U. S. Department of Energy Development of Unattended Process Monitoring Systems for Uranyl Nitrate Solutions

Year
2005
Author(s)
James Lemley - Brookhaven National Laboratory
Mark M. Pickrell - Los Alamos National Laboratory
Jennifer L. Ladd-Lively - Oak Ridge National Laboratory
John M. Begovich - Oak Ridge National Laboratory
H. Lambert - Lawrence Livermore National Laboratory
W. J. O'Connell - Lawrence Livermore National Laboratory
Diana Langner - Los Alarnos National Laboratory
Jae Jo - Brookhaven National Laboratory
Michael Whitaker - Oak Ridge National Laboratory
B. D. Boyer - Brookhaven National Laboratory
Michael C Miller - Los Alamos National Laboratory
Wesley Bicha - Oak Ridge National Laboratory
Lisa Loden - Oak Ridge National Laboratory
Hatam Elayat - Lawrence Livermore National Laboratory
Abstract
Current International Atomic Energy Agency (IAEA) policy considers any purified aqueous uranium solution or any purified uranium oxides to be nuclear material of a composition and purity suitable for isotopic enrichment or fuel fabrication, respectively. The U.S. Department of Energy (DOE) is developing instruments, tools, strategies, and methods that could be of use to the IAEA in the application of safeguards for materials found in the front end of the nuclear fuel cycle prior to the production of uranium hexafluoride or oxides that have been the traditional starting points of IAEA safeguards. One such material is purified uranyl nitrate solution produced in plants that convert ore concentrates to uranium hexafluoride via aqueous processes. Through its laboratories DOE is developing a system for unattended monitoring of the uranium content of purified uranyl nitrate solution produced in a natural uranium conversion plant (NUCP). The process monitoring system has three essential elements: a flow meter that measures the solution volume or mass flow; a neutron-based system to measure the uranium concentration of the solution; and a surveillance system that would detect tampering, attempts to bypass the monitoring system, or activities that might indicate undeclared production. The time-integrated product of incremental volume or mass flows and the concentrations gives the uranium content of the purified process material produced in the NUCP and can be compared with the uranium content of the declared plant products, e.g., uranium hexafluoride, oxide and/or metal. The monitoring system has been assembled and is being tested with uranium-containing solutions at ORNL. Further testing is planned to evaluate performance under processing conditions in an operating fuel-cycle facility. Progress in this multi-laboratory program, including the ongoing testing program, the concept for integration of unattended process-monitoring instrumentation at a NUCP operating under IAEA safeguards, and systems modeling concept, will be presented.