Year
2017
Abstract
Current safeguards practices of verifying nuclear material (NM) at reprocessing facilities utilize Flow Key Measurement Points (FKMPs) to maintain continuity-of-knowledge (CoK) by monitoring the transfer of solutions between Material Balance Areas (MBAs). To do this, a Solution Monitoring and Measurement System (SMMS) is installed at each boundary tank to measure the solution density and volume that are then compared to determine differences and possible diversion. Since SMMSs are installed only at the MBA boundary tanks, the actual transfer in the pipes is not monitored directly. As such, potential misuse of the facility has a higher probability to be undetected in a timely manner, especially for unverified solutions. To offset this safeguards verification limitation, we propose measuring gamma rays from solutions passing through the pipes between MBAs. This has the potential to provide both real-time flow measurements and Pu isotopic composition quantification (of purified-solution batches) through passive non-destructive assay of the NM between FKMPs. This concept was tested by recent experimental studies performed at the Japan Atomic Energy Agency’s Plutonium Conversion Development Facility of gamma rays observed during Pu-nitrate flowing in pipes. To provide comprehensive CoK, the gamma-ray spectrum of the in-pipe solution could then be compared to similar spectra collected at the FKMPs, with the entire gamma-ray monitoring system able to be run in an unattended mode. This presentation will describe the concept details and analysis of using gamma ray pipe monitoring as a capability for real-time safeguards verification.