Year
2001
Abstract
Several information and data sources are required in order to evaluate inventory differences (IDs) of special nuclear material (SNM). The preferred method to evaluate IDs is to estimate the total measurement error standard deviation (sID) and “alarm” if an ID exceeds approximately 2 sID. The procedure for estimating sID is usually referred to as propagation of variance (POV), which involves estimating the standard deviation of many combined measurements. For example, the ID could consist of many input and output bulk (weight or volume) measurements, each of which is combined with a concentration of SNM measurement to arrive at a mass of SNM estimate. Several DOE sites have expressed interest in a more automated and more standardized approach to estimating sID. Therefore, DOE has funded Los Alamos National Laboratory to develop a tool to automate (and standardize when possible) POV. This paper will describe a Visual Basic tool that provides (1) a graphical description of the physical process; (2) links to information/data sources such as measurement control or remeasurement data, and (3) simplified POV equations to accommodate many, but not all POV applications.