EN ISO 15366-1:2016 PDF

Overview

EN ISO 15366-1:2016 (ISO 15366-1:2014) specifies a validated radiochemical procedure for the chemical separation and purification of uranium and plutonium from nitric acid solutions using solvent extraction chromatography. It is designed for samples from irradiated light‑water reactor fuel dissolutions and high‑activity liquid wastes from reprocessing plants, prior to isotopic analysis (e.g., mass spectrometry or alpha spectrometry).

Key scope points:

• Applies to samples containing 1 μg to 150 μg Pu (IV/V/VI) and 0.1 mg to 2 mg U (IV/VI) in up to 2 ml of 3 mol·L⁻¹ HNO3.
• Applicable for mixtures with U/Pu ratios from 0 up to 200.
• Endorsed by CEN as a European standard (EN ISO 15366-1:2016).

Key topics and technical requirements

• Separation principle: Column extraction chromatography using tri‑n‑octylphosphine oxide (TOPO) coated on an inert silica support to selectively extract Pu(IV) and U(VI) from 3 mol·L⁻¹ nitric acid.
• Valency control: Redox valency adjustment is performed (iron(II) sulfate and sodium nitrite) to ensure plutonium is in the tetravalent state before separation; subsequent controlled reduction and elution steps recover separated fractions.
• Elution chemistry:
  • Plutonium is eluted after reduction (e.g., with ascorbic acid) and can be measured by alpha spectrometry as a check on recovery and to complement mass spectrometric results.
  • Uranium is eluted using ammonium carbamate solution.
• Apparatus and consumables: Disposable polypropylene or glass columns with specified bed volume and frit porosity; silica gel particle size and TOPO loading detailed in Annex A.
• Analytical controls: Parallel blanks and certified control samples are required to monitor cross‑contamination, recovery efficiency and correct isotopic equilibration.
• Operational limits: Gravity column flow rates recommended not to exceed 0.1 mL·min⁻¹ to ensure favourable kinetics.
• Reagents and safety: Use analytical grade reagents and deionized water; note flammability of TOPO in cyclohexane and handling restrictions for radioactive materials.

Applications and users

This standard is directly applicable to:

• Nuclear fuel technology and spent fuel reprocessing laboratories.
• Radiochemistry and isotopic analysis facilities performing uranium/plutonium assay by mass spectrometry or alpha spectrometry.
• Nuclear safeguards, environmental monitoring, and R&D groups needing reliable U/Pu separation for isotopic dilution and isotopic composition measurement.

Related standards

• ISO 15366-2 (Part 2): procedure for nanogram and sub‑nanogram level samples.
• ISO 8299 and ISO 11483: referenced for isotopic measurement methods (mass spectrometry and alpha spectrometry).

Keywords: EN ISO 15366-1:2016, ISO 15366-1:2014, nuclear fuel technology, uranium plutonium separation, solvent extraction chromatography, TOPO, nitric acid solutions, isotopic analysis, mass spectrometry, alpha spectrometry.