ABSTRACT
Sorption is an important process for the transport of radionuclides through backfill materials in a radioactive waste underground repository. Within this study, sorption of Cs on selected Czech clay materials and their mixtures with sand was investigated by batch tests. The experiments were performed under oxic conditions at 25 degrees C. Synthetic groundwater as a liquid phase and unconditioned clays (as they were provided by their producer) were used to reach the natural conditions as close as possible. Distribution ratios (Rds) of Cs for all selected clays rise with increase of the clay fraction in clay/sand mixtures in agreement with previous works studying sorption behaviour of such mixtures. The rise of Rds is from 10(2) cm3 g(-1) for mixtures with 80% of sand to 10(3) cm3 g(-1) for pure clays. There are significant differences between natural and technologically modified clays.
Subject(s)
Aluminum Silicates/chemistry , Cesium Radioisotopes/analysis , Cesium Radioisotopes/chemistry , Silicates/chemistry , Silicon Dioxide/chemistry , Soil Pollutants, Radioactive/analysis , Adsorption , Aluminum Silicates/analysis , Clay , Complex Mixtures/analysis , Complex Mixtures/chemistry , Czech Republic , Diffusion , Environmental Monitoring/methods , Radiometry/methods , Silicon Dioxide/analysisSubject(s)
Tooth Eruption , Adolescent , Birth Weight , Body Weight , Breast Feeding , Child , Education , Female , Humans , Male , Mothers , Skull/anatomy & histologyABSTRACT
On the basis of these findings, we have concluded that the surgeon contemplating the construction of a mesocaval shunt can expect to find ideal or nearly ideal conditions in approximately one third of the population. Another two thirds can be expected to present anatomical variations which may complicate the procedure in varying degrees. In approximately one tenth of the cases, the construction of a shunt would probably prove impossible.
