In this work the comparison between two numerical codes proposed for use in the compliance assessments, notably HYDRUS and PORFLOW, for calculation of water flow and transport phenomena is addressed. The focus of this work is two-fold. On one hand the verification of codes is shown through the comparison between HYDRUS and PORFLOW codes in different dimensions and on the other hand the effect of model dimensionality is analyzed for each simulation code. The first simplification applied to the numerical model usually is in the reduction of dimensionality. But with the simplification of the model some important factors might be omitted. For the purpose of evaluating the reduction in model dimension on radionuclide release, a numerical model which is an abstraction of one monolith containing 4 waste drums was established. The results are expressed in terms of radionuclide fluxes at the bottom of the monolith. Result show that the reduction of dimensionality for the imposed water fluxes and radionuclides used gives only small differences, and that the 1D models proposed for use in compliance assessment are sufficiently accurate. Results further showed the large sensitivity of calculated fluxes to the choice of solute transport boundary conditions.
|Number of pages
|Published - May 2007
|Studiecentrum voor Kernenergie