Abstract and subjects
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 am further. One of the purification steps involves the ion exchange process. This process sorbs the putative [Pu(NO3)6] - 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 process, the Pu is released (desorbed) from the resin by pumping eluant through the column during the elution cycle. Typically, the eluant used to desorb the plutonium is 0.45 M HNO3. The focus of this presentation discusses an automated elution process that has been incorporated into the system used at Los Alamos in the event that the operators must vacate the laboratory in the case of an emergency. The automated elution process is triggered by temperature, pressure, and liquid level signals being monitored on both Ion Exchange columns. The automated system relies on the commercially available Lookout software to control each pump and valve in the system and is programmed to perform an automatic elution for a preset time if any of the operational limiting conditions are met.