(477d) Dechloriation of Electrorefiner Chloride Salt Via Ion-Exchange Using Ultra-Stable H-Y Zeolite

A dechlorination process has been designed to generate durable waste forms from spent nuclear fuel electrorefiner salt waste. It is based on ion exchange of the radioactive chloride salt with dehydrated protonated ultrastable Y-type (USHY) zeolite to form metal exchanged zeolite and gaseous HCl. This process has been demonstrated using both LiCl-KCl and surrogate electrorefiner salt in a small-scale rotary tube furnace. Dechlorination was confirmed and measured using both free chloride ion analysis of samples of the ion exchanged zeolite and output of an autotitrator that continuously balances HCl generated in real time. Preliminary results showed that over 90% dechlorination was achieved in 48 hr using pelletized USHY (Si/Al=2.6) at 625⁰C in a continuous rotary tube furnace without zeolite structure collapse. Temperatures of 650^oC or higher result in rapid collapse of the zeolite structure into an amorphous phase. The rate of the ion exchange is invariant when reducing particle size below 250 micron diameter, indicating that particle mixing is likely the rate limiting process. In addition to electrorefining waste processing, this technology could be used to generate waste forms from salts used in a chloride molten salt reactor (Cl-MSR).