90Sr migration to the geo-sphere from a waste burial in the Chernobyl exclusion zone

Title: 90Sr migration to the geo-sphere from a waste burial in the Chernobyl exclusion zone

Author: L Dewiere, D Bugai, C Grenier, V Kashparov, N Ahamdach

Reference: Journal of Environmental Radioactivity, Volume 74, Issues 1–3, 2004, Pages 139-150

DOI: http://dx.doi.org/10.1016/j.jenvrad.2004.01.019

Keywords: Chernobyl; Strontium-90; Fuel particles; Groundwater; Retardation; Sorption; Hydro-dispersion

Abstract: Results are presented from an ongoing field-scale experimental study (namely the Chernobyl Pilot Site project) aimed at characterization of processes controlling ⁹⁰Sr releases from a shallow trench containing nuclear fuel particles, and subsequent radionuclide transport in the underlying sandy aquifer at the Chernobyl nuclear power plant site. Microscopic analyses of waste material and leaching experiments have shown that 10–30% of the radioactive inventory is associated with chemically extra-stable Zr–U–O particles. The largest fraction of ⁹⁰Sr activity in the trench (≈30–60%) is currently associated with relatively slowly dissolving non-oxidized UO₂ matrix fuel particles. The ⁹⁰Sr migration velocity in the eolian sand aquifer is retarded by sorption to ≈9% of groundwater flow velocity (K_d ≈ 2 ml/g). The dispersivity values for non-reactive solute transport in the aquifer predicted by geostatistics (i.e. 0.8 6 cm) were confirmed by a natural gradient tracer test using ³⁶Cl. The observed negative correlation between hydraulic conductivity and K_d of aquifer sediments suggests that ⁹⁰Sr could be subjected to larger dispersion in the subsurface compared with ³⁶Cl.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X04000244