Overview
ISO 12749-5:2018 - "Nuclear energy, nuclear technologies, and radiological protection - Vocabulary - Part 5: Nuclear reactors" is an international vocabulary that defines core terms and concepts used across the field of nuclear reactors. The standard collects terms, definitions, notes and examples for reactor-related concepts at a broad, non‑quantitative level. It is intended to promote clear communication and a common understanding among engineers, regulators, researchers and other stakeholders working with nuclear reactors.
Key characteristics:
- Provides minimum essential information for each nuclear reactor concept.
- Excludes quantitative data (no numerical specifications or performance limits).
- Organizes entries in a conceptual (preferred-term) order and includes systematic and alphabetical indexes.
- Includes an informative Annex A (methodology) and a bibliography.
Key topics
ISO 12749-5:2018 covers foundational nuclear reactor vocabulary, including but not limited to:
- Nuclear fission (spontaneous and induced) and fission energy
- Prompt and delayed fission neutrons and fission radiation
- Fission products, fast and thermal neutrons
- Fissile and fertile nuclides
- Nuclear chain reaction, controlled chain reaction, and nuclear criticality
- Effective neutron multiplication factor (keff) and reactivity (ρ)
- Poison (neutron absorbers), neutron multiplicative configuration, and reactor kinetics
- Notes and examples to clarify ambiguous or widely misunderstood terms
The standard draws on established sources (ISO/TC 85 materials, IAEA, IEC) and documents terminological consensus from subject‑matter experts.
Applications
ISO 12749-5:2018 is practical for any activity that requires precise, unambiguous terminology related to nuclear reactors:
- Technical documentation, procedures and operating manuals
- Regulatory guidance, licensing documents and safety cases
- Standards development and cross‑organization coordination
- Training materials, textbooks and translator/reference glossaries
- Communication between multidisciplinary teams (design, operations, safety, procurement)
Because the vocabulary excludes quantitative specifications, it is complementary to technical standards that set numerical requirements.
Who should use it
- Nuclear engineers and reactor physicists
- Regulatory bodies and safety analysts
- Standards writers and technical editors
- Educators, trainers and translators working in nuclear technology
- Project managers and procurement specialists who need consistent terminology
Related standards
- Part of the ISO 12749 series (vocabulary for nuclear energy and radiological protection)
- Cross-references to ISO/TC 85 publications and IAEA terminology resources are included in the bibliography
Using ISO 12749-5:2018 helps reduce ambiguity, improve documentation quality, and ensure consistent use of core nuclear reactor terms across international projects and regulatory frameworks.
Open preview (PDF)Nuclear energy, nuclear technologies, and radiological protection — Vocabulary — Part 5: Nuclear reactors
