Migration of radionuclides

Thus, a proper backfill material may act as a very effective chemical and mechanical barrier, preventing free migration of radionuclides released from the waste containers. 

The effects of chemical interactions on the migration of radionuclides in the backfill material and in the ground can be described by the retention factor Kj, defined as ( )... 

Borg, I. Y., Stone, R., Levy, H. B., Ramspott, L. D., "Information Pertinent to the Migration of Radionuclides in Ground Water at the Nevada Test Site," Lawrence Livermore Laboratory, Rept. UCRL-52078, Part 1 "Review and Analysis of Existing Information," (May 25, 1976) ... 

A number of methods have been proposed for predicting the migration of radionuclides through the soil. Most methods have used a concept of layers of soil, one upon another, with the radionuclide migrating from the top layer downward. 

This proposal differs from the others discussed previously in that the first three waste classes all would include waste that is generally acceptable for disposal in a near-surface facility. However, these three classes differ in the extent to which engineered barriers would be relied upon to inhibit migration of radionuclides and exposures of inadvertent intruders. 

The groundwater transport of radionuclides through waterbearing interbed layers in the Columbia River basalt formation will be controlled by reactions of the radionuclides with groundwater and interbed solids. These interactions must be understood to predict possible migration of radionuclides from a proposed radioactive waste repository in basalt. Precipitation and sorption on interbed solids are the principle reactions that retard radionuclide movement in the interbeds. The objective of the work described herein was to determine the sorption and desorption behavior of radionuclides important to safety assessment of a high-level radioactive waste repository in Columbia River basalt. The effects of groundwater composition, redox potential, radionuclide concentration, and temperature on these reactions were determined. 

Role of Organics in the Subsurface Migration of Radionuclides in Groundwater... 

In addition to the above studies, radiochemical analyses were performed on water which flowed into the experimental trench during its construction. Initial radionuclide concentrations in the water were comparable to those in water from waste trench 27 (Table I), indicating that subsurface migration of radionuclides has occurred over short distances on site at Maxey Flats. When the experimental trench was resampled later, the radionuclide concentrations were much lower, perhaps because the trench design perturbed the migration of radionuclides. Consequently, we installed and sampled a series of inert atmosphere wells around the experimental trench. 

Besides, radioactive cobalt is a common radionuclide in liquid wastes from nuclear facilities, and natural erionite is a good exchanger for 60Co2+. Studies carried out with this material reveal its possibilities in the elimination of radioactive cobalt from solutions [73], The exchange of 232Th4+ in natural clinoptilolite and mordenite from liquid solutions has also been studied [74], All these peculiarities of natural zeolites make it suitable to be exploited as natural barriers for the migration of radionuclides and, consequently, natural zeolite deposits can be potential sites for a radioactive waste repository [19]. These materials have also been employed for the removal of radionuclides from polluted areas in places where nuclear power station accidents have occurred or where... 

Baetsle LH (1969) Migration of radionuclides in porous media. In Duhamel AMF (ed) Progress in nuclear energy series XII health physics. Pergamon Press, Elmsford, New York... 

There was studied the migration of radionuclides, first divided into three groups,... 

Erdal BR, Daniels WR, Hoffman DC, et al. 1979. Sorption and migration of radionuclides in geologic media. Mater Res Sci Basis Nucl Waste Manage 423-426. 

Besides the composition of the soils, other factors have a major influence on the migration of radionuclides rainfall, the thickness of the soil layers, their permeability to water, and the nature of the layers underneath. For example, Cs is washed down quickly through layers of sand, but it will stay in layers of clay. Pu is sorbed by clay more strongly than by sand and may stay in soils for rather long times, if it is not dissolved by complexation or displaced by other compounds. 

M. Loxham et al (1983), The influence of soil heterogeneity on the migration of radionuclides in the soil and soil water system. EEC contract 193-81-6-was-NL-Brussels. 

The value of Kd depends on the experimental conditions, but it is widely believed that a Kjj determined at certain experimental conditions can be used to predict sorption for given adsorbent-adsorbate combination. The variability of Ku was emphasized by Krupka et al. [30], who recently collected Kd values related to migration of radionuclides in geosphere. A dozen of less recent compilations of Ko was quoted by Jenne [31]. 

G. Buckau (Ed.). Effects of Humic Substances on the Migration of Radionuclides Complexation and Transport of Actinides. Report FZKA 6124. Forschungszentrum... 

Lester, D.H., Jansen, G., and Burkholder, H.C., Migration of Radionuclide Chains Through an Adsorbing Medium, BNWL-SA-5079, Battelle Pacific Northwest Laboratories, Richland, WA, December 1974. 

When radionuclides are stored as wastes either in permanent repositories or in waste storage areas the possibility of escape into the environment must be considered. This escape may result in airborne contamination or in contamination of environmental surfaces. This paper will not concern itself with airborne contamination but rather with the surface contamination and the transport and migration of radionuclides into the lithosphere through the agency of water. 

ScHiMMACK W, Bunzl K and Zelles L (1989) Initial rates of migration of radionuclides from the Chernobyl fallout in undisturbed soils. Geoderma 44 211-217. 

J.-C. PErrr, Migration of Radionuclides in the Geosphere What Can We Learn from Natural Analogues , in Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere, Radiochim. Acta, special issue 58/59 (1992). 

Higashi, K. Pigford, T. H. (1980) Analytical models for migration of radionuclides in geologic sorbing media. J. Nucl. Sci Technol. 17,700-709. 

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