Year
2012
Abstract
The goal of this work is to evaluate diversion scenarios that remove a significant quantity (8 kg) of Pu from the first Pu cycle of the PUREX process. These scenarios were chosen solely for the purposes of demonstrating the utility of process monitoring in the safeguards realm, and do not necessarily represent realistic or likely diversion paths. One simple scenario is to increase the increased input flow to the holding tank so that the input flow minus the diversion flow is equal to the expected output flow. The flow into the tank could be monitored using either a flow meter or a tank level meter. Based on the accuracy of commercial flow meters, this diversion would be hard to detect. On the other hand, if a tank level meter is employed, then such a diversion could be easily detected. A second diversion method would be to change the strip feed flow rate, and therefore the hydroxylamine nitrate (HAN)/Pu+4 ratio. This approach will not have a large impact on redirecting significant quantities of Pu out of the system with the U-loaded solvent, even if the strip flow rate is reduced by as much as 50%. Such a large change in flow rate would be easily detected with commercial flow meters. Therefore, the first Pu cycle of the PUREX process can be effectively safeguarded by monitoring the process in two ways, 1) the tank level for the loaded solvent exiting the extraction section and 2) the flow rate of the Pu strip feed.