrated
[SOURCE: ISO 5577:2017, 5.4.1]
Note 1 to entry: The calibration blocks according to ISO 2400 and ISO 7963 can be used as calibration blocks
according to this document.
3.13
calibration reflector
reflector of a known geometry and size in or on the calibration block (3.12), test reference block (3.15) on
the test calibration block, for distance or sensitivity adjustment of the ultrasonic test instrument (3.44)
3.14
component
part of a system delimited according to structural or functional aspects, which can still implement
independent sub-functions
3.15
reference block
block of material representative of the material to be tested with similar acoustic properties containing
well-defined reflectors, used to adjust the sensitivity and/or time base of the ultrasonic instrument
(3.44) in order to compare detected discontinuity indications (3.3) with those arising from the known
reflectors
[SOURCE: ISO 5577:2017, 5.4.2]
3.16
time of flight
time it takes an ultrasonic pulse to travel from the transmitter probe through the test object (3.27) to
the receiver probe
[SOURCE: ISO 5577:2017, 3.2.6]
Note 1 to entry: This comprises the lead time in the UT probe and the time of flight in the component; it is the
time that an ultrasonic pulse requires from the oscillator to a reflector and back to the oscillator.
3.17
LLL technique
test technique based on the reflection of the sound package at the back wall and at a planar reflector in
the inspection volume using /utilizing longitudinal waves
Note 1 to entry: See Annex A, no. 7.
3.18
LLT technique
test technique based on reflection of the sound bundle at the back wall and at a planar reflector in the
inspection volume using/utilizing the mode conversion of longitudinal waves and transversal waves
Note 1 to entry: See Annex A, no. 7.
3.19
measurement scan
movement of the UT probes with simultaneous recording of measured data
3.20
raw data
all measured data and setting parameters saved by the ultrasonic test equipment during the
measurement run (recorded and saved data)
Note 1 to entry: Examples of raw data include amplitude, time of flight, and coordinates.
3.21
test section
part of the test area (3.23)
3.22
test supervisor
responsible for application of the test method and for the individual details of the test implementation
including monitoring of the activities for preparation and implementation of the test as well as analysis
of the test results (3.24)
3.23
test area
defined area on the test object (3.27) over which the tests are to be conducted
[SOURCE: ISO 5577:2017, 6.2.2]
4 © ISO 2020 – All rights reserved

3.24
test result
summarising evaluation of all measured data and comparison with the previous test
3.25
test scan
measuring run with the characteristics specified in the test specifications
3.26
test function
test task assigned to a UT probe or UT probe combination, e.g. coupling check
3.27
test object
object to be tested; object under test or examination; part of a component to be tested
3.28
test robots
scanner
mechanical device with control for guiding the UT probes
3.29
noise level
amplitudes of background noise in an ultrasonic system
Note 1 to entry: 95 % value of the sum frequency of the amplitudes, measured during the reference run or test
run in an indication-free range
[SOURCE: ISO 5577:2017, 6.5.16]
3.30
signal to noise ratio
ratio of the amplitude of a signal arising from a discontinuity in a material to the amplitude of the
average background noise level (3.29)
[SOURCE: EN 1330-2:1998, 2.16]
3.31
reference scan
measuring run for the functional control and functional adaptation of the ultrasonic test equipment
3.32
hysteresis correction
correction to the decrease in the calibration level resulting during the tandem test or during the test
with a comparable test system, if the planar reflectors are not oriented vertically to the surface or
vertically to the sound incidence level
3.33
transmitter-receiver technique (TR-technique)
pitch and catch technique
double probe technique
ultrasonic testing technique involving the use of two probes both of which can be used as transmitter
and receiver
3.34
track offset correction
correction to the decrease in the calibration level of planar reflectors in the middle between two tracks
3.35
tandem zone correction
correction to the decrease in the calibration level of the calibration reflector to the tandem zone edges
3.36
test block
defined piece of material which allows tests for the accuracy and/or performance of an ultrasonic test
system (3.43)
[SOURCE: ISO 5577:2017, 5.4.3]
Note 1 to entry: Specimen for examining properties of a test method, an ultrasonic test instrument or a test system.
3.37
depth zone
sub-range of the wall thicknesses to be tested
3.38
transfer correction
correction of the gain setting of the ultrasonic test instrument (3.44) when transferring the probe from a
calibration (3.12) or reference block (3.15) to the test object
[SOURCE: ISO 5577:2017, 5.4.5]
3.39
trigger distance
path that the UT probes travels between two test cycles of the same test function following in succession
3.40
scan without couplant
measurement scan (3.19) without coupling between the UT probe and test object (3.27)
3.41
TTT technique
test technique based on reflection of the sound bundle at the back wall and at a planar reflector in the
test volume using / utilizing shear waves
Note 1 to entry: See Annex A, no. 7.
