Description of BS ISO 20890-1:2020 2020
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.
About BSI
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