PNNL

Abstract

The IAEA has established international safeguards standards for fissionable materials at spent fuel reprocessing plants to ensure that significant quantities of weapons-grade nuclear material are not diverted over a specified time frame. It is, therefore, necessary to confirm proper operational performance to verify facilities operate under adequate safeguard-declared conditions. This verification can be achieved by employing monitoring equipment. Online real time monitoring of the flowsheet radiochemical streams provides a unique capability to rapidly identify deviations from normal operating conditions. Flowsheet monitoring technologies being developed at PNNL include three integrated systems: Multi-Isotope Process (MIP) Monitor, spectroscopy-based monitor (UV-vis-NIR and Raman spectrometers), and Electrochemically Modulated Separations (EMS). The MIP Monitor is designed to identify off-normal conditions in process streams using gamma spectroscopy and pattern recognition software. The spectroscopic monitoring continuously measures chemical compositions of the process streams including actinide metal ions (U, Pu, Np), selected fission products, and major cold flowsheet chemicals. EMS provides an on-line means for pre-separating and pre-concentrating elements of interest out of complex matrices prior to detection. PNNL is preparing to test these multi-parametric technologies using different samples of dissolved spent fuel and aqueous and organic phases of the PUREX and UREX flowsheets. We will report our on-going efforts with specific focus given to quantifying sensitivity of the MIP Monitor and UV-Vis and Raman spectrometers to detect minor changes in major process variables.