STO 79814898 110-2012 PDF

Full title and description

STO 79814898 110-2012 — Parts and elements of pipelines of nuclear power plants made of corrosion‑resistant (austenitic) steel for pressure up to 2.2 MPa (22 kgf/cm²). Welded joints — types and dimensions. The document specifies types and sizes of welded butt and corner joints, welding methods and materials, edge preparation and completed‑seam dimensions used in NPP pipeline assemblies.

Abstract

This organizational standard gives mandatory recommendations for the design and manufacture of welded connections for pipeline parts and fittings used in nuclear power plants (NPPs) where corrosion‑resistant austenitic steels are employed for service pressures up to 2.2 MPa. It defines joint types, dimensional series, welding materials and procedures, fit‑up tolerances and acceptance dimensions to ensure interchangeability and compliance with nuclear regulatory rules.

General information

• Status: Active (organizational standard in force; supersedes STO 79814898 110-2009).
• Publication date: Approved 25 December 2012; introduced into effect 1 January 2013 (year 2012 edition).
• Publisher: Standard of organization (JSC Institute "Sevzapenergomontazhproekt" — developed and approved by that Institute; adopted with participation of Atomenergoproekt and other industry parties).
• ICS / categories: OKS / classification shown in the document: 23.040.01; 27.120.01 — falls under ICS 27.120 (nuclear energy engineering / nuclear power plants).
• Edition / version: 2012 edition (replaces STO 79814898 110-2009).
• Number of pages: Approximately 30 pages (electronic / PDF distribution count).

Scope

The standard applies to welded butt and corner joints used for assembly of pipelines and pipeline blocks of nuclear power plants constructed from austenitic corrosion‑resistant steels for operating pressures up to 2.2 MPa (22 kgf/cm²). It is intended for pipelines classified by the PNAE G‑7‑008 rules in groups B and C and for connections between these pipelines and equipment, valves and pipelines made of pearlitic steels. The document may also be used for design and manufacture of similar NPP pipelines except those classified in group A by PNAE G‑7‑008.

Key topics and requirements

• Definition and graphical representation of standard welded joint types (butt and corner joints) and their dimensional series.
• Welding methods and selection of welding consumables suitable for austenitic corrosion‑resistant steels in NPP service.
• Edge preparation forms, groove geometries and root/opening dimensions for repeatable fit‑up.
• Tolerances and allowable misalignment (fit‑up tolerances, limit deviations and permissible offsets) relevant to final seam geometry.
• Finished‑seam dimensions and inspection/acceptance criteria for welded joints used in pipeline assemblies.
• Normative references and cross‑references to other parts of the STO series and to regulatory rules for NPP equipment and pipelines.

Typical use and users

Primary users are NPP design institutes, pipeline and component designers, fabricators and manufacturers of welded pipeline fittings for nuclear power plants, welding technologists and procedure developers, quality assurance / inspection teams, and regulatory or certification bodies engaged in nuclear mechanical systems. The standard is used during design specifying, fabrication drawings, welding procedure specification (WPS) development, shop production and QA acceptance.

Related standards

Part of the STO 79814898 series for NPP pipeline parts and fittings. Related organizational and national documents referenced by the standard include earlier STO 79814898 110-2009 (superseded), STO 79814898 108-2009 (technical requirements), STO 79814898 111-2009 (tight‑bend elbows), STO 79814898 127-2009 and 126-2009 (tees), and relevant GOSTs and PNAE regulatory rules (PNAE G‑7‑008).

Keywords

STO 79814898 110-2012; welded joints; pipeline parts; nuclear power plant pipelines; corrosion‑resistant steel; austenitic steel; butt joint; corner joint; groove preparation; fit‑up tolerances; 2.2 MPa; PNAE G‑7‑008.

FAQ

Q: What is this standard?

A: STO 79814898 110-2012 is an organizational standard that specifies types, dimensions and requirements for welded joints of pipeline parts and fittings made of corrosion‑resistant austenitic steels for nuclear power plant pipelines up to 2.2 MPa.

Q: What does it cover?

A: It covers welded butt and corner joints (drawings and dimensional series), recommended welding methods and consumables, edge/groove preparations, fit‑up tolerances, finished seam dimensions and references to applicable regulatory documents for NPP pipeline groups B and C.

Q: Who typically uses it?

A: Pipeline designers and fabricators for nuclear power plants, welding engineers, QA/QC inspectors, procurement specialists specifying parts and components for NPP mechanical systems, and design institutes involved in NPP piping systems.

Q: Is it current or superseded?

A: The 2012 edition is shown as in force (active) and it replaces the 2009 edition (STO 79814898 110-2009). Users should check the issuing organization’s current registry or the annually updated lists for any amendments.

Q: Is it part of a series?

A: Yes — it is one part of the STO 79814898 family of organizational standards that define designs and dimensions for various pipeline fittings and elements for NPPs (other parts cover elbows, tees, technical requirements, etc.).

Q: What are the key keywords?

A: Welded joints; pipeline fittings; corrosion‑resistant / austenitic steel; nuclear power plant pipelines; groove preparation; fit‑up tolerances; 2.2 MPa; STO 79814898.