(GRS 169) Vergleich der Rechenprogramme LOPOS und MARNIE

The computer codes MARNIE and LOPOS are used to calculate the release of contaminants from the near field of a repository. Both programs mainly apply the same models for physical and chemical effects influencing the release and transport of contaminants.
They are different in the numerical algorithms to calculate release and transport. The programs have been developed by GRS for different applicants. In the present study the results of both codes are compared to analytical solutions for simplified geometrical structures of a repository. Furthermore, the results are compared with each other for test cases of more complex repository structures. In total, the agreement of the results is satisfying, especially in the cases of comparison with the analytical solutions. Some differences are explained by different geometrical modelling needs of the codes. Other small differences for vertically extended repositories are explained by different approaches for the depth dependency of convergence. In one test case larger differences occur. In this case a simplified analytical estimation favours the LOPOS results.