BS ISO 20890-4:2020 pdf free.Guidelines for in-service inspections for primary coolant circuit components of light water reactors  Visual testing.
BS ISO 20890-4 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.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.NOTE1 The procedure for the qualification of the inspection techniques or the combined device system is described in ENIQ report nr. 31[3]. NOTE2 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.BS ISO 20890-4 pdf download.