| DOI: | 10.2172/1027978
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| 报告号: | LLNL-TR-464651
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| 报告题名: | Neptunium Transport Behavior in the Vicinity of Underground Nuclear Tests at the Nevada Test Site |
| 作者: | Zhao, P; Tinnacher, R M; Zavarin, M; Williams, R W; Kersting, A B
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| 出版年: | 2010
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| 发表日期: | 2010-12-03
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| 总页数: | 23
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| 国家: | 美国
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| 语种: | 英语
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| 中文主题词: | 同位素
; 放射性核素
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| 主题词: | ISOTOPES
; RADIONUCLIDES
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| 英文摘要: | We used short lived {sup 239}Np as a yield tracer and state of the art magnetic sector ICP-MS to measure ultra low levels of {sup 237}Np in a number of 'hot wells' at the Nevada National Security Site (NNSS), formerly known as the Nevada Test Site (NTS). The results indicate that {sup 237}Np concentrations at the Almendro, Cambric, Dalhart, Cheshire and Chancellor sites, are in the range of 3 x 10{sup -5} to 7 x 10{sup -2} pCi/L and well below the MCL for alpha emitting radionuclides (15 pCi/L) (EPA, 2009). Thus, while Np transport is believed to occur at the NNSS, activities are expected to be well below the regulatory limits for alpha-emitting radionuclides. We also compared {sup 237}Np concentration data to other radionuclides, including tritium, {sup 14}C, {sup 36}Cl, {sup 99}Tc, {sup 129}I, and plutonium, to evaluate the relative {sup 237}Np transport behavior. Based on isotope ratios relative to published unclassified Radiologic Source Terms (Bowen et al., 1999) and taking into consideration radionuclide distribution between melt glass, rubble and groundwater (IAEA, 1998), {sup 237}Np appears to be substantially less mobile than tritium and other non-sorbing radionuclides, as expected. However, this analysis also suggests that {sup 237}Np mobility is surprisingly similar to that of plutonium. The similar transport behavior of Np and Pu can be explained by one of two possibilities: (1) Np(IV) and Pu(IV) oxidation states dominate under mildly reducing NNSS groundwater conditions resulting in similar transport behavior or (2) apparent Np transport is the result of transport of its parent {sup 241}Pu and {sup 241}Am isotopes and subsequent decay to {sup 237}Np. Finally, measured {sup 237}Np concentrations were compared to recent Hydrologic Source Term (HST) models. The 237Np data collected from three wells in Frenchman Flat (RNM-1, RNM-2S, and UE-5n) are in good agreement with recent HST transport model predictions (Carle et al., 2005). The agreement provides confidence in the results of the predictive model. The comparison to Cheshire HST model predictions (Pawloski et al, 2001) is somewhat ambiguous due to the low concentration resolution of the particle transport model. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1027978
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/39597
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| 1027978.pdf（1106KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Zhao, P,Tinnacher, R M,Zavarin, M,et al. Neptunium Transport Behavior in the Vicinity of Underground Nuclear Tests at the Nevada Test Site. 2010-01-01.
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