par Smidts, Olivier
Référence Monte Carlo methods and applications, 4, 4, page (289-318)
Publication Publié, 1998-01
Article révisé par les pairs
Résumé : In the context of contaminant transport in geological media, the estimation of concentration (or activity) in local areas is addressed in this paper. Recently, a non-analog Monte Carlo simulation based on the integral formulation of the advectiondispersion equation in a saturated porous medium has been obtained. The present work describes, firstly, the random walks constructed from this integral equation for the transport of radionuclide chains, secondly, how these random walks may be easily modified in order to assess cumulative activities (integrated over the simulation time) in local areas of the geological medium. The method is based on the calculation of transition probabilities by simple quadratures during a pre-processing step. The simulation itself is organized as a random walk with multiple branchings. The estimation of instantaneous activities at points is also treated. The methods are illustrated on numerical tests in one and three-dimensional problems. © 1998 VSP.