Radionuclide Transport in a Dolomite Aquifer

The most probable paths for radionuclide transport between the biosphere and the proposed bedded salt repository (WIPP) in southeastern New Mexico are through dolomite formations which are the only currently water-bearing units overlying the repository horizon. This paper describes some of the experimental work performed to determine the potential for radionuclide migration in these formations. Included are the results of radionuclide sorption studies on natural dolomites (Magenta and Culebra) and on synthetic dolomite (proto-dolomite). Sorption on natural dolomites was evaluated with respect to core sample location, ground water composition, nuclide concentration and water volume to rock mass ratios used in making the measurements. The results show that a discrete value such as a distribution coefficient (Kd) assigned to a given radionuclide does not accurately describe its interactions with site specific geological formation.