Alteration of Natural UO2 under Oxidizing Conditions from Shinkolobwe, Katanga, Zaire: A Natural Analogue for the Corrosion of Spent Fuel
Alteration of Natural UO2 under Oxidizing Conditions from Shinkolobwe, Katanga, Zaire: A Natural Analogue for the Corrosion of Spent Fuel
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来自 Shinkolobwe、加丹加、扎伊尔的天然 UO2 在氧化条件下的变化：乏燃料腐蚀的天然类似物
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发表时间：
1991
期刊：
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通讯作者：
R. Ewing
中科院分区：
文献类型：
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作者：
R. Finch;R. Ewing
对与高放核废料储存库接触的地下水化学进行长期预测建模需要对废U 0 2 燃料的含铀固体蚀变相进行表征。扎伊尔 Shinkolobwe 铀矿 (U 0 2 +,) 的蚀变为乏核燃料与氧化性地下水接触的腐蚀提供了天然的类似物。使用光学显微镜、扫描电子显微镜、分析电子显微镜、X 射线衍射分析和电子微探针分析对铀矿蚀变产物进行综合分析，表明在所有分析尺度上都存在共存相。铀酰硅酸盐 uranophane (H30)2Ca(U02)2(SiO4)2 · 3 H 2 0 和白铜矿 (H30)2Cu(U02)2(Si04)2 · 4 H 2 0 在研究的样品中普遍存在，并取代氧化铀酰贝克勒石 Ca(U0 2 ) 6 0 4 (0H) 6 • 8 H 2 0 , 镁镁铝矿 K 2 ( U 0 2 ) 6 0 4 ( 0 H ) 6 · 8 H 2 0 , 钒镁石 P b U 7 0 2 2 • 22H 2 0 , 镁镁石 PbU 4 0 1 3 • 6 H 2 0 , 镁锂石 Ba(U02)60通过氧化物水合物与富含二氧化硅的地下水反应生成4 ( 0 H ) 6 · 8 H 2 0 和软云母U 0 3 · 2 H 2 0 。随着蚀变的进行，晶粒尺寸明显减小。
Characterization of the uranium-containing solid alteration phases of spent U 0 2 fuel is required for the long term predictive modeling of groundwater chemistries in contact with a high-level nuclear waste repository. The alteration of uraninite ( U 0 2 +,) at Shinkolobwe, Zaire provides a natural analogue for the corrosion of spent nuclear fuel in contact with oxidizing groundwater. An integrated analysis of uraninite alteration products using optical microscopy, scanning electron microscopy, analytical electron microscopy, X-ray diffraction analysis, and electron microprobe analysis demonstrates the presence of coexisting phases at all analytical scales. The uranyl silicates uranophane (H30)2Ca(U02)2(Si04)2 · 3 H 2 0 and cuprosklodowskite (H30)2Cu(U02)2(Si04)2 · 4 H 2 0 are ubiquitous in the samples studied and replace the uranyl oxide hydroxides becquerelite Ca(U0 2 ) 6 0 4 (0H) 6 • 8 H 2 0 , compreignacite K 2 ( U 0 2 ) 6 0 4 ( 0 H ) 6 · 8 H 2 0 , vandendriesscheite P b U 7 0 2 2 • 22H 2 0 , fourmarierite PbU 4 0 1 3 • 6 H 2 0 , billietite Ba(U02)60 4 ( 0 H ) 6 · 8 H 2 0 , and schoepite U 0 3 · 2 H 2 0 by reaction of the oxide hydrates with silica-rich groundwater. A reduction in grain size is apparent as alteration proceeds.