PNAE G-7-032-91 PDF

Full title and description

PNAE G-7-032-91 — Uniform control methods for basic materials (semi-finished materials), welded joints and weldings of equipment and pipelines of nuclear power plants. Ultrasonic testing. Part IV. Examination of welded joints of austenitic steels. The document defines procedures, calibration samples, scanning techniques and acceptance criteria for ultrasonic inspection of austenitic-class steel welds used in nuclear power plant equipment and piping.

Abstract

This technical regulatory document specifies ultrasonic testing (UT) methods for butt-welded joints fabricated from austenitic steels used in nuclear power installations. It covers requirements for test samples, transducer types and orientations (inclined, direct, head-wave), sensitivity calibration, scanning patterns (longitudinal, transverse, combined motions and limited rotation), controlability checks against structural noise, defect-characteristics measurement and reporting. Typical thickness range addressed is approximately 10–60 mm and procedures include limits on scanning speed and operator qualification requirements.

General information

• Status: Withdrawn / not effective; superseded in practice and removed from obligatory application by later regulatory action (see notes below).
• Publication date: Approved October 31, 1991.
• Publisher: USSR State Inspection (approving authority for the original text).
• ICS / categories: Nuclear energy / Non-destructive testing (ultrasonic testing); ISO/ICS classification related to 27.120 (nuclear energy) and NDT methods.
• Edition / version: Original 1991 edition (Part IV of the PNAE G-7-032 series).
• Number of pages: 11 (document electronic version typically listed as 11 pages in public catalogues).

Document metadata and status references are recorded in national normative catalogs and commercial document libraries.

Scope

The standard applies to butt-welded joints of equipment, vessels and pipelines of nuclear energy installations made and inspected in accordance with the accompanying PNAE design and testing rules. It is aimed specifically at welded joints from austenitic-class steels with wall thicknesses typically in the 10–60 mm range and with specified curvature radii for longitudinal and circumferential welds; it excludes certain cast austenitic welds and limits controlability where structural noise prevents reliable defect detection. Use for particular products is determined by the responsible materials/industry authority.

Key topics and requirements

• Calibration and control samples: use of representative reference blocks (analogous to СО №3 per GOST 14782-86) and specially made specimens for sensitivity setting and controlability checks.
• Transducer types and modes: inclined (angle) transducers for longitudinal and shear waves, direct RS-type transducers, and head-wave techniques where applicable.
• Scanning procedures: longitudinal and transverse scans, combined motions with ±15° rotation where required, and recommended overlap and scanning step limits.
• Sensitivity and controlability: procedures to set search and fixation levels using notches/holes on reference samples and criteria to declare a weld non-controleable if signal-to-noise thresholds are not met (e.g., 6 dB margin rule for notch echo vs structural noise).
• Operator qualifications: requirement for experienced, certified defectoscopists (document cites high-grade qualification and periodic re-testing—practical nuclear-industry practice includes annual proficiency checks oriented to austenitic material controlability).
• Defect measurement and reporting: coordinates, echo amplitude and conditional length to be recorded; limits on scanning speed (example: ≤ 50 mm/s) and scan step sizes tied to piezoelement dimensions.

Typical use and users

The standard is used by NDT/ultrasonic inspection teams, QA/QC engineers, welding engineers, plant maintenance and fitness-for-service groups at nuclear power plants, fabricators of nuclear-grade equipment and regulatory inspectors responsible for oversight of in-service and acceptance testing of pressure equipment and piping. It serves as a methodical reference for laboratories performing UT of austenitic welds where structural noise and metallurgical features complicate defect detection.

Related standards

PNAE G-7-032-91 is part of a set of PNAE documents for equipment and piping of nuclear energy installations and references other PNAE items such as PNAE G-7-008-89 (design and safe operation rules), PNAE G-7-009-89 (welding and overlaying general provisions) and PNAE G-7-010-89 (testing rules for welded joints). In later practice the subject matter has been incorporated into and superseded by newer national/regulatory NDT standards (e.g., referenced replacement standards published in the 2010s).

Keywords

ultrasonic testing, austenitic steels, welded joints, nuclear power plants, non-destructive testing, control samples, calibration, defectoscopy, weld inspection, PNAE

FAQ

Q: What is this standard?

A: It is Part IV of a PNAE-method series giving unified ultrasonic testing methods for materials and welds used in nuclear power plant equipment, with a focus on austenitic-steel welded joints.

Q: What does it cover?

A: Procedures for preparing calibration samples, setting UT sensitivity, scanning techniques (angles, directions, motions), controlability checks for structural noise, criteria for defect detection and measurement, operator qualification and reporting requirements for austenitic weld inspection.

Q: Who typically uses it?

A: NDT technicians and defectoscopists, welding and inspection engineers at nuclear power plants and fabricators, and regulatory/oversight inspectors involved in acceptance and in-service testing of critical equipment and piping.

Q: Is it current or superseded?

A: The original 1991 text has been withdrawn from mandatory use in later regulatory updates and practical application has moved to newer national standards and regulatory documents (catalogues list it as replaced or not effective; later documents covering similar topics include GOST R–type NDT standards published in the 2010s).

Q: Is it part of a series?

A: Yes — it is Part IV of the PNAE G-7-032 series on unified control methods for materials and welds (Ultrasonic testing) and should be used together with related PNAE documents governing welding, testing rules and equipment specific provisions.

Q: What are the key keywords?

A: Ultrasonic testing; austenitic steels; welded joints; nuclear power; NDT; calibration samples; controlability; defect measurement.