Jesús Carrera Ramírez

Radionuclide migration: coupling transport and chemistry

Abstract: This chapter contains a description of the formulation and applications of reactive transport (RT). Transport is especially relevant for fast reactions, whose rate is controlled by mixing. Therefore, emphasis is placed on mixing driven RT, which requires revising the traditional transport equation (advection–dispersion equation). The mechanics of RT is illustrated through simple cases (single species kinetics, binary reactions). This yields insights into the phenomenon and sets the frame for general RT, whose numerical aspects are also discussed. The chapter concludes with four application examples: (1) dissolution at a fresh-salt water interface (mixing controlled RT); (2) remediation of a 137Cs contaminated soil (cation exchange); (3) RT through fractured media (mixing enhancement by fractures); and (4) uranium migration (complex multicomponent RT).