Radionuclide transport in a multiple and parallel fractured system

Abstract

This paper is to study the effects of fracture width on the transport of a radionuclide in a multiple and parallel fractured rock formation. The equation describing the transport of the radionuclide released from the geological repository includes the following mechanisms: advection, dispersion, radioactive decay, and adsorption on the fracture surfaces. The concentration at the inlet of each fracture is assumed constant. An analytical solution was derived based on such a mathematical model by the Laplace transform technique. The solution indicates that identical concentration distributions can be observed in each fracture of the equal-width parallel fractured system. In an unequal-width fractured system, the penetration distances along wide fractures are generally larger than that in a single uniform fractured system. The radionuclide concentration in the wide fracture quickly reaches source concentration in the near-field environment, confirming that the fracture width plays an important role in radionuclide transport through a system of multiple and parallel fractured media.