Transport van radio-isotopen in de bodem

A survey is given of the different items in connection with radionuclide migration studied at the Belgian Nucleaer Centre at Mol. The methods used for measuring ground water velocities in the Mol sand quifer are reviewed. The detection devices based on sampling and chemisorption are shortly described and compared to the more universal "multicounter" method which may be used at whatever depth in unconsolidated sandy formations. The basic formulas used for the calculation of hydrodynamic dispersion are discussed with special emphasis on their application in accidental releases of radioactive contaminants in ground-water. The mathematics are given for the calculation of the size of a migrating cloud and the zone of influence from a continuous activity release. Finally, the new concept of chemical barrier is shortly described and illustrated by the possibilities of stopping migrating 90Sr ions in sandy layers treated with HF and K2H2Sb2O7.