3.42
ultrasonic test equipment
equipment consisting of an ultrasonic instrument (3.44), probes, cables and all devices connected to the
instrument during testing
[SOURCE: ISO 5577:2017, 5.3.1]
Note 1 to entry: Connected devices consist also test robot and analysis unit including software, digitalisation
unit and, if necessary, operating PC including software.
3.43
ultrasonic test instrument
instrument used together with the probe or probes, which transmits, receives, processes and displays
ultrasonic signals for NDT purposes
[SOURCE: ISO 5577:2017, 5.1.1]
3.44
ultrasonic test technique
application-relevant technique for the localisation of discontinuities (internal or surface open)
Note 1 to entry: In relation to the application, requirements result for these ultrasonic test techniques in respect
to the test parameters such as oscillation variable, beam angle, wave type and frequency.
Note 2 to entry: Test techniques are e.g. pulse-echo system (PE), transmitter-receiver system (TR), tandem
system, phased-array system (PA).
6 © ISO 2020 – All rights reserved

3.45
reference reflector
reflector (natural or artificial) with known form, size and distance from the test surface in the
calibration block (3.12) or reference block (3.15), which is used for calibration or assessment of detection
sensitivity
Note 1 to entry: A reference reflector can also be used as a calibration reflector.
3.46
angle-dependent amplification compensation
correction to the echo level for compensation of the sound pressure change in relation to the beam
angle at phased-array probes
Note 1 to entry: See Figures D.2 and D.3.
[SOURCE: ISO 5577:2017, 6.4.2]
4 Test systems
4.1 Preliminary remark
The suitability of the test technique and the test device system shall be validated corresponding to the
requirements of the applicable national nuclear safety standards.
[6]
NOTE The procedure for the qualification is described in ENIQ report no. 31 .
A general test procedure shall be prepared. Annex E contains the items of the general test procedure.
4.2 General
The test techniques described below are used to locate discontinuities (search techniques). Test
techniques for the analysis of indications can be found in 6.4.
The relevant test sections shall be checked so that the required registration thresholds are complied
with in even the least favourable case. This results in requirements e.g. for the track offset correction,
the transfer correction, the trigger distance and the travel speed, that depend on the relevant selection
of probes (e.g. oscillation variable, test frequency, beam angle) and the depth range to be tested.
Depending on the test assignment, the following probes shall be used in contact technique:
— Single transducer probes;
— TR-probes;
— Phased-array probes;
— Electromagnetic acoustic transducer (EMAT).
NOTE The specific requirements for the use of EMAT probes are not discussed in this document.
In the case of tests on austenitic components and dissimilar metal welds, the test capacity can be
impaired by the weld metal structure (e.g. inherent coarse-grained and/or a directionally-oriented
structure). This can cause variations in attenuation, reflection, refraction at grain boundaries and
velocity changes within the grains. It usually is necessary to modify and/or supplement the general
settings of this standard when examining such welds or base materials. Additional items could be weld
mock-ups with reference reflectors in the weld deposit and weld area and single or dual longitudinal
angle beam probes.
4.3 Validation and localisation of reflectors
4.3.1 Pulse-echo technique (PE technique)
The PE technique (see Annex A, No. 1 and No. 2) records the total wall thickness range. It is used with
longitudinal and transversal/shear waves and with various beam angles and test frequencies.
A reflector is localised via the measurement of the sound path at known UT probe position, known beam
direction and known beam angle. For setting the test sensitivity for the area of interest see 6.1.6.3.
4.3.2 Transmitter-Receiver technique (TR-technique)
The TR-technique (see Annex A, No. 3 and No. 4) records the wall thickness range in which the sound
fields of transmission and reception converters overlap. The TR-technique is used with longitudinal
waves (TRL) or transversal waves (TRT) with various beam angles and test frequencies.
A reflector is localised via the measurement of the sound path at known UT probe position, known
beam direction and known beam angle.
4.3.3 Tandem technique
The tandem technique (see Annex A, No. 5) is used when testing in test areas with plane-parallel or
concentric surfaces. This technique primarily serves for the detection of planar reflectors oriented
normally to the surface. This utilises two UT probes that transmit and receive transversal waves each
with nominal beam angle of 45°. To prevent mode conversions beam angle and reflection angle should
be in the range from 40° to 50° when applying transversal wave UT probes for the tandem technique.
It is recommended that also probes with longitudinal waves can be used, but mode conversion can be
occurred.
