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地下水流数值模拟是高放废物处置库选址中水文地质评价的重要内容。水文地质概念模型是地下水流数值模拟的基础和前提。在北山预选区水文地质分析基础上,利用DEM数据生成了研究区地表水系,据此确定了模拟范围;借助GMS软件,建立了研究区三维水文地质结构模型;再通过边界条件、流场特征、地下水均衡项和水文地质参数的分析和描述,建立了北山地区水文地质概念模型。 相似文献
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在野外水文地质调查基础上,开展了北山地区地下水系统特征、岩体渗透性能、地下水动态、水文地球化学、地下水同位素、地下水CFC以及地下水流场模拟等综合性水文地质研究。依据大量资料的科学分析,综合论述了研究区水文地质条件、地下水循环交替特征、地下水化学特征和动力学特征,并对北山地区作为高放废物处置库场址预选区的适宜性进行了评价。通过这些工作,不仅为我国高放废物地质处置库选址建立了系统的水文地质研究和评价方法,也为在该区筛选最适宜的高放废物处置库场址提供了重要的水文地质依据。 相似文献
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深地质处置是目前国际上普遍接受的高放废物最终处置方案。对于这种处置方案而言,最有可能使处置库系统中放射性核素释放并进入生物圈的机制是地下水的作用。本文阐述了这种地下水的作用,包括地下水与工程屏障的相互作用、地下水在地质屏障中的核素迁移作用及核素滞留作用;介绍了处置库场址评价中水文地质研究的国际进展和动向;重点介绍了我国高放废物处置库预选场址水文地质研究进程和概况。 相似文献
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新疆雅满苏和天湖地区是我国高放废物处置库场址的主要预选地段之一。在高放废物处置库选址和评价中,水文地球化学特征是最重要的评价因素之一。在2009-2013年间,开展了雅满苏和天湖地段区域水文地球化学调查,采集地下水样品30余组,根据样品测试结果,讨论了该地区水文地球化学特征,其主要结论是:研究区地下水主要为高矿化的咸水。地下水的pH=7.69~9.64;水温11.8~24.0℃;地下水矿化度(TDS)在542.7~413375.5 mg/L之间变化,地下水的主要化学类型为Cl•SO4-Na、SO4•Cl-Na和Cl-Na型。控制地下水化学形成的主要作用是溶滤作用和蒸发浓缩作用。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(7):1069-1076
In Japan, uplift/erosion scenarios must be analysed even if they occur far in the future, as no assessment cut-off times have yet been defined. For this purpose, the geological record of river terrace formation and their long-term evolution have been studied further, with the aim of constructing a better defined fluvial erosion model than the original, rather simple cyclic fluvial erosion model developed in a previous study. The developed conceptual model, based on a generalization of field observations in relevant settings, allows the consequences of erosion of the repository to be assessed just as before, using comparisons with natural radionuclide fluxes. Results illustrate the effectiveness and robustness of the H12 HLW disposal system and indicate that erosion scenarios are unlikely to be critical for distinguishing between different sites that lie in similar mid-range river settings. 相似文献
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铀在特定场址地下水中存在和迁移形态研究及其沉积热力学分析 总被引:8,自引:2,他引:8
将化学热力学平衡分析模式与地球化学条件相结合,应用铀元素水文地球化学迁移形式热力学分析方法,计算出某特定场址地下水中铀的化学形态和迁移形态。结果表明:UO2(CO3)2^2-占84.1%,UO2(CO3)^0占8.7%,UO2(CO2)3^-占6.5%。 相似文献
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为了解铀酰离子在北山地下水中的吸附、扩散和迁移行为,利用地球化学计算软件PHREEQC,采用由OECD/NEA发布的最新铀的热力学数据,计算了铀在我国高放废物地质处置库重点研究区甘肃北山地下水中的种态分布,并分析了围岩中存在的方解石对铀溶解度的影响。计算结果表明,在北山地下水组成不变的前提下,在偏酸性条件下,铀主要以UO2F+、UO2SO4、UO22+、UO2F2和UO2(SO4)22-的形式存在,而在中性至弱碱性条件下,主要以 UO2(CO3)4-3、UO2(CO3)22-、UO2(OH)3-和UO2(OH)42-的形式存在。我国计划建造的高放废物处置库的设计深度为地下500~1000m,其水岩体系一般呈弱碱性。在这样的弱碱性水岩体系中,以阴离子形式存在的铀酰配合物具有较强的可移动性。当地下水的pH=7.56时,在Eh<24mV的条件下,铀主要以沥青铀矿的形式存在,而在更高的Eh条件下,则主要以UO22+与CO32-和OH-形成的阴离子配合物的形式存在。当地下水与空气接触时,O2的存在会使Eh升高,此时铀的主要存在种态为UO22+及其各种配合物。当围岩体系中存在方解石时,在pH<8.0的条件下,铀在地下水中的溶解度会显著提高,而在更高pH条件下,方解石对铀的溶解度无明显影响。 相似文献
