ISO 12749-3:2024

Overview - ISO 12749-3:2024 (Vocabulary for nuclear installations, processes and technologies)

ISO 12749-3:2024 is the second edition of the ISO vocabulary for nuclear energy, nuclear technologies and radiological protection focused on nuclear installations, processes and technologies. It standardizes terms and definitions used across standards and technical documents that relate to the planning, design, construction, operation and decommissioning of facilities and processes involving radioactive materials. The document was prepared by ISO/TC 85 and draws on technically validated sources such as IAEA publications. Annex A documents the methodology used to develop the vocabulary.

Key topics and technical coverage

This part of the ISO 12749 vocabulary organizes terminological data into concept systems to promote unambiguous communication. Major subject areas include:

• Nuclear materials and fuels (definitions for nuclear material, fissile/fissionable nuclides, burnup, fuel element, cladding)
• Nuclear fuel cycle concepts (fuel fabrication, handling and related terms)
• Ex‑reactor nuclear criticality safety (critical, subcriticality, subcriticality limits and dimensions, neutron absorber, over‑batching)
• Analytical methodologies and measurements (attenuation, attenuation correction factor, non‑destructive analysis concepts)
• Transport of radioactive materials terminology
• Materials characterization and permeation concepts
• Radioactive waste management and decommissioning terms and definitions

The standard clarifies excluded topics to avoid overlap, for example sealed sources, radiation processing, non‑peaceful applications, and in certain respects nuclear power plants and research reactors (specifically nuclear criticality safety while fuel is loaded in the reactor core).

Practical applications and intended users

ISO 12749-3:2024 is intended for anyone who needs consistent nuclear terminology to develop, interpret or apply standards, manage regulatory compliance, or communicate across organizations. Typical users include:

• Standards writers and technical committees (ISO/TC 85 and others)
• Nuclear engineers and designers (fuel cycle, decommissioning, waste management)
• Safety analysts and criticality safety specialists
• Regulators and licensing authorities
• Transport and packaging professionals for radioactive materials
• Laboratory staff and NDA (non‑destructive analysis) practitioners
• Educators, translators and legal/compliance teams working on contracts and specifications

Practical uses: harmonizing specifications, reducing misinterpretation in safety cases and regulatory submissions, drafting procurement documents, training materials and multinational collaboration.

Related standards and sources

ISO 12749-3 references and aligns terminology with other standards and technical documents, including:

• Other parts of the ISO 12749 series (e.g., ISO 12749-1)
• ISO 1709, ISO 21391, ISO 19017, ISO 12807 (terminology and measurement concepts cited in the text)
• IAEA Nuclear Safety and Security Glossary and other IAEA documents

ISO 12749-3:2024 helps improve clarity and interoperability across nuclear‑sector standards by providing a harmonized vocabulary for installations, processes and technologies involving radioactive materials.