The localisation of a reflector in respect to the depth location is possible by indication of the depth zone.
It depends on
— the wall thickness,
— the distance of the two UT probes, and
— the angles of incidence of the transmitter probe and the receiver probe.
In the case of the tandem technique, the depth zones shall cover the reflector expectation range with
consideration of surface irregularities and, if necessary, wall thickness changes.
In case of curved surfaces, the change in the sound path due to the geometry shall be considered.
4.3.4 Inspection technique with mode conversion
An ultrasonic inspection technique that uses the conversion of longitudinal waves in transversal/shear
waves or vice versa (LLT technique), is used for the validation of surface connected and embedded
indications (see Annex A, No. 7). It is also possible to use a technique which reflect the UT sound by
utilizing only longitudinal waves (LLL technique) or only transversal waves (TTT technique).
The reflector location is determined by measuring the time of flight at known UT probe position, known
sound direction and known beam angle in relation to the wave mode. The actual sound path cannot be
read off directly owing to the conversion into wave modes with different sound velocities. An ultrasonic
test technique with mode conversion shall be verified with measurements at a reference block.
In the mode conversion technique, the depth zones shall cover the indication expectation range with
consideration of flaw inclined positions, surface irregularities and, if applicable, wall thickness changes.
NOTE In practice, test techniques are used, which are characterised by two spatially separated transducers
with the same beam direction and usually with different angles of incidence, whereby one transducer serves for
transmission and the other for reception.
8 © ISO 2020 – All rights reserved

4.3.5 V-transmission technique
The V-transmission technique (see Annex A, No. 8) is used for recording the coupling and transfer
fluctuations and for the validation of large material separations (in relation to the sound beam) when
testing components.
4.3.6 Phased-Array technique (PA)
The PA-technique (see Annex A, No. 6) can be used as a fixed angle probe α (E-scan) or as a group
radiation system with a swivel angle range α to α (S-scan) using linear array as preferred search units.
0 n
Other than linear array probes can be used. The usage and the comparability to PE- or linear PA-
technique shall be shown on the basis of a qualification.
4.3.7 Preferred angles of incidence and wave modes for search techniques
Taking the optimum incidence angle into consideration, the beam angles and wave modes shall
preferably be selected according to Table 1 for the search techniques.
Table 1 — Preferred beam angle and wave modes
a d d
Location of the reflector Beam angle PE system TR system EMAT
close to probe 0° — L —
c
45° T T —
b
≥ 65° — L TH
Close to
surface
far from probe 0° L — —
e b
30° to 70° T T (L ) TH
In the volume 0° L L —
e b
40° to 70° T T (L ) TH
Inspection techniques to be used are marked by L, T or TH (see Annex A). Those not to be used are marked by a dash
(—).
a
Depending on the geometry of the test object, other beam angles may also be used.
b
Electromagnetically excited horizontally polarised transversal waves (TH). The equivalence shall be validated by a
qualification.
c
When testing over the full path.
d
Both techniques can also be implemented by using PA probes.
e
For austenitic welds or base material the longitudinal waves are less effected by coarse grain structure of austenitic
material.
For the testing of materials that are difficult to test, for inspection techniques with mode conversion as
well as in the case of complicated geometries, the beam angle and the test frequency shall be adapted to
the test assignment and their suitability validated by measurements on reference block.
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 should 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 2).
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 operating personnel for test robots, operating personnel for ultrasonic
test devices and analysts as well as the test supervisor.
Those personnel, using qualified NDT procedures and equipment, shall be qualified through one or any
combination of the following:
a) certification through a national NDT personnel certification scheme;
b) theoretical and/or open trials;
c) blind trials.
Any personnel certification requirements invoking relevant national NDT personnel certification
schemes (e.g. see ISO 9712) shall be validated according to Table 2. Any additional personnel training
requirements shall also be specified in the qualification dossier.
If no relevant scheme exists or if extra personnel qualification is needed, the qualification body shall
determine the additional practical and theoretical examinations needed beyond those in the national
certification scheme, include these in the qualification procedure and ensure that the NDT procedure also
includes the necessary requirements. The qualification procedure shall describe the proposed system.
The test supervisor is responsible for the application of the NDT qualified system and shall have
the knowledge required for his tasks as well as sufficient knowledge of the application options and
limitations of the test methods and have knowledge about the characteristic appearances of operation-
induced flaws. Indications that reach or exceed the acceptance level shall be evaluated by the test
supervisor, who has the requisite experience in respect to the test object, test assignment, test method
and device system.
The operating personnel for test robots and ultrasonic test devices shall be trained for the special
requirements of the work to be performed. In particular, they shall have adequate experience in the
implementation of automated ultrasonic tests and knowledge about the test object in respect to these
requirements.
