Year
2006
Abstract
Renewed interest in nuclear energy has convinced the United States to reconsider fuel reprocessing. However, a need for increased national security has raised concerns about the adequacy of current materials accounting procedures in tracking uranium, plutonium, and other such materials. Many reprocessing facilities use conventional accounting systems that react slowly to material diversion. They also involve plant shutdowns, which are very costly. Nearreal- time accounting (NRTA) can provide a cheaper and more convenient alternative for both operators and inspectors. NRTA uses on-line measurements to test for material balance closure while the process is running. Statistical analysis on these material balances can alert the operator to missing material and other fault conditions. This paper describes modeling efforts used to test and improve NRTA systems. The model described is based on UREX+ reprocessing. Simulink, which is part of MATLAB, provides a user-friendly modeling environment. This model simulates process operations, and allows the user to simulate measurements of various flow streams and holdups. Simulations performed with this model will provide important information for evaluating instrumentation, forming sampling strategies, and reducing overall accounting costs. This paper details the modeling and explains the utility of such a model in improving nuclear safeguards. This work parallels the work of another paper being submitted, which will focus on instrumentation and sampling strategies.