PNAE G-7-031-91 PDF
Name in English:
PNAE G-7-031-91
Name in Russian:
ПНАЭ Г-7-031-91
Uniform control methods for basic materials (semi-finished materials), welded joints and weldings on of equipment and pipelines of nuclear power plants. Ultrasonic testing. Part III. Thickness measurement of monometals, metals and corrosion resistant coatings
Full title and description
ПНАЭ Г-7-031-91 — «Унифицированные методики контроля основных материалов (полуфабрикатов), сварных соединений и наплавки оборудования и трубопроводов атомных энергетических установок. Ультразвуковой контроль. Часть III. Измерение толщины монометаллов, биметаллов и антикоррозионных покрытий». Документ устанавливает процедуру измерения толщины монo‑ и биметаллических изделий и толщины антикоррозионных покрытий методом ультразвукового эхо‑импульсного контроля для оборудования и трубопроводов атомных энергетических установок.
Abstract
Standard PNAE G-7-031-91 specifies requirements for ultrasonic echo‑pulse thickness measurement of monometallic and bimetallic components and of anti-corrosion (cladding/surfacing) coatings used on equipment and piping of nuclear power plants. It covers calibration blocks and setup, measurement procedures, error estimation, personnel attestation, environmental and preparation requirements, and documentation of results.
General information
- Status: Withdrawn / not applicable (cancelled by order of Rostekhnadzor No. 360 dated 13 August 2018).
- Publication date: Approved 31 October 1991; introduced (date of effect) 1 October 1992; cancellation date 13 August 2018.
- Publisher: ГОСПРОМАТОМНАДЗОР СССР (USSR State Inspection for Atomic Energy / state atomic supervision body).
- ICS / categories: Nuclear power engineering; non‑destructive testing; ultrasonic inspection (ICS class about 27.120 — nuclear power engineering / NDT).
- Edition / version: Original issue (1991 / implemented 1992).
- Number of pages: 25 pages.
Scope
The standard applies to ultrasonic thickness measurement of base metals (mono‑ and bimetallic parts) and of anti‑corrosion coatings (claddings and surfacings) on equipment and piping covered by the PNAE G‑7 series of rules for nuclear installations. It is intended for use where PNAE G-7-010-89 (inspection rules) and PNAE G-7-008-89 (design and safe operation rules) apply. The scope covers required instrumentation, calibration specimens, measurement locations and sampling, environmental and surface preparation, limitations of the ultrasonic method, criteria for accepting measurement results, and required records.
Key topics and requirements
- Ultrasonic echo‑pulse method for thickness measurement of monometals, bimetals and anti‑corrosion coatings.
- Required instruments: ultrasonic thickness gauges with digital readout; defectoscopes of group 2 and above per GOST 23049‑89; specific probe types and calibration block types (T1, T2, TB1, TN1, TN2) for various measurements.
- Calibration and instrument setup procedures, including recommended standard blocks and calibration sequences.
- Measurement procedure: preparation of measurement points, recommended number of independent readings on prepared areas, rules for discarding gross errors and averaging.
- Error analysis and reporting: systematic and random error estimation, statistical treatment of measurements, and determination of measurement uncertainty and confidence intervals.
- Qualification and attestation of controllers/inspectors consistent with PNAE G-7-010-89 requirements.
- Limitations of the method: effects of small localized pitting, curvature, coating heterogeneity and near‑surface anomalies on measurement accuracy and interpretability.
- Documentation and traceability: measurement maps, records of settings, environmental conditions, calibration records and result protocols.
- Safety and working conditions for conducting ultrasonic thickness measurements on nuclear plant equipment and piping.
Typical use and users
Primary users are nondestructive testing (NDT) engineers and technicians, quality control departments, plant maintenance/condition‑monitoring teams, manufacturers and fabricators of nuclear equipment, and regulatory/supervisory bodies responsible for nuclear plant safety and inspection. Use cases include in‑service thickness monitoring, pre‑service inspection, verification of cladding and surfacing layers, and acceptance testing during manufacture or repair.
Related standards
Closely related documents include PNAE G-7-010-89 (rules for welded joints and surfacings inspection), PNAE G-7-014-89 (Part I — control of base materials), PNAE G-7-030-91 (Part II — ultrasonic inspection of welded joints and surfacings), GOST 23049-89 (ultrasonic defectoscopes classification), and GOST 2789-73 (surface roughness parameters) among other national NDT and nuclear equipment regulations.
Keywords
ultrasonic thickness measurement; ultrasonic testing; PNAE G-7-031-91; monometal; bimetal; cladding; anti‑corrosion coating; nuclear power plant; nondestructive testing; calibration blocks; measurement uncertainty.
FAQ
Q: What is this standard?
A: PNAE G-7-031-91 is a technical normative document that defines unified ultrasonic methods for measuring the thickness of mono‑ and bimetallic products and anti‑corrosion coatings used on equipment and piping of nuclear power plants. It is Part III in a series of ultrasonic control procedures for nuclear plant materials.
Q: What does it cover?
A: It covers the ultrasonic echo‑pulse measurement method, required instruments and calibration blocks, measurement procedures and sampling, statistical treatment of measurement errors, personnel attestation, documentation of results and limitations of the method for various geometries and corrosion types.
Q: Who typically uses it?
A: Nondestructive testing specialists, QC/inspection engineers, plant maintenance teams, equipment manufacturers and regulatory inspectors in the nuclear power sector use the document as a procedural and technical reference when performing thickness measurements on plant components.
Q: Is it current or superseded?
A: The standard was approved 31 October 1991 and came into force 1 October 1992, but it was withdrawn (ceased to be applicable) by Rostekhnadzor order No. 360 dated 13 August 2018. It should be treated as cancelled and replaced by later regulatory or technical documents issued by the supervisory authority; users must consult current regulatory lists to determine applicable replacements.
Q: Is it part of a series?
A: Yes — it is Part III of a set of unified control methodologies for base materials, welds and surfacings in nuclear power plant equipment and piping (the PNAE G-7 series). Related parts include PNAE G-7-014-89 (Part I) and PNAE G-7-030-91 (Part II).
Q: What are the key keywords?
A: Ultrasonic thickness measurement; echo‑pulse method; monometal; bimetal; cladding; anti‑corrosion coating; PNAE G‑7; nuclear power plant; NDT; calibration blocks; measurement uncertainty.