ISO 20890-4-2020 PDF

Full title and description

Guidelines for in-service inspections for primary coolant circuit components of light water reactors — Part 4: Visual testing. This International Standard provides guidance for pre-service inspection (PSI) and in-service inspection (ISI) of reactor coolant circuit components using direct and remote (mechanized) visual testing methods, with emphasis on remote visual inspection techniques and general requirements for direct visual inspection.

Abstract

This document gives guidelines for PSI and ISI of primary coolant circuit components of light water reactors and related installations as either general (overview) or selective visual testing. It covers remote (mechanized) visual testing as the primary focus, specifies requirements for equipment and personnel, describes preparation and performance of inspections, and defines recording and reporting expectations. It is also applicable to other nuclear installation components and does not replace national requirements for inspection intervals, test extent or evaluation criteria.

General information

• Status: Published (confirmed in 2025; remains current).
• Publication date: 12 June 2020.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 27.120.10 (Reactor engineering / nuclear reactor technology).
• Edition / version: Edition 1 (2020).
• Number of pages: 14.

Key bibliographic and status details above are drawn from the ISO bibliographic entry for ISO 20890-4:2020.

Scope

The standard provides guidelines for performing visual inspections (direct and remote) on components of the reactor primary coolant circuit in light water reactors. It addresses inspection types (general overview and selective inspection), technology and equipment requirements for remote visual systems, qualification and competence expectations for inspection personnel, preparation and performance practices, and recording/ reporting of findings. It explicitly excludes routine pressure/leak testing and general plant inspections; details on inspection intervals, test sections and acceptance/evaluation criteria are left to applicable national nuclear safety standards.

Key topics and requirements

• Distinction between general (overview) visual testing and selective visual testing (targeted, property-specific inspection).
• Emphasis on remote (mechanized) visual inspection systems: equipment, lighting, optics, and image recording.
• General requirements for direct visual testing and cross-reference to weld-specific direct visual standards (e.g., ISO 17637).
• Specification of personnel qualifications, inspection preparation, inspection execution and documentation/record-keeping.
• Guidance that national nuclear safety standards determine inspection intervals, acceptance criteria and test extents.

Typical use and users

Used by nuclear utilities, reactor maintenance and inspection teams, NDE (non-destructive examination) service providers, plant safety engineers, and regulators involved in in-service inspection programs for light water reactors. It serves as a practical guidance document for inspection planning, procurement of remote visual inspection equipment, qualification of inspection personnel, and preparation of inspection records and reports.

Related standards

ISO 20890-4 is part of the ISO 20890 series for in-service inspection guidance for primary coolant circuit components (other parts include mechanized ultrasonic testing, magnetic particle and penetrant testing, and hydrostatic testing). It cross-references ISO 17637 for direct visual inspection of welds and cites relevant EN standards on visual testing and equipment where appropriate. Representative related documents include ISO 20890-1:2020, ISO 20890-2:2020, ISO 20890-3:2020, and ISO 17637.

Keywords

in-service inspection; PSI; ISI; visual testing; remote visual inspection; mechanized inspection; reactor coolant circuit; light water reactor; NDE; non-destructive examination; inspection equipment; inspection personnel; recording and reporting.

FAQ

Q: What is this standard?

A: ISO 20890-4:2020 is an ISO International Standard that provides guidelines for pre-service and in-service visual inspections of primary coolant circuit components in light water reactors, with a focus on remote (mechanized) visual testing.

Q: What does it cover?

A: It covers general and selective visual testing methods, requirements for inspection equipment and personnel, preparation and performance of inspections, and recording/reporting practices. It does not set national inspection intervals or acceptance criteria (those remain the responsibility of national nuclear safety standards).

Q: Who typically uses it?

A: Nuclear plant operators, NDE contractors, inspection engineers, maintenance teams and regulatory bodies involved in reactor component inspections and fitness-for-service assessments.

Q: Is it current or superseded?

A: The 2020 edition (Edition 1) was published on 12 June 2020 and, according to ISO records, was reviewed and confirmed in 2025, so the 2020 text remains the current version. Users should check national or ISO catalogues for any later amendments or revisions.

Q: Is it part of a series?

A: Yes. ISO 20890-4 is Part 4 of the ISO 20890 series covering guidelines for in-service inspections of primary coolant circuit components; other parts include mechanized ultrasonic testing (Part 1), magnetic particle and penetrant testing (Part 2), and hydrostatic testing (Part 3).

Q: What are the key keywords?

A: Visual testing; remote visual inspection; in-service inspection (ISI); pre-service inspection (PSI); reactor coolant circuit; light water reactor; NDE; inspection equipment; inspection personnel; recording and reporting.