Ion Exchange Automatic Elution System Used in the Full‐Scale Aqueous Scrap Purification of Plutonium‐238 Dioxide

The Aqueous Scrap Recovery process at Los Alamos is designed to produce pure Plutonium Oxide (238PuO2) from scrap or impure sources. The incoming 238PuO2 contains a significant amount of impurities that must be removed before it can be processed any further. One of the purification steps involves the ion exchange process. This process sorbs the putative [Pu(NO3)6]2− dianion onto an anion exchange resin (Reillex™ HPQ), while impurities are washed from the Pu sorbed resin. Most impurities in the solution do not sorb to the resin and are part of the effluent stream. During the wash cycle, 7 M of nitric acid is pumped through the resin column to wash the resin of unsorbed impurities. The solution collected (with impurities) is the wash stream. In some cases, an online gamma spectrophotometer is used to monitor the wash stream for 234U and 241Am, and ensures that a large percentage of these isotopes have washed through the column, indicating efficient separation from the plutonium. In the final step of the pro...