First-principles study of fission product (Xe, Cs, Sr) incorporation and segregation in alkaline earth metal oxides, HfO2, and the MgO–HfO2 interface
First-principles study of fission product (Xe, Cs, Sr) incorporation and segregation in alkaline earth metal oxides, HfO2, and the MgO–HfO2 interface
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碱土金属氧化物、HfO2 和 MgO-HfO2 界面中裂变产物（Xe、Cs、Sr）掺入和偏析的第一性原理研究
DOI：
10.1088/0953-8984/21/4/045403
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
K. Sickafus
中科院分区：
文献类型：
--
作者：
Xiang;B. Uberuaga;K. Sickafus
为了关闭核燃料循环，需要分离裂变产物的先进概念。一种方法是使用弥散燃料形式，其中裂变堆芯被惰性基质包围，惰性基质捕获并固定来自堆芯的裂变产物。如果这种惰性基质可以通过例如溶液化学容易地与燃料分离，则裂变产物可以与裂变材料分离。我们研究的替代分散燃料组合物，其中氧化铪（HfO 2）是一个替代品的裂变核心和碱土金属氧化物被用作惰性基质。裂变产物纳入这些氧化物和可能的偏析行为在界面上的问题被认为是。基于密度泛函理论的计算裂变产物元素（锶，锶，铯）在这些氧化物进行。我们发现较小的掺入能量在氧化镁比在氧化镁的Cs和Sr，和SiO2，如果电荷状态的变化是允许的。我们还发现，这种趋势是逆转或减少碱土金属氧化物与大阳离子尺寸。模型界面计算显示出强烈的倾向，从散装MgO的MgO-HfO 2界面偏析。
In order to close the nuclear fuel cycle, advanced concepts for separating out fission products are necessary. One approach is to use a dispersion fuel form in which a fissile core is surrounded by an inert matrix that captures and immobilizes the fission products from the core. If this inert matrix can be easily separated from the fuel, via e.g. solution chemistry, the fission products can be separated from the fissile material. We examine a surrogate dispersion fuel composition, in which hafnia (HfO2) is a surrogate for the fissile core and alkaline earth metal oxides are used as the inert matrix. The questions of fission product incorporation in these oxides and possible segregation behavior at interfaces are considered. Density functional theory based calculations for fission product elements (Xe, Sr, and Cs) in these oxides are carried out. We find smaller incorporation energy in hafnia than in MgO for Cs and Sr, and Xe if variation of charge state is allowed. We also find that this trend is reversed or reduced for alkaline earth metal oxides with large cation sizes. Model interfacial calculations show a strong tendency of segregation from bulk MgO to MgO–HfO2 interfaces.