Uranium adsorption and fixation processes at the Koongarra analogue site, Northern Australia

Abstract

In an international project extending over two decades, the Koongarra uranium deposit in Northern Australia has been studied as a model of radionuclide migration processes that are of relevance to assessing the safety of radioactive waste repositories. The research effort has included detailed studies of uranium adsorption on mineral surfaces, and of subsequent processes that may lead to the long-term immobilisation of uranium. Similar processes are expected to be of significance in assessing the long-term behaviour of radionuclides in the vicinity of a radioactive waste repository. Uranium adsorption has been experimentally studied, and modelled, on various samples, including complex natural materials from the Koongarra ore body as well as simple model minerals (such as clays or iron oxides). In addition, considerable effort has been expended to compare laboratory and in-field uranium distribution data. The Koongarra deposit is believed to be one of the few field sites where this type of comparison has been attempted. This paper reviews the research at Koongarra and in particular focuses on the value of the natural analogue site for integrating the results of a complex series of laboratory, modelling and field studies. © The Authors