%A"Prij, J" %D1991 %I; Netherlands Energy Research Foundation (ECN), Petten (Netherlands) %2 %J[] %K12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES, RADIOACTIVE WASTE DISPOSAL, CONVERGENCE, SALT CAVERNS, COMPUTERIZED SIMULATION, 052002, WASTE DISPOSAL AND STORAGE %PMedium: X; Size: 8 p. %TAn improved model for the convergence of an excavation on rock salt. Paper to be presented at the International conference on structural mechanics in reactor technology (paper L19/5), Tokyo, Japan, August 18-23, 1991 %XDisposal of radioactive waste in salt formations requires exca-vations to be made in these geological formations. When time goes by the volume of these excavations will gradually decrease. This time dependent volume change is called the convergence of the excavation and is a result of both rock salt pressure and time dependent material behaviour and consequently depends strongly on depth and temperature. Convergence is an important process through which, with the lapse of time, any leakage of ground water into the repository can be excluded. On the other hand the same convergence ensures the contaminated brine to be extruded from a mine once flooded. An accurate safety analysis therefore requires an accurate model of convergence. In the computer code ENOS, used for the nuclide transport analyses, a special model for the convergence has been incorporated, based on experiments performed in the Asse. This model is based on a reference convergence rate K{sub ref} and includes multiplication factors to account for the effect of brine pressure in the borehole, changes in rock temperature and resistance of this backfill. K{sub ref} is the free volumetric convergence rate of an open borehole at reference rock pressure and temperature and is assumed to be constant. In this paper it is shown that the free convergence is not a constant. An improved convergence model is proposed which accounts for a transient free convergence. The accuracy of this model is tested with finite element analysis. (author). 6 refs.; 2 figs. %0Conference %NECN-RX-91-017; CONF-910817-;Other: ON: DE92613952; TRN: NL91C0835012505 %1 %CNetherlands %Rhttps://doi.org/ Other: ON: DE92613952; TRN: NL91C0835012505 NLN %GEnglish