Numerical simulation of the influence of humic-complexation on the migration of radionuclide through porous media; A Consideration of the sensitivity of analytical parameters

Tanaka, Tadao ; Mukai, Masayuki 

The present paper describes a theoretical evaluation of the influence of humic-complexation on migration of cationic radionuclides through porous media, where it is assumed that complexation reactions between radionuclides and natural organics, such as humic acid and fulvic acid, can be regarded to follow an instantaneous equilibrium or a first-order kinetic reaction. The calculation results revealed that radionuclide migration in the presence of humic substance was predominantly controlled by relative magnitude of distribution coefficients between the cationic radionuclides and the complexed radionuclides. Radionuclide migration was also affected significantly by the stability of the complexes or the rate constants of the complexation reaction.