An analysis of plutonium accountability in the COPRECAL process

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Virginia Polytechnic Institute and State University

In the late 1970's, emphasis on non-proliferation forced suspension of all commercial spent-fuel reprocessing. The spent-fuel storage problem plaguing the nuclear industry can be alleviated by reprocessing. For commercial spentfuel reprocessing to again become a reality, a process is needed to reform reprocessing operations such that non-proliferation goals are satisfied. To satisfy these goals, the existing process which generates plutonium-nitrate solution must be altered to generate plutonium-uranium oxide powder. The COPRECAL process is designed to produce this solid. The COPRECAL process allows uranium and plutonium to be extracted from spent-fuel for reuse in commercial lightwater reactors. The COPRECAL process is unique in that no pure plutonium is ever present throughout the process, whether the COPRECAL process is intrinsically vulnerable to plutonium diversion is the object of this work.

A simulation model of the COPRECAL process is presented which employs state-of-the-art instrumentation to measure in-process plutonium through the simulated passage of time. Plutonium diversion schemes are incorporated into the model. After simulated thefts, model output statistics are plotted on control charts and analyzed. Results show need for major design changes in the COPRECAL process.