ISO 15366-1:2014

Overview

ISO 15366-1:2014 - "Nuclear fuel technology - Chemical separation and purification of uranium and plutonium in nitric acid solutions for isotopic and isotopic dilution analysis by solvent extraction chromatography - Part 1" specifies a validated chromatographic procedure to separate and purify uranium (U) and plutonium (Pu) from dissolved irradiated light‑water reactor fuel and high active liquid waste prior to isotopic measurement. The method is optimized for samples containing Pu 1 µg–150 µg and U 0.1 mg–2 mg in up to 2 ml of 3 mol·L⁻¹ HNO3, with U/Pu ratios from 0 up to 200.

Key topics and technical requirements

• Separation principle: column extraction chromatography using tri‑n‑octylphosphine oxide (TOPO) coated on silica gel; selective retention of Pu(IV) and U(VI) from 3 mol·L⁻¹ nitric acid.
• Valency control: redox valency cycle using Fe(II) sulfate and sodium nitrite to set Pu to the tetravalent state before separation.
• Column and reagents:
  • Disposable polypropylene or glass columns packed with TOPO‑coated silica gel.
  • Elution scheme: condition with formic acid, elute Pu after reduction with ascorbic acid, and elute U with ammonium carbamate.
• Operational constraints:
  • Column gravity flow rate should not exceed 0.1 ml·min⁻¹ to ensure reaction kinetics.
  • Column capacity ~15 mg U; typical element recoveries 80–90% for both U and Pu in the stated ranges.
  • Decontamination factors for cross‑contamination between U and Pu of the order of 10 or better; Pu fractions typically contain <0.001% Am by mass fraction.
• Quality control:
  • Run blanks and control samples (spiked/certified solutions) in parallel and monitor via isotope dilution mass spectrometry and alpha spectrometry.
  • Use control charts to track blank contributions and recoveries.

Practical applications and who uses this standard

ISO 15366-1:2014 is intended for analytical laboratories involved in:

• Isotopic and isotope‑dilution analysis by mass spectrometry (ISO 8299 referenced) and alpha spectrometry (ISO 11483 referenced).
• Chemical characterization of dissolved spent nuclear fuel and high active liquid waste from reprocessing facilities.
• Analytical support for research in nuclear fuel technology and routine assays in reprocessing plant laboratories.

The standard provides a reproducible, robust procedure suitable for routine lab workflows, including robotized column operation with disposable columns.

Related standards

• ISO 8299 - Sample preparation and isotope dilution mass spectrometric analysis (referenced for mass spectrometry measurement practices).
• ISO 11483 - Alpha spectrometry methods (referenced for Pu isotopic/alpha measurements).

Keywords: ISO 15366-1:2014, uranium plutonium separation, solvent extraction chromatography, TOPO, isotopic analysis, mass spectrometry, alpha spectrometry, spent fuel reprocessing.