Estimation of distribution coefficients of radioactive nuclides by analysis of background stable nuclides

It is necessary to measure the distribution coefficients of the critical nuclides, e.g. 90Sr, 60Co, 129I, etc. at the disposal site in relation to the safety assessment of the underground disposal. The measurement of the distribution coefficients has been so far conducted by batch experiments, column experiments, or field tracer experiments. In this report, a new method of estimating distribution coefficients of radioacive nuclides from the behavior of coexisting stable nuclides is proposed, and examined. The obtained results were as follows: (1) It was proved that the distribution coefficients of stable Sr agreed well with those of the fallout 90Sr at the same site. (2) The above findings strongly indicate that the method is appropriate for the purpose of the estimation. (3) Because of its simplicity and reliability, the proposed method is promising if much verified data are available. (author)