Elsevier

Chemical Geology

Volume 55, Issues 3–4, 25 June 1986, Pages 255-268
Chemical Geology

Natural analogues to the conditions around a final repository for high-level radioactive waste
Radionuclide migration around uranium ore bodies in the Alligator Rivers Region of the Northern Territory of Australia — Analogue of radioactive waste repositories — A review

https://doi.org/10.1016/0009-2541(86)90028-8Get rights and content

Abstract

A number of U ore bodies in the Northern Territory of Australia have been evaluated as geochemical analogues of high-level radioactive waste repositories. A mathematical model of the redistribution of U within the upper sequences of the ore body has been developed to rationalise observed U-series fractionation in terms of differential leaching rates, the rate of advance of the weathering front and assumed boundary conditions. Evidence is presented that the maximum uranium retardation factor down-gradient of the Ranger deposit is 1250. Groundwater colloids were found to carry between 0.01% and 2% 238U, and between 0.3% and 39% 230Th. In associated investigations of the weathered ore, it was found that between 50% and 98% 238U and between 74% and 97% 230Th is associated with the Fe minerals (predominantly ferrihydrite and goethite). Substantial 234U238U and 230Th234U fractionation attributed to α-recoil is observed. The possibility of incorporating chosen transuranic elements and fission products into the analogue is discussed.

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