Salt‐Occluded Zeolites as an Immobilization Matrix for Chloride Waste Salt

The pyrometallurgical processing of spent fuel from the integral fast reactor (IFR), an advanced reactor under development at Argonne National Laboratory, will generate a chloride salt waste containing the alkali‐metal, alkaline‐earth, and some of the rare‐earth fission products. Salt‐occluded zeolite A, formed by equilibrating simulated molten waste salt and zeolite A, has been investigated as an immobilization matrix for this salt waste. In this concept, the chloride waste salt is loaded into the zeolite cavities, and cesium and strontium from the salt are preferentially sorbed by the zeolite. Experiments showed that the salt‐occluded zeolite powders are leach resistant and radiation stable. The conclusion is that the salt‐occluded zeolite is a promising immobilization matrix for the IFR waste salt.