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Impact of the number of material measurement categories on measurement error

Description: There is nearly always some mismatch between the physical properties of items containing nuclear material and standards used to calibrate the assay method. Physical properties include the density and heterogeneity of the item's nonnuclear material and the type of interfering species, such as hydrogen in the case of neutron counting. Some assay techniques are less sensitive to variation in physical properties than others and can be used to generate working standards. Provided that a reference assay method 1 (often calorimetry) is available that is well characterized (having negligible or known dependence on varying physical properties), we can assess the total measurement error of another method 2. In this paper we consider the impact of the number of measurement categories on the measurement error standard deviation of method 2. We assume that working standards (traceable to primary reference standards) are provided by the method 1 assay of actual facility items. Given the same number of working standards, we evaluate the tradeoff between using more working standards for each of a fewer number of categories versus using fewer standards in each of more categories. This leads to a method to determine a good allocation of working standards.
Date: January 1, 2002
Creator: Burr, Tom; Hemphill, G. M. (Geralyn M.); Longmire, V. L. (Victoria L.) & Smith, M. K. (Morag K.)
Partner: UNT Libraries Government Documents Department

Attribute measurement systems prototypes and equipment in the United States.

Description: Since the fall of 1997, the United States has been developing prototypical attribute verification technology for potential use by the International Atomic Energy Agency (IAEA) under the Trilateral Initiative. The first attribute measurement equipment demonstration took place in December 1997 at the Lawrence Livermore National Laboratory. This demonstration led to a series of joint Russian Federatioin/US/IAEA technical discussions that focused on attribute measurement technology that could be applied to plutonium bearing items having classified characteristics. A first prototype attribute verification system with an information barrier was demonstrated at a Trilateral Technical Workshop in June 1999 at Los Alamos. This prototype nourished further fruitful discussions between the three parties that has in turn led to the documents discussed in a previous paper. Prototype development has continued in the US, under other initiatives, using an integrated approach that includes the Trilatleral Initiative. Specifically for the Trilateral Initiative, US development has turned to some peripheral equipment that would support verifications by the IAEA. This equipment includes an authentication tool for measurement systems with information barriers and in situ probes that would facilitate inspections by reducing the need to move material out of storage locations for reverification. In this paper, we will first summarize the development of attribute verification measurement system technology in the US and then report on the status of the development of other equipment to support the Trilateral Initiative.
Date: January 1, 2001
Creator: Langner, D. C. (Diana C.); Landry, R. P. (Robert P.); Hsue, S.-T. (Sin-Tao); MacArthur, D. W. (Duncan W.); Mayo, D. R. (Douglas R.); Smith, M. K. (Morag K.) et al.
Partner: UNT Libraries Government Documents Department