CALCULATION OF THE RADIATION TRANSPORT IN ROCK-SALT USING MONTE-CARLOMETHODS

To improve the final concept for a high-level radioactive waste (HAW) disposal in geological salt formations, plans have been developed in G ermany for a full scale testing of an underground repository. As a mai n part of this so-called HAW project, the testwise emplacement of 30 v itrified highly radioactive canisters was planned in test galleries at the 800 m level of the Asse salt mine near Braunschweig, Germany. An attempt should be made to correlate the changes induced to the salt wi th the amount of energy deposited there. This paper provides absorbed dose rate and photon fluence rate distributions in rock salt around th ese highly radioactive canisters, containing the radionuclides Cs-137 and Sr-90, and around a single canister containing radioactive materia l of a lower activity level (INHAW experiment). The data given were ca lculated using a Monte Carlo method simulating photon transport in com plex geometries of differently composed materials. The aim of these ca lculations was to enable determination of the dose absorbed in any arb itrary sample of salt 1 m around the canisters to be further examined in the future with sufficient reliability for safety considerations. T he geometry of the test arrangement, the materials involved, the calcu lational method and selected results are shown.