R. Metcalf, A. Bevill, W. Charlton, R. Bean, “Safeguards Envelope: Previous Work and Examples”, 49th Annual INMM Meeting, Nashville, TN, July 13-17, 2008.
The future expansion of nuclear power will require not just electricity production but fuel cycle facilities such as fuel fabrication and reprocessing plants. As large reprocessing facilities are built around the world, they must be built and operated in a manner to minimize the risk of nuclear proliferation. Process monitoring has returned to the spotlight as an added measure that can increase confidence in the safeguards of special nuclear material (SNM). Process monitoring can be demonstrated by Markov Monte Carlo simulations to lengthen the allowable inventory period by reducing accountancy requirements, and to reduce false positive indications. The next logical step is the creation of a Safeguards Envelope, a set of operational parameters and models to maximize anomaly detection and inventory period by process monitoring while minimizing operator impact and false positive rates. A brief example of a rudimentary Safeguards Envelope is presented, and shown to detect synthetic diversions overlaying a measured processing plant data set. This demonstration Safeguards Envelope is shown to increase the confidence that no SNM has been diverted with minimal operator impact, even though it is based on an information sparse environment. While the foundation on which a full Safeguards Envelope can be built has been presented in historical demonstrations of process monitoring, several requirements remain yet unfulfilled, such as reprocessing plant transient models, inclusion of operating data with indirect correlation to SNM movement, and exploration of new methods of identifying subtle events in transient processes.