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铀尾矿库区浅层地下水中U(Ⅵ)迁移的模拟 总被引:2,自引:0,他引:2
在详细分析中国南部某大型铀水冶尾矿库的结构特点、运营情况和库区水文地质条件的基础上,对库区水文地质条件进行概述,运用溶质反应-运移模拟软件PHREEQC-Ⅱ,建立研究区U(Ⅵ)在浅层地下水中迁移的一维溶质反应-输运耦合模型,并分析在不同时间、距离、扩散系数、弥散度等条件下铀在铀尾矿库区浅层地下水中的迁移,即铀浓度随时间及距离的变化。模拟结果与现场观测资料基本吻合,表明该软件能较好地模拟U(Ⅵ)的迁移情况,证明了该模型的可行性。研究还表明,弥散作用对铀迁移有显著影响,弥散度的取值是模拟可靠与否的关键参数,而分子扩散对本模拟的影响可忽略不计。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):929-937
Safety and uncertainty analyses for the shallow-land disposal of uranium wastes were performed using the deterministic and probabilistic safety assessment models. The analyses for uranium accumulated with 4.5% enrichment show that the doses in residence scenario are of great importance in the safety assessment owing to the influence of daughters built up by uranium decay chain. The dose in residence scenario is sensitive to the release condition of radionuclides from the facilities over long-term period. The parameter uncertainties for the important pathways in residence scenario are estimated from the probabilistic analyses using the statistical methodology. The uncertainty analysis indicates that the influence of parameter uncertainty is the most remarkable in the estimation for the inhalation of radon gas with residence. The parameter importance in each exposure pathway is estimated from using the partial rank correlation coefficients (PRCCs) between variable parameters and the evaluated doses. The important parameters identified by the PRCCs are depth of intrusion, infiltration rate, thickness of covered soil, diffusion coefficient of radon in soil etc. for the inhalation exposure of radon. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(3):398-404
Benefit of implementing Partitioning and Transmutation (P&T) technology was parametrically surveyed in terms of high-level radioactive waste (HLW) disposal by discussing possible reduction of the geological repository area. First, the amount and characteristics of HLWs caused from UO2 and MOX spent fuels of light-water reactors (LWR) were evaluated for various reprocessing schemes and cooling periods. The emplacement area in the repository site required for the disposal of these HLWs was then estimated with considering the temperature constrain in the repository. The results showed that, by recycling minor actinides (MA), the emplacement area could be reduced by 17–29% in the case of UO2-LWR and by 63–85% in the case of MOX-LWR in comparison with the conventional PUREX reprocessing. This significant impact in MOX fuel was caused by the recycle of 241Am which was a long-term heat source. Further 70–80% reduction of the emplacement area in comparison with the MA-recovery case could be expected by partitioning the fission products (FP) into several groups for both fuel types. To achieve this benefit of P&T, however, it is necessary to confirm the engineering feasibility of these unconventional disposal concepts. 相似文献