Year
2018
Abstract
Sandia National Laboratories (SNL) maintains an item type inventory of Special Nuclear Material (SNM) consisting of a wide variety of unique discrete items in different configurations, matrices and containers. The SNL Material Control and Accountability (MC&A) measurements program has developed an approach for confirmation measurement limit determination that includes a top down calculation of measurement error. These limits enable the detection of theft or substitution of SNM with relatively inexpensive equipment, a small staff and minimal impact to operations. Historical measurement data are used to create acceptance limits for items with similar attributes by leveraging the MC&A database of measurement records. A web-based calculator was developed by SNL Software Engineers and MC&A subject matter experts that mines the MC&A measurements data and performs dynamic, real time statistical limit calculations. By utilizing this database the SNL MC&A measurement team is able to calculate limits without the need for a statistically significant number of measurements on each discrete item. These limits are calculated from field measurements with similar geometries and instruments. As such the limit values include both systematic and random effects.