Batch sorption experiments of cesium and strontium on crushed rock and biotite for the estimation of distribution coefficients on intact crystalline rock.

The distribution coefficient (K) of radionuclides on bedrock is one of the key parameters used in the safety analysis of spent nuclear fuel repositories. Typically, distribution coefficients have been determined using crushed rock. However, recent studies have shown that crushing of the rock increases considerably the distribution coefficient compared with the values of intact rock.

Electromigration experiments for studying transport parameters and sorption of cesium and strontium on intact crystalline rock.

This study aims to determine upscaling factors for the radionuclides' distribution coefficients (K) on crushed rocks to intact rock for the safety analysis of radionuclide migration from spent nuclear fuel in bedrock towards biosphere. Here we report the distribution coefficients for intact rock determined by electromigration sorption experiments and compare the results with those from recently performed batch sorption experiments. In total 34 rock samples, representing three typical rock types from Olkiluoto Finland, were studied in order to determine distribution coefficients, effective diffusion coefficients and porosities using the electromigration sorption experiments, formation factor experiments and porosity measurement.

Radon emanation from fresh, altered and disturbed granitic rock characterized by C-PMMA impregnation and autoradiography.

Radon emanation from intact samples of fresh ("BG"), altered ("Fract") and disturbed ("EDZ") Finnish granitic rock from Kuru (Finland) and its dependence on humidity and rock structural factors was studied. The pore network of the rock was characterized by microscopy and impregnation with C-PMMA (polymethylmethacrylate) resin and autoradiography. The radon emanation factor was increasing linearly with the relative humidity.