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RECORD NUMBER: 4 OF 13

OLS Field Name OLS Field Data
Main Title Exact Solution for the Assessment of Nonequilibrium Sorption of Radionuclides in the Vadose Zone.
Author Drake, R. L. ; Chen, J. S. ; Jewett, D. G. ;
CORP Author National Risk Management Research Lab., Ada, OK. ;Dynamac Corp., Ada, OK.
Publisher Feb 2002
Year Published 2002
Stock Number PB2003-102102
Additional Subjects Radionuclides ; Radioactive waste disposal ; Radionuclide migration ; Underground disposal ; Assessments ; Impacts ; Vadose zones ; Nonequilibrium sorption ; HYDRUS Code
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NTIS  PB2003-102102 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 07/23/2003
Collation 28p
Abstract
In a report on model evaluation, the authors ran the HYDRUS Code, among other transport codes, to evaluate the impacts of nonequilibrium sorption sites on the time-evolution of (sup 99)Tc and (sup 90)Sr through the vadose zone. Since the authors' evaluation was based on a rather low, annual recharge rate, many of the numerical results derived from HYDRUS indicated that the nonequilibrium sorption sites, in essence, acted as equilibrium sorption sites. To help explain these results, the authors considered a 'stripped-down' version of the HYDRUS system. This 'stripped-down' version possesses two dependent variables, one for the radionuclides in solution and the other for the radionuclides adsorbed to the nonequilibrium sites; and it possesses constant physical parameters. The resultant governing equation for the radionuclides in solution is a linear, advection-dispersion-reaction (i.e., radioactive decay) partial differential equation containing a history integral term accounting for the nonequalibrium sorption sites. It is this 'stripped-down' version, which is the subject of this paper.