Application of the isotope dilution technique for Zr-93 determination in an irradiated cladding material by multiple collector-inductively coupled plasma mass spectrometry

摘要

The determination of Zr-93 concentration, a long-lived radionuclide present in spent nuclear fuel and in the structural components of nuclear reactors, is a major issue for nuclear waste disposal purpose and to validate neutronic calculation codes. To measure Zr-93 concentration in irradiated cladding material with a high precision, an analytical method based on the use of multiple collector-inductively coupled plasma mass spectrometer (MC-ICPMS) combined to isotope dilution technique was developed. First a radiochemical separation of zirconium from a zircaloy sample (a zirconium alloy used as a cladding material for nuclear fuel elements), has allowed to obtain a very pure zirconium fraction with no potential isobaric interferences for mass spectrometric measurements. Then as the determination of all zirconium isotope ratios in the sample is necessary for the isotope dilution method, a MC-ICPMS procedure was developed to perform these precise measurements. Finally, the determination of Zr-93 concentration in the same sample was performed, after preparation and calibration of a Zr-96 spike solution. The uncertainties obtained on isotope ratios of zirconium by MC-ICPMS were in the order of 0.1%. The final uncertainty obtained on the Zr-93 concentration in the nuclear material used and after chemical purification was lower than 0.6%. (C) 2007 Elsevier B.V. All rights reserved.