Overview
EN ISO 8299:2021 (identical to ISO 8299:2019) defines a validated analytical method for the determination of isotopic and elemental uranium and plutonium concentrations in nitric acid solutions using thermal‑ionization mass spectrometry (TIMS). This nuclear fuel technology standard covers sample types and measurement workflows used in fuel reprocessing, fuel fabrication and irradiated fuel assays. It is published by CEN/ISO and intended for laboratories performing quantitative isotopic assays of U and Pu in nitric acid matrices.
Key Topics
- Principle: Isotope and elemental assay of U and Pu by TIMS (thermal‑ionization mass spectrometry).
- Scope of applicability: Irradiated Magnox and light water reactor (BWR, PWR) fuels, final products at spent‑fuel reprocessing plants, and feed/products of MOX and uranium fuel fabrication. Adaptable to other fuel types with modified chemical separation and spike solutions.
- Reference materials & spikes: Use and preparation of spike and reference materials for isotope dilution techniques (Annex A addresses spike standardization).
- Chemistry & separation: Reagents, ion‑exchange and extraction resins, valence adjustment methods and purification procedures to isolate U and Pu from nitric acid solutions.
- Sample handling: Subsampling, spiking, treatment of pellets, powders, concentrated reprocessing solutions, plutonium nitrate solutions and dried nitrates.
- Filament & TIMS setup: Filament preparation and loading techniques, filament assemblies and degassing for reliable TIMS ionization.
- Instrument calibration & measurement: Mass and detector calibration (including Faraday gain), mass discrimination corrections, total evaporation and bias‑correction measurement modes.
- Data reduction & quality: Calculation of isotope abundances and concentrations, decay correction, blanks, quality control, measurement uncertainty and known interferences.
Applications / Who Uses It
- Nuclear analytical and quality control laboratories at spent‑fuel reprocessing plants, MOX and uranium fuel fabrication facilities.
- Research laboratories and laboratories supporting nuclear safeguards, accountancy and forensic investigations that require accurate isotopic and elemental assays.
- Regulatory and compliance testing where standardized, reproducible TIMS methods for U/Pu in nitric acid solutions are required.
Related Standards
- Developed by ISO/TC 85 and adopted by CEN/TC 430; users should consult other ISO/CEN standards and technical reports on nuclear materials analysis and radiochemical procedures for complementary methods, instrument performance and laboratory accreditation guidance.
Keywords: EN ISO 8299:2021, ISO 8299:2019, thermal‑ionization mass spectrometry, TIMS, uranium plutonium isotopic analysis, nitric acid solutions, nuclear fuel technology, spent‑fuel reprocessing, MOX, Magnox, light water reactor.
