Separation of cesium from acid ILW-Purex solutions by sorption on inorganic ion exchangers

The separation of cesium by use of the inorganic ion exchanger ammonium molybdatophosphate from nitric acid solutions of intermediate level waste (ILW) from reprocessing of spent fuel elements according to the PUREX PROCESS has been demonstrated. Other inorganic exchange materials have shown high sorption values only for certain pH ranges: ammonium hexacyano cobaltous ferrate (pH 12, 35 g Cs/kg), potassium hexacyano nickel ferrate (pH 10, 30 g Cs/kg), zirconium phosphate (pH 7, 100 g Cs/kg), titanium phosphate (pH 7, 15 g Cs/kg), antimony pentoxide (pH 2, 30 g Cs/kg) and titanium oxide (pH 7, 1 g Cs/kg). Except for high salt loading of 3.6 M NaNO3, a significant loss of capacities usually occurs; this does not allow the use of these exchangers. However, ammonium molybdatophosphate shows excellent performance with high salt loadings and in a broad pH-range from pH 9 to conc. HNO3 with a breakthrough-capacity of 60 g Cs/kg. (orig.)