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Okano, Masanori; Kuno, Takehiko; Charlton, W. S.*; Wells, C. A.*; Hemberger, P. H.*
46th Annual Meeting of the INMM, Final Program, Abstract 352, 0 Pages, 2005/07
According to achieve the International Atomic Energy Agency's safeguards criteria, development of simple and rapid determination method of Pu amount in the spent fuel has been required. It is known that stable xenon isotopes produced with fission reflect spent fuel characteristics (fuel type, burn up, Pu amount). Since dissolver off-gas which is released with dissolution of spent fuel in reprocessing facility, contains most of gaseous fission products, xenon isotopic ratio in dissolver off-gas sampled from the stack would be expected to provide a new measurement method for application to safeguards inspection. We have studied a new technique to evaluate Pu isotopic ratio and its amount in the fuel from Xe isotopic ratio, which is related to burn up. The technique is also applicable for evaluating burn up credit to achieve efficient critical safety control. Six batches of off gas from dissolution process, DOG: Dissolver off gas, were obtained with press pump from the stack in Tokai Reprocessing Plant at BWR fuel (approx. 30GWD/MTU) reprocessing campaign. Xe isotopic ratio was determined with Gas Chromatography- Quadrupole Mass Spectrometer, GC-QMS. Xe concentrations in the DOGs sampled at the stack were 1,000 to 10,000 ppm, which were enough concentrations for determining minor Xe isotopes. We evaluate burn up and Pu amount with NOVA, Noble Gas Environmental Monitoring Application code, developed by Los Alamos National Laboratory. Inferred burn up was realized 94% of confidences level, which is the conventional definition based on the standard deviation of the results. We also calculated Pu amount in the spent fuel by ORIGEN code based on declared burn up. Based on the two different evaluations for Pu amount, we found that there is 7% difference between NOVA and ORIGEN code. It is summarized that there is possibility of developed method being used newly burn up monitoring and safeguards technique.
Okano, Masanori; Kuno, Takehiko; Takahashi, Ichiro*; Charlton, W. S.*; Wells, C. A.*; Hemberger, P. H.*
46th Annual Meeting of the INMM, Final Program, Abstract 352, 0 Pages, 2005/07
We have studied a new technique to evaluate Pu amount in the spent fuel from Xe isotopic ratio in off-gas in reprocessing facility, which is related to burn up. The technique is applicable for both burn up credit to achieve efficient criticality safety control and a new measurement method for safeguards inspection. Six batches of dissolver off-gas (DOG) at spent fuel dissolution process were sampled with press pump from the main stack in Tokai Reprocessing Plant (TRP) during BWR fuel (approx. 30GWD/MTU) reprocessing campaign. Xe isotopic ratio was determined with Gas Chromatography-Quadrupole Mass Spectrometer (GC-QMS). Burn up and Pu amount were evaluated with NOVA, Noble Gas Environmental Monitoring Application code, developed by Los Alamos National Laboratory. Agreement between declared burn up and inferred burn up evaluated by Xe isotopic measurements and NOVA was at the 94% confidence level. We found that Pu amount in spent fuel evaluated by developed method agreed with declared value calculated by ORIGEN code in the range of -0.9% to 4.7%.
Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.
Proceedings of INMM 46th Annual Meeting (CD-ROM), 8 Pages, 2005/00
JAERI has been developing analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. Development of essential techniques for bulk and particle analysis of the environmental swipe sample has been established as an ultra-trace analytical method of uranium and plutonium. In January 2003, JAERI was qualified as a member of the IAEA network analytical laboratories for environmental samples. Since then, JAERI has conducted the analysis of domestic and the IAEA samples. From Japanese fiscal year 2003, the second phase of the project was started for the development of advanced techniques, such as analyzing minor actinides and fission products as well as uranium and plutonium, particle analysis using fission-track technique, more efficient particle analysis using ICP-TOFMS and screening by X-ray fluorescent analysis. This paper deals with the progress in the development of the new techniques, applications and future perspective.