Continental-scale enrichment of atmospheric 14CO2 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2
Continental-scale enrichment of atmospheric 14CO2 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2
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DOI：
10.5194/acp-11-12339-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Gruber, N.
中科院分区：
文献类型：
--
作者：
Graven, H. D.;Gruber, N.
燃烧过程中添加到大气二氧化碳中的无碳 - 14的化石碳稀释了大气中的碳 - 14/碳比率（Δ碳 - 14），这可能为验证利用经济清单计算出的化石二氧化碳排放提供一种方法。然而，来自核能发电和乏燃料后处理的碳 - 14来源会抵消这种稀释作用，如果这些核影响没有得到正确考虑，可能会使基于碳 - 14/碳的化石燃料衍生二氧化碳估算产生偏差。先前的研究已经在局部范围内考察了核影响，但在大陆尺度上对Δ碳 - 14的潜在影响尚未得到探究。我们估算了世界上每个核设施的年度碳 - 14排放量，并进行了一项欧拉传输模拟研究，以调查由核活动和化石燃料燃烧引起的Δ碳 - 14在大陆尺度上的稳态梯度。在欧洲、北美洲和东亚的大片地区，核富集可能抵消Δ碳 - 14中至少20%的化石燃料稀释作用，这相当于在归因于化石燃料排放的二氧化碳中可能存在超过 - 0.25 ppm的偏差，在某些地区比植物和土壤呼吸产生的偏差还要大。尽管模型分辨率较粗，为1.8度×1.8度，但包含高碳 - 14释放反应堆或燃料后处理场所的模型网格单元显示出大得多的核富集。1985 - 2005年期间核碳 - 14排放的近期增长增加了潜在的核偏差，这表明核活动的变化可能会使利用Δ碳 - 14观测来确定化石燃料排放趋势的工作变得复杂。在大陆尺度的欧拉传输和反演研究背景下，潜在核偏差的大小在很大程度上与参考站的选择无关，但在局部尺度评估背景下，通过适当选择参考站可能会降低偏差。
The C-14-free fossil carbon added to atmospheric CO2 by combustion dilutes the atmospheric C-14/C ratio (Delta C-14), potentially providing a means to verify fossil CO2 emissions calculated using economic inventories. However, sources of C-14 from nuclear power generation and spent fuel reprocessing can counteract this dilution and may bias C-14/C-based estimates of fossil fuel-derived CO2 if these nuclear influences are not correctly accounted for. Previous studies have examined nuclear influences on local scales, but the potential for continental-scale influences on Delta C-14 has not yet been explored. We estimate annual C-14 emissions from each nuclear site in the world and conduct an Eulerian transport modeling study to investigate the continental-scale, steady-state gradients of Delta C-14 caused by nuclear activities and fossil fuel combustion. Over large regions of Europe, North America and East Asia, nuclear enrichment may offset at least 20% of the fossil fuel dilution in Delta C-14, corresponding to potential biases of more than -0.25 ppm in the CO2 attributed to fossil fuel emissions, larger than the bias from plant and soil respiration in some areas. Model grid cells including high C-14-release reactors or fuel reprocessing sites showed much larger nuclear enrichment, despite the coarse model resolution of 1.8 degrees x 1.8 degrees. The recent growth of nuclear C-14 emissions increased the potential nuclear bias over 1985-2005, suggesting that changing nuclear activities may complicate the use of Delta C-14 observations to identify trends in fossil fuel emissions. The magnitude of the potential nu-clear bias is largely independent of the choice of reference station in the context of continental-scale Eulerian transport and inversion studies, but could potentially be reduced by an appropriate choice of reference station in the context of local-scale assessments.