Silicon isotope ratio measurements by inductively coupled plasma tandem mass spectrometry for alteration studies of nuclear waste glasses.

High-level, long-lived nuclear waste arising from spent fuel reprocessing is vitrified in silicate glasses for final disposal in deep geologic formations. In order to better understand the mechanisms driving glass dissolution, glass alteration studies, based on silicon isotope ratio monitoring of Si-doped aqueous solutions, were carried out in laboratories. This work explores the capabilities of the new type of quadrupole-based ICP-MS, the Agilent 8800 tandem quadrupole ICP-MS/MS, for accurate silicon isotope ratio determination for alteration studies of nuclear waste glasses.

Estimation of sedimentation rates based on the excess of radium 228 in granitic reservoir sediments.

Knowledge of sedimentation rates in lakes is required to understand and quantify the geochemical processes involved in scavenging and remobilization of contaminants at the Sediment-Water Interface (SWI). The well-known Pb excess (Pb) method cannot be used for quantifying sedimentation rates in uranium-enriched catchments, as large amounts of Pb produced by weathering and human activities may dilute the atmospheric Pb. As an alternative dating method in these cases, we propose an original method based on Th decay series nuclides.

High (36)Cl/Cl ratios in Chernobyl groundwater.

After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A (90)Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, (36)Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater.