Year
2015
Abstract
The pyrochemical method of reprocessing partitions fissile material intended for recovery from high-level waste, thereby reducing the final waste volume. However, this process involves unique operating requirements, including high operating temperatures in an inert atmosphere, thereby limiting the applicability of current accoun- tancy techniques for aqueous reprocessing methods. While pyroprocessing is currently in the engineering-scale phase of development and no complete material accountancy process has been developed for this flowsheet, sev- eral methods show promise as accountancy measurement techniques, such as cyclic voltammetry, laser-induced breakdown spectroscopy (LIBS), and hybrid K-edge densitometry (HKED). Integration of cyclic voltammetry and LIBS into a safeguards regime poses several challenges such as characterizing multiple component systems and only measuring the surface of a sample. By contrast, HKED shows great promise as an accountancy measurement technique due to its ability to rapidly and non-destructively determine elemental compositions of complex chemical solutions throughout the entire sample without penetrating the process atmospheric barrier. Direct physical modification of a HKED system to determine its applicability to pyroprocessing safeguards would normally be cost-prohibitive; therefore, in order to investigate the feasibility of applying HKED to pyropro- cessing safeguards, a computational model of a commercial HKED system was developed and validated against sample measurements made at Oak Ridge National Laboratory. Several samples of interest from a pyroprocessing operation were simulated including a variety of complex sample media characteristic of materials in various stages of a pyroprocessing flowsheet, including evaluating the feasibility of measurements of minor actinide con- centrations (i.e., Np, Am, and Cm). These scoping studies will provide the capability to efficiently and effectively develop the safeguards regime for pyroprocessing.