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The Safeguards Envelope Methodology

A safeguards envelope is a set of operational and safeguards parameters that increases the confidence as to the location and assay of nuclear material. Facilities operating under safeguards envelopes operate under a higher confidence and lower false alarm rate with minimal operator impact. A full safeguards envelope gives a set of plant operator requirements that assures that the equipment and methods used to detect nuclear theft are at peak efficiency without having a significant impact on the efficiency of the nuclear facility.

Traditional safeguards techniques take into account a wealth of information, including containment and surveillance feeds, material flow rates, and exit monitoring. Additional operational information, such as pressure, temperature, reagent flow rates, process monitors, and other "non-safeguards" indicators typically available at the plants are used as elements in the creation of an advanced safeguards envelope.

These data feeds are combined with advanced mathematical anomaly detection models, neural network learning, or Bayesian probability theory to allow for the prioritization of resources to the most credible nuclear material theft situations. This prioritization will increase the likelihood of detecting a diversion, with the overarching safeguards operating envelope increasing the "safeguardability" of the facility by decreasing the time and cost of nuclear material accountancy.

Current research involves evaluation of the Idaho Chemical Processing Plant process monitoring data (including multi-monitor correlations), scalability studies, and operational impact studies.


  1. R. Metcalf, A. Bevill, W. Charlton, and R. Bean, "Safeguards Envelope: Previous Work and Examples," Proceedings of 49th Annual INMM Meeting, Nashville, TN, July 13-17, 2008. See Document
  2. R. Metcalf, J. Ragusa, and R. Bean , "Safeguards Envelope: The First Steps," Proceedings of 8th International Conference on Facility Operations - Safeguards Interface, Portland, OR, March 30 - April 4, 2008. See Document


Plot showing the envelope operation
Plot showing the envelope operation

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