Translation and development of the BNWL-geosphere model

The report deals with the rate of radioactivity discharge from a repository for radioactive waste in a geologic formation to the biosphere. A BASIC language computer program called GETOUT has been developed in USA. It was obtained by the Swedish project Nuclear Fuel Safety and has thereafter been translated into FORTRAN. The main extension of the code, that was made during the translation, is a model for averaging the hydrodynamic and geochemical parameters for the case of non-uniform packing of the column (e.g. considering a repository in cracked rock with crack width, crack spacing etc. in different zones). The program has been outtested on an IBM model 360/75 computer. The migration is governed by three parameters i.e. the ground water velocity, the dispersion coefficient and the nuclide retentivities. (L.B.)