Burnup determination and age dating of spent nuclear fuel using noble gas isotopic analysis
During the chopping and dissolving phases of reprocessing, gases (such as tritium, krypton, xenon, iodine, carbon dioxide, nitrogen oxide, and steam) are released. These gases are traditionally transferred to a gas-treatment system for treatment, release, and/or recycle. Because of their chemically inert nature, the xenon and krypton noble gases are generally released directly into the loser atmosphere through the facility's stack. These gases (being fission products) contain information about the fuel being reprocessed and may prove a valuable monitor of reprocessing activities. Two properties of the fuel that may prove valuable from a safeguards standpoint are the fuel burnup and the fuel age (or time since discharge from the reactor). Both can be used to aid in confirming declared activities, and the burnup is generally indicative of the usability of the fuel for fabricating nuclear explosives. A study has been ongoing at Los Alamos National Laboratory to develop a methodology to determine spent-fuel parameters from measured xenon and/or krypton isotopic ratios on-stack at reprocessing facilities. This study has resulted in the generation of the NOVA data analysis code, which links to a comprehensive database of reactor physics parameters (calculated using the Monteburns 3.01 code system). NOVA has been satisfactorily tested for burnup determination of weapons-grade fuel from a US production reactor. Less effort has been spent quantifying NOVA's ability to predict burnup and fuel age for power reactor fuel. The authors describe the results predicted by NOVA for xenon and krypton isotopic ratios measured after the dissolution of spent-fuel samples from the Borssele reactor. The Borssele reactor is a 450-MW(electric) pressurized water reactor (PWR) consisting of 15 x 15 KWU assemblies. The spent-fuel samples analyzed were single fuel rods removed from one assembly and dissolved at the La Hague reprocessing facility. The assembly average burnup was estimated at 32,540 MWd/tonne U.
- Research Organization:
- Los Alamos National Lab., TN (US)
- OSTI ID:
- 20005836
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 81; Conference: American Nuclear Society 1999 Winter Meeting, Long Beach, CA (US), 11/14/1999--11/18/1999; Other Information: PBD: 1999; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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