Radionuclide underground migration

This computational model calculates the annual radiological dose to humans over geological time scales due to the underground migration of radionuclides from a hypothetical nuclear waste disposal site through a system of idealised natural and engineered barriers. 

To assess the release by this scenario, it is necessary to evaluate the rate of release from the package, the flow rate of the underground fluids, the speciation and solubility of the differrat radionuclides and their diffusion (migration) rates. 

One namral analogue for geological disposal of nuclear waste is at a site near Oklo, Gabon, West Africa. About 2 billion yr ago, a uranium ore body sustained fission for a period of about 100,000 yr. Most of the fission and activation products from this namral reactor migrated only a short distance from the fission sites, which gives natural supporting evidence for the potential of radionuclide transport from underground waste disposal facilities. 

Evaluation of long-term safety assessments based on model predictions is difficult. While it is possible to evaluate the accuracy of a model by comparing the results with experiments on radionuclide migration behavior in underground facilities, such underground experiments are typically short-term (up to several years) investigations. 

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