SIMFUEL dissolution studies in granitic groundwater

The dissolution behaviour of an unirradiated chemical analogue of spent nuclear fuel, SIMFUEL, has been studied in synthetic, granitic groundwater under anoxic conditions. The release of U and the minor components Mo, Ru, Sr, Ba, La, Zr, Ce, Y, Rh, Pd and Nd was monitored during static (batch) leaching experiments. For molybdenum, ruthenium, strontium and barium, the leaching results (the total experimental time of 300 days) show a trend to congruent dissolution with the UO2 matrix. The release rates of lanthanum, zirconium and cerium are higher relative to uranium. Sorption, colloidal and/or precipitation phenomena appear to play an important role under these experimental conditions.