BS ISO 20890-1:2020

This standard BS ISO 20890-1:2020 Guidelines for in-service inspections for primary coolant circuit components of light water reactors is classified in these ICS categories:

• 27.120.10 Reactor engineering

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

1. fault indications (e.g. on austenitic weld seams or complex geometry),

2. indications due to geometry (e.g. in case of root concavity),

3. complex geometries (e.g. fitting weld seams), or

4. 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.