The analysts shall be trained for the special requirements of the work to be performed and have
experience in the analysis and evaluation of UT indications as well as knowledge of the test object and
the characteristic appearance of indications.
10 © ISO 2020 – All rights reserved

Test personnel performing NDT and the evaluation of the results shall be qualified in accordance with
ISO 9712 or equivalent at an appropriate level in the relevant industrial sector.
Table 2 — Minimum requirements for the test personnel
Test personnel Qualification
Operating personnel for test robots Validation by training
Operating personnel for ultrasonic test Certified with at least level 2 according to ISO 9712 or comparable
devices (test inspector) qualification
Analysts Certified with at least level 2 according to ISO 9712 or comparable
qualification
Test supervisor Certified with level 3 according to ISO 9712
The test personnel shall fulfil the vision requirements of ISO 9712.
The test personnel shall provide annual validation of their visual ability, which has been determined
by an ophthalmologist, optician or other medically recognised person. The vision requirements of
ISO 9712 shall be fulfilled. The following modifications can be used as substitutes to ISO 9712.
d) The visual acuity testing shall be conducted with standard signs in accordance with ISO 8596
(Landolt rings) or ISO 18490 (E shaped character). Here a near vision acuity of 1,0 at a test distance
of 0,33 m with at least one eye, with or without optical aid shall be validated.
e) The ability to distinguish between colours and between grey shadowing shall be validated with
colour sense test boards. The validation can typically be conducted with the help of Ishihara colour
boards as well as the "shades of grey test". In case of anomalies, the employer shall decide whether
the ability to see colours is sufficient for the test assignment.
5.2 Test object
The weld crown condition shall be ground flush or machined to allow for unobstructed access to the
weld (scan over weld deposit). The examination surfaces shall be free of irregularities, loose material,
or coatings, which interfere with the ultrasonic wave transmission. Areas where ultrasonic contact is
inadequate shall be documented as limitations.
Reference points shall be permanently marked on the component for positioning and calibration.
5.3 Ultrasonic test equipment
5.3.1 Preliminary remark
The ultrasonic test equipment shall fulfil the requirements for electromagnetic compatibility.
5.3.2 Test robot
The test robot (also called remote handling manipulator) shall fulfil the requirements for occupational
safety and enable a time-saving, non-mix-up assembly and operation, to limit the radiation exposure of
the test personnel.
The test robot shall be designed so that:
— the test section specified in the test procedures is recorded;
— a reproducible local tolerance of 3 mm is not exceeded within a measurement for the mechanical
components;
— an assembly global tolerance of 5 mm to the component coordinate system on the component is not
exceeded;
— the track pitch upon meander measurement does not deviate from the target value by more than 20 %;
NOTE Test system requirements can make higher accuracies necessary.
— an encounter with obstacles is prevented (e.g. by limit switch);
— all components are secured against automatic or unintended loosening, falling or tipping;
— the UT probe or UT probe system is moved with the required contact pressure over the entire
test area;
— the position data with a resolution of less than or equal to 1 mm is continuously available;
— the position data can be converted in component-related coordinates;
— the electrical interference level resulting from drive and control elements is below the level of the
joint indications in the relevant test section;
— the cable connections are designed to prevent mix-ups (e.g. by marking);
— the robot can be extensively decontaminated.
5.3.3 Ultrasonic test device
The characteristics of the ultrasonic test device shall be verified in accordance with EN 12668-1 for
analogue and digital ultrasonic instruments for pulse operation and in automated systems and with
ISO 18563-1 for phased-array ultrasonic instruments.
The following device system properties shall be documented by the manufacturer:
— number of transmitter and receiver channels;
— raw data type (e.g.: RF., A-Scan);
— amplitude and time progression of the transmitted signal;
— maximum transmitting pulse repetition frequency;
— scanning rate;
— frequency filter;
— output impedance of the transmitter;
— input impedance of the receiver;
— cross-talk between transmitter and receiver channels;
— amplifier type (linear, logarithmic);
— dynamic range;
— resolution for the signal amplitude;
— frequency bandwidth of the receiver;
— software version;
— data reduction algorithm;
— protection standard (e.g. splash waterproof, immersion-proof).
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The ultrasonic test device shall fulfil the following requirements.
— The relative measuring uncertainty of the time of flight shall not exceed 1 %. The manufacturer shall
ensure that this requirement is fulfilled in the entire frequency range of the ultrasonic test device.
— Mix-up of the storage of raw data shall be prevented.
— The option of monitoring measuring value for each test channel during the data collection/
acquisition shall be provided.
— If a depth or angle
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