BS ISO 20890-4:2020 pdf download.Guidelines for in-service inspections for primary coolant circuit components of light water reactors — Part 4: Visual testing.
This document gives guidelines for pre-service inspection (PSl) and in-service inspections (ISIl) forreactor coolant circuit components of light water reactors and their installations as direct or remotevisual 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 thisdocument focuses on remote (mechanized) visual testing, but also specifies global requirements fordirect 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 conjunctionwith 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 thetesting as well as the recording.
NOTE Data concerning the test section, test extent, inspection period, inspection interval and evaluation ofindications is defined in the applicable national nuclear safety standards.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.ISO 8596,Ophthalmic optics — Visual acuity testing —Standard and clinical optotypes and theirpresentation
ISO 9712:2012,Non-destructive testing —Qualification and certification of NDT personnelISO 18490, Non-destructive testing — Evaluation of vision acuity of NDT personnel
EN1330-10,Non-destructive testing —Terminology— Part 10: Terms used in visual testingEN 13018,Non-destructive testing -Visual testing —General principles
EN 13927,Non-destructive testing — Visual testing —Equipment
3Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1330-10 and the following apply.
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) orsurfaces to be examined in respect to cracks, wear, corrosion, erosion or mechanical damage on the surface oftheparts or components ( 3.10].
3.10 component
part of a system delimited according to structural or functional aspects, which can still implementindependent sub-functions
3.11 reference standard
<visualtesting> specimen for inspectingthe settings of thetestsystem and itsfunction duringthe testingNote 1 to entry: Test images (e.g.colour boards according to Annex A or similar test images) are used as referencestandards during the visual testing. Depending on the test assignment and device system, a scalability of testimages can be necessary.
3.12 mechanized visual testing
remote visual testing (3.8) with mechanized guidance of camera or video-endoscope3.13
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 performanceincluding monitoring of the activities for preparation and performance of the test as well as analysis ofthe 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
4 Inspection technique
Visual testing is used to recognise deviations from the expected state.This state is specified in the testprocedures. Depending on the test assignment, the visual testing is conducted either as a general visualtesting 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 visualtesting.The local radiation dose rate shall be considered when selecting the inspection techniques andauxiliaries.
The suitability of the inspection technique and the combined device system shall be validated accordingto the requirements of the applicable nuclear safety standards.
NOTE1 The procedure for the qualification of the inspection techniques or the combined device system isdescribed in ENiQ report nr. 31[3].
NOTE2 The visual testing test method discussed in this document involves a standardized test method whoseapplication is realised based on standard test procedures relating to nuclear power plants. A qualification asabove can be necessary in individual cases if there are significant deviations from the specifications from thetest procedures.
A general test procedure shall be prepared.Annex B contains the items of the general test procedure.
5 Requirements
5.1Test personnel
5.1.1 Task of NDT personnel
NDT personnel4 have a great responsibility, not only with respect to their employers or contractorsbut aiso under the rules of good workmanship.The NDT personnel shall be independent and free fromeconomic influences with regard to his test results, otherwise the results may be compromised. TheNDT personnel shall be aware of the importance of his signature and the consequences of incorrecttest results for safety, health and environment.Under legal aspects, the falsification of certificates is anoffence and judged according to the national legal regulations. A tester may find himself in a conflictingsituation 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 isalso always intended.
5.1.2Personnel requirements
The test personnel comprise the test inspector, the test supervisor and possibly the operating personnelfor the test robot.BS ISO 20890-4 pdf download.

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