Nuclear waste chemistry

Several research topics in the Chemistry Division are directly related to chemical problems of high-level radioactive waste disposal. Safety analyses of radioactive waste disposal depends upon reliable prediction of radionuclide migration in the event of penetration of the nuclear waste repository by groundwater and flow of the groundwater to the accessible environment. Prediction of the interaction of migrating nuclides with host geological formations is dependent upon knowledge of the speciation of the nuclides. Research is described concerning the effects of valence states of the nuclides on the sorption of these nuclides by minerals in the formations. In particular the sorption behavior of Tc(VII) and Np(V) is discussed. This type of information is used by the US Nuclear Regulatory Commission (NRC) for the assessment of the performance of proposed repository sites. In the other sections, other types of chemical support for assessment activities are described. For example evaluation of parameters for the migration of technetium and uranium in host-rock formations is given. 11 refs