Year
2011
Abstract
The non-destructive assay of uranium bearing materials to determine uranium enrichment is one of the most common measurements in nuclear safeguards applications, waste management, and fuel cycle process control. In the current climate of increased concern for the possible illicit diversion of these materials, a greater emphasis is being placed on verification measurements of enriched uranium. The enrichment measurements play an important role in establishing and verifying inventories of uranium. If greater accessibility is made for international inspections of increasingly bigger volumes of uranium bearing materials, then improved analysis methods that are quick and reliable will be essential for the safeguards community. The Multi-Group Analysis code for Uranium (MGAU) is a highly regarded and widely used computer code for the determination of the relative abundances of the uranium isotopes. It is used for a diversity of items with minimal prior information. MGAU is applied to the analysis of high resolution gamma ray spectra. Normal gamma spectroscopy analysis requires a spectrum to be energy- and efficiency-calibrated before analysis, and sequentially calls several analysis “engines” to perform the analysis. MGAU only requires an approximate spectrum energy calibration, and it performs its entire analysis in one step. The new version of MGAU (v4.2) includes multiple enhancements and incorporates feedback received from users using previous versions of MGAU. In this paper we outline the main changes to the code and describe why these improvements were conceived and implemented. These changes include enhancements in the analysis algorithms as well as in the user interface. A large set of uranium spectra of various items, covering a wide range of enrichments (0.3 to 97%) was used to test the new code and to compare analysis results to those obtained using the previous versions of MGAU. The results of these comparison data are also presented in this paper.