Moderation of uncertainty in a database of sorption coefficients, 1; Factors drawing the scatter in database and data selection

Oe, Toshiaki*; Nagasaki, Shinya*; Kimura, Hideo; Takeda, Seiji ; Sekioka, Yasushi; Kato, Hiroyasu*

Sorption coefficients complied in a database have been checked for the sake of keeping the consistency. Major factors affecting the data scatter were examined by applying the mechanistic sorption models such as ion exchange and/or surface complexation models for the case of bentonite, clay minerals, and rock samples. The results suggested there were few data sets that were enough for the analysis by the later model. The sorption coefficients of neptunium or selenium on quartz and neptunium, tin and uranium on bentonite covers wide pH range and can be applicable for the extended analysis by the surface comlexation model. As for the case of cesium that is the key elements in performance analysis, the experimental condition such as ionic strength, mixture of sand are of great importance. Procedures were examined to speculate the parameters, which are not explicitly indicated in the data base and necessarily used in the ion exchange model, to reduce the variance of the sorption data.