NP 104-18 PDF

Full title and description

NP 104-18 — Federal rules and regulations in the field of the use of atomic energy: "Welding and surfacing (overlay welding) of equipment and pipelines of nuclear power installations". This document establishes mandatory technical and quality requirements for welding and surfacing activities applied to components, equipment and piping used at nuclear installations.

Abstract

NP 104-18 defines requirements for selection and qualification of welding and surfacing methods and materials, preparation and assembly for welding, types of welded joints, heat treatment of welded joints and overlaid parts, quality control of welding and surfacing materials, non‑destructive and destructive testing, procedures for defect correction, documentation and passporting of equipment and welded assemblies. The standard replaces earlier PNAE G-7-009-89 and is intended to ensure the integrity and long‑term reliability of welded structures in nuclear power installations.

General information

• Status: Active / in force.
• Publication date: Approved by Rostechnadzor Order No. 554 on 14 November 2018; entered into force 6 January 2019.
• Publisher: Federal Service for Environmental, Technological and Nuclear Supervision (Rostechnadzor).
• ICS / categories: Welding and allied processes (ICS 25.160); Nuclear energy engineering / nuclear power plants (ICS 27.120).
• Edition / version: Original approval 2018 (NP-104-18); amendments published by Rostechnadzor (notably Order No. 538, 16 December 2020 — registered April 2021 — and Order No. 210, 8 July 2024, amendment published August 2024 and effective 31 August 2024). Consolidated (amended) editions incorporate the 2020 and 2024 changes.
• Number of pages: Main official text commonly distributed as 46 pages (core adopted text); some consolidated/annotated or translated editions and vendor reproductions report longer page counts (varies by edition/translation, reported examples: 46 — 76 — 268 pages).

Scope

NP 104-18 applies to manufacture, installation and repair of equipment and pipelines of nuclear power installations and sets mandatory rules for welding and surfacing activities that affect nuclear safety and integrity of pressure‑bearing and safety‑related components. The document includes requirements on welding consumables and materials, welding equipment and technology, assembly and fit‑up, welding procedure specification and qualification, welder/operation qualification, heat treatment, testing (NDT and destructive), acceptance criteria, defect repair and documentation (equipment passport and welding records). Certain specific plant items or reactor types may be excluded or addressed by separate rules or later amendments as noted in the text and amendment notices.

Key topics and requirements

• Requirements for selection and qualification of welding and surfacing methods and consumables (materials, electrodes, filler metals).
• Welding procedure specification (WPS) development and qualification; attestation testing of welding technologies for nuclear applications.
• Qualification and certification requirements for welders, operators and personnel performing overlay welding.
• Preparation, assembly, fit‑up, permissible joint types and dimensional controls for nuclear equipment and piping.
• Pre‑ and post‑weld heat treatment (PWHT) regimes and thermal treatment controls.
• Non‑destructive examination (NDE) and destructive testing requirements and acceptance criteria specific to nuclear safety applications.
• Control of welding/surfacing materials and traceability; documentation and equipment passport requirements.
• Procedures and controls for defect detection, repair (remedial welding/overlay) and re‑examination.
• Requirements for demonstrating long‑term behaviour (creep, irradiation effects) and mechanical properties for welded/overlaid joints where applicable.

Typical use and users

Primary users are nuclear operators, plant designers, equipment manufacturers, fabricators and maintenance contractors working on nuclear power plants, as well as regulatory and inspection bodies, welding engineers, materials specialists and NDT/QA organisations. NP 104-18 is used for design acceptance, procurement specifications, fabrication and in‑service repair planning for welded and overlaid components crucial to nuclear safety.

Related standards

NP 104-18 replaces the earlier PNAE G-7-009-89 and is referenced alongside other national standards and GOST/ГОСТ R documents and nuclear rules (examples: ГОСТ Р 58721-2019, ГОСТ Р 59023.1-2020 and related parts on welding materials and procedures, and NP-089-15 for equipment and pipeline rules). It is also applied together with quality and conformity assessment standards used in the nuclear supply chain.

Keywords

welding; surfacing; overlay welding; nuclear power; pipelines; equipment; welder qualification; welding procedure; NDE; heat treatment; defect repair; Rostechnadzor; NP-104-18.

FAQ

Q: What is this standard?

A: NP 104-18 is a Russian federal rules-and-regulations document that sets mandatory requirements for welding and surfacing (overlay welding) of equipment and pipelines used in nuclear power installations; it was approved by Rostechnadzor in 2018 and came into force in January 2019.

Q: What does it cover?

A: It covers welding methods and consumables, welding procedure and personnel qualification, pre/post‑weld thermal treatment, preparation and assembly for welding, types of welded joints, material control, testing (NDT/destructive), repair of defects, documentation and verification required to ensure the integrity of welded structures in nuclear installations.

Q: Who typically uses it?

A: Nuclear plant owners/operators, designers, fabricators, maintenance and repair contractors, welding and materials engineers, NDT/QA providers and regulatory/inspection authorities use NP 104-18 as a mandatory technical reference for nuclear welding and surfacing activities.

Q: Is it current or superseded?

A: NP 104-18 is current (in force). It superseded PNAE G-7-009-89 and has been amended since issuance (notably by Rostechnadzor orders in 2020 and 2024); users should consult the consolidated (amended) text applicable to the date of work or procurement.

Q: Is it part of a series?

A: Yes — NP‑series federal rules govern various aspects of equipment, pipelines and safe operation of nuclear installations (for example NP‑089‑15 and NP‑105‑18 are related documents). NP 104-18 interacts with other national nuclear rules and applicable GOST/ГОСТ R standards.

Q: What are the key keywords?

A: welding; surfacing; overlay welding; nuclear installations; welding qualification; welding materials; NDT; heat treatment; defect repair; equipment passport.