ISO 18229:2018

Overview

ISO 18229:2018 - "Essential technical requirements for mechanical components and metallic structures foreseen for Generation IV nuclear reactors" - defines the essential design and construction requirements for mechanical and metallic components used in Generation IV (GEN IV) nuclear reactors. The standard addresses components that are important for nuclear safety and prevention of radioactive release (e.g., vessels, pumps, valves, pipes, bellows, heat exchangers and handling mechanisms). It covers six GEN IV concepts (sodium fast, lead fast, gas fast, very high temperature, supercritical water and molten salt reactors) and focuses on design and fabrication phases; it explicitly excludes operation, maintenance and in‑service inspection.

Key Topics

• Scope and principles: Defines safety‑oriented limits and the interface with national codes - intended to complement, not replace, existing design codes.
• Management system: Requirements for quality, documentation and supplier declarations to support conformity assessment.
• Materials: Material specification, traceability and conformity declaration; includes guidance (see Annex B) on material selection for specific GEN IV concepts.
• Design: Rules covering damage considerations, operating conditions and load combinations, corrosion/erosion/wear, attachments, thermal ageing and irradiation effects, and criteria levels for safety classification.
• Fabrication: Requirements for identification, preparation, welding, forming tolerances, heat treatment and cleaning to ensure component integrity.
• Tests and examinations: Qualified methods, personnel requirements, inspection procedures and final pressure testing.
• Final inspection & documentation: Marking/labelling, documentation deliverables and conformity assessment (references ISO/IEC 17050‑1).
• Informative annexes: Annex A (GEN IV concept characteristics), Annex B (material selection for SFR), Annex C (types of damage), Annex D (recommended documentation).

Applications

• Who uses it: Reactor designers, manufacturers, fabricators, project owners, regulatory bodies and procurement teams involved in GEN IV reactor projects.
• How it is used: As a high‑level requirements framework to ensure mechanical components and metallic structures meet GEN IV safety objectives during design and construction, to inform equipment specifications, supplier qualifications, inspection plans and conformity assessments.
• Practical value: Helps harmonize safety expectations across international projects, supports selection of materials and fabrication processes resistant to high temperatures, irradiation and corrosive coolants, and clarifies documentation and testing needed for regulatory submission.

Related Standards

• ISO/IEC 17050‑1 (Supplier’s declaration of conformity) is referenced for conformity assessment. ISO 18229:2018 is intended to work alongside established national and international codes used for nuclear pressure equipment and fabrication.