| Autor: |
Sumi, Mika, Abe, Katsuo, Kageyama, Tomio, Nakazawa, Hiroaki, Kurosawa, Akira, Yamamoto, Masahiko, Mason, Peter, Neuhoff, Jon, Doubek, Norbert, Balsley, Steven, Verbruggen, Andre, Richter, Stephan, Jakopi, Rozle, Zuleger, Evelyn, van-Belle, Piet |
| Předmět: |
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| Zdroj: |
Proceedings of the Institute of Nuclear Materials Management Annual Meeting; 2010, p1-9, 9p, 1 Color Photograph, 1 Diagram, 5 Graphs |
| Abstrakt: |
Large Size Dried (LSD) spikes are currently used in many facilities in Japan (and around the world) for uranium and plutonium accountancy analysis by Isotope Dilution Mass Spectrometry (IDMS). The size and composition of the original LSD spike was based on the spike developed for earlier reprocessing facilities, and optimized for use at the Tokai Reprocessing Plant in the early 1990s. The LSD's contain nominally 2 mg Pu at >90% 239Pu abundance and 40 mg of uranium at about 20% 235U. Because of the large quantity of plutonium needed to support Japanese facilities and expected difficulties in the long term supply and transport of low burn-up Pu reference materials, JAEA decided to evaluate the possibility of using domestically available MOX as a source of Pu material for LSD spike preparation. At JAEA's Plutonium Fuel Development Center (PFDC), the plutonium contained in a sample of MOX was separated from the uranium and purified. The resulting Pu nitrate solution was characterized for its Pu content by controlled potential coulometry (CPC) and its isotopic composition by thermal ionization mass spectrometry. In collaboration with the New Brunswick Laboratory, the characterization measurements were evaluated using the "Guide to the Expression of Uncertainty in Measurements (GUM, JCGM 2008:100) to calculate the expanded uncertainties for the plutonium content and isotopics as well as the residual uranium content and isotopics. In addition to preparing and characterizing the plutonium source material, JAEA studied the use of two types of LSD spikes prepared from the Pu solution: "traditional" 2 mg Pu/40 mg U spikes and smaller LSD spikes containing 1 mg Pu and 0.5 mg HEU. The purpose of testing the smaller spike was to see if reduced Pu content would work, and also to optimize spike composition for the analysis of 1:1 MOX samples, for which the traditional LSD spike is not suitable. A supply of both sizes of spikes was produced and samples of each spike were distributed for verification measurements to the IAEA's Safeguards Analytical Laboratory, the Institute for Reference Materials and Measurement (IRMM), the Institute for Transuranium Elements (ITU), and several Japanese laboratories. The laboratories reported their results, in some cases including GUM-evaluated uncertainties, and the reported results were compared to the make-up value and evaluated by NBL and JAEA under their agreement. In addition to verifying the make-up value of the LSD spikes, JAEA studied the stability of the spikes over time and during transport. The stability of the smaller size spike was of most concern because of the low quantity of U. There were concerns that the small amount of U would allow flaking of the dried material leading to concerns that quantitative dissolution at the user site would be difficult if material were loose in the vial. Observations from shelf life and transport condition tests confirm that the small spikes remain stable more than one year after preparation and after undergoing international transport. Details of the Pu make-up value evaluation, the LSD spike preparation and the evaluation of the verification results will be presented. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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