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Analyses of mass transport in a nuclear waste repository in salt
Author(s) -
Hwang Y.,
Pigford T. H.,
Chambré P. L.,
Lee W. W.L.
Publication year - 1992
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/92wr00470
Subject(s) - brine , radioactive waste , radionuclide , consolidation (business) , nuclide , environmental science , mass transport , geology , chemistry , thermodynamics , nuclear chemistry , physics , nuclear physics , business , engineering physics , accounting
Salt is the proposed host rock for geologic repositories of nuclear waste in several nations because it is “dry” and probably “impermeable”. To evaluate the safety of nuclear waste disposal in salt, it is necessary to calculate the rate of release of nuclides from solidified waste form and to predict the transport of released radionuclides. Our objective is to develop analytic methods for such prediction, based on mass transfer theory. First, we present an analysis of pressure‐driven brine migration. After consolidation, brine migration analyzed by these equations and using the particular set of parameter values is of a small magnitude, with Darcy velocities of the order of micrometers per year. Brine migration in consolidated salt is very localized, within a few meters from the waste package, and highly transient. We have analyzed diffusion of radionuclides near waste packages in a salt repository, using analytic equations for low Peclet systems. According to this analysis it is unlikely that any low‐solubility species will have difficulty meeting the U.S. Nuclear Regulatory Commission release rate requirement at the bare waste/salt interface. We have also analyzed the role that an interbed might play in being a preferential pathway for radionuclide migration. We calculate the diffusive mass fluxes from an infinitely long bare waste cylinder in salt, facing an interbed. The fractional release rates of solubility‐limited species into the interbed are low for the parameter values used in the numerical illustrations.