Overview
ISO 24390:2023 - "Nuclear energy - Nuclear fuel technology - Methodologies for radioactivity characterization of very low-level waste (VLLW) generated by nuclear facilities" provides standardized methodologies to characterize radioactivity in very low-level waste (VLLW) produced during operation or decommissioning of nuclear facilities. The standard focuses on radioactive solid waste and is intended to differentiate VLLW from higher-level low-level waste (LLW) and from waste below clearance levels. It supports demonstrating that waste meets waste acceptance criteria (WAC) for near-surface landfill-type disposal or alternative routes. Clearance/exemption monitoring and liquid or gaseous waste characterization are explicitly excluded.
Key topics and technical requirements
- Waste Acceptance Criteria (WAC): Defines radiological, physical, chemical and package-related criteria that VLLW must meet for acceptance by disposal or processing facilities. WAC should be measurable, verifiable and justified (e.g., via DQO).
- Radioactivity characterization process: A multi-step approach detailed in the standard, including:
- Step 1 - Investigation of waste characteristics
- Step 2 - Surface scanning (NDA in situ)
- Step 3 - Gamma activity measurement
- Step 4 - Destructive analysis (laboratory radiochemical/chemical methods)
- Measurement methodologies: Use of non-destructive analysis (NDA) for in situ gamma-emitting nuclides and destructive analysis (e.g., radiochemistry, ICP‑MS) for difficult-to-measure (DTM) radionuclides.
- Correlation methods: Guidance on scaling factor and nuclide vector approaches to infer DTM radionuclide activity from key (gamma) radionuclides.
- Sampling strategies: Procedures for homogeneous vs heterogeneous waste, and quantification of sampling uncertainty.
- Decision thresholds and data quality: Definition of decision thresholds, data quality objectives (DQO) and quality assurance provisions for labs, instruments, personnel and documentation.
- Quality Assurance: Requirements for traceability, QA/QC, and documented procedures.
Practical applications and users
ISO 24390:2023 is primarily used by:
- Nuclear facility operators and decommissioning teams for waste classification and routing.
- Radioactive waste managers and disposal site operators to define and verify WAC compliance.
- Analytical laboratories performing destructive assays for DTM radionuclides.
- Regulators and safety assessors evaluating waste acceptance, environmental protection and public safety.
- Consultants designing characterization programs and sampling plans.
Benefits include improved consistency in VLLW classification, defensible measurement strategies, optimized waste routing (including potential reuse/recycling), and enhanced protection of people and the environment.
Related standards
Keywords: ISO 24390:2023, VLLW, very low-level waste, radioactivity characterization, waste acceptance criteria, non-destructive analysis, destructive analysis, scaling factor, nuclide vector, nuclear decommissioning.
Open preview (PDF)Nuclear energy — Nuclear fuel technology — Methodologies for radioactivity characterization of very low-level waste (VLLW) generated by nuclear facilities