| Autor: |
Smith, L. Eric, Jordan, David V., Misner, Alex C., Mace, Emily, Orton, Chris |
| Předmět: |
|
| Zdroj: |
Proceedings of the Institute of Nuclear Materials Management Annual Meeting; 2010, p1-11, 11p, 2 Color Photographs, 1 Diagram, 1 Chart, 5 Graphs |
| Abstrakt: |
Pacific Northwest National Laboratory (PNNL) is developing the concept of an automated UF6 cylinder verification station that would be located at key measurement points to positively identify each cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until arrival of IAEA inspectors. At the center of this unattended system is a hybrid enrichment assay technique that combines the traditional enrichment-meter method (based on the 186-keV peak from U-235) with non-traditional neutron-induced high-energy gamma-ray signatures (spawned primarily by U-234 alpha emissions and F-19(α,n) reactions). Previous work by PNNL provided proof-of-principle for the non-traditional signatures to support accurate, full-volume interrogation of the cylinder enrichment, thereby reducing the systematic uncertainties in enrichment assay due to UF6 heterogeneity and providing greater sensitivity to material substitution scenarios [Smith_1][Smith_2]. The work described here builds on that preliminary evaluation of the non-traditional signatures, but focuses on a prototype field system utilizing NaI(Tl) and LaBr3(Ce) spectrometers, and enrichment analysis algorithms that integrate the traditional and non-traditional signatures. Results for the assay of Type 30B cylinders ranging from 0.2 to 4.95 wt% U-235, are described for the following enrichment analysis methods: 1) Traditional enrichment meter signature (186-keV peak) as calculated using a square-wave convolute algorithm; 2) Non-traditional high-energy gamma-ray signature that provides neutron detection without neutron detectors and 3) Hybrid algorithm that merges the traditional and non-traditional signatures. Uncertainties for each method, relative to the declared enrichment for each cylinder, are compared to the IAEA's uncertainty target values for feed, tail and product cylinders. The prospects (e.g. assay accuracy and operational advantages) for the application of this new hybrid assay method in an automated cylinder verification station at a modern gaseous centrifuge enrichment plant are discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
