Stabilisation/solidification of Radionuclides Polluted Soils: a Novel Analytical Approach for the Assessment of the γ-radiation Shielding Capacity

Soil contamination caused by γ-radiation emitter radionuclides is a serious problem worldwide. Cementbased Stabilisation/solidification (S/S) could represent an optimal choice to treat radionuclides polluted soils due to the possibility to shield the γ-radiation emitted by contaminant. In order to better planning the treatment procedures, a novel analytical approach has been developed and applied in order to assess the γ-radiation shielding (γRS) of cylindrical S/S treated bodies taking into account the shielding properties of materials used in S/S treatment, all the parameters related to nuclear processes involved and the interaction between radiation and matter. Calculations were compared with γRS values obtained by bench-scale experimental activities. For experiments a soil spiked by thorium oxide (ThO2) was stabilised/solidified using different binder mixture of Portland cement and barite aggregates at different soil:binder ratios and tested for its γ-radiation shielding properties. Results obtained showed that the presence of the barite aggregates mixed with cement gives a significant containment of the γ-radiation possibly representing an optimal choice to S/S treat low level radionuclides polluted soil. Furthermore, a good correspondence between analytical and experimental data was observed making the proposed analytical approach a potential suitable tool to great simplify the estimation of γ-radiation shielding properties of several binders-materials-radionuclides S/S systems.