Radiation damage effects in amorphous zirconolite
Radiation damage effects in amorphous zirconolite
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DOI：
10.1016/j.jnucmat.2020.152654
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发表时间：
2021-01-02
影响因子：
3.1
通讯作者：
Trachenko, K.
中科院分区：
文献类型：
--
作者：
Diver, A.;Dicks, O.;Trachenko, K.
我们报道了一项关于锆石核废料中辐射损伤效应的大规模模拟研究的结果。我们特别关注了非晶态锆石的辐射损伤效应，并发展了一种从局域配位统计的角度分析损伤结构的新方法。在此基础上，我们发现非晶态结构对辐射损伤的响应不同于晶体结构。研究发现，非晶态的锆石比晶态的锆石“软”，在70keV的级联过程中，有更多的原子发生位移并改变配位。局部配位和连接性分析表明，由于反复辐射损伤，非晶态结构继续演变，这种变化不能从对分布函数等全局平均性质中识别出来。我们还发现了地方一级的大密度不均匀，我们认为这可能对核废料储存的未来发展起到重要作用。最后，我们发现了热变和局域配位之间的关系，这表明测量热变可以定量地与结构辐射损伤联系起来。我们的结果提出了一个有趣的可能性，即辐射损伤导致的非晶态结构的演化是否会收敛到一个新的平衡非晶态区域，这就提出了这个结构可能是什么的根本问题。(C)2020爱思唯尔B.V.保留所有权利。
We report the results of a large-scale modelling study of radiation damage effects in the nuclear waste form zirconolite. We particularly focus on the effects of radiation damage in amorphous zirconolite and have developed a new way to analyse the damaged structure in terms of local coordination statistics. On the basis of this analysis, we find that the amorphous structure responds to radiation damage differently from the crystal. Amorphous zirconolite is found to be "softer" than crystalline zirconolite with a much larger number of atoms becoming displaced and changing coordination during a 70 keV cascade. The local coordination and connectivity analysis shows that the amorphous structure continues to evolve as a result of repeated radiation damage, changes which cannot be identified from globally averaged properties such as pair distribution functions. We also find large density inhomogeneities at the local level which we suggest may play an important role for future developments in nuclear waste storage. Finally, we find a correlation between the changes in enthalpy and local coordination, suggesting that measurements of enthalpy change can be linked quantitatively to structural radiation damage. Our results raise an interesting possibility of whether an evolution of the amorphous structure due to radiation damage can converge to a new equilibrium amorphous regime, posing the fundamental question of what that structure may be. (C) 2020 Elsevier B.V. All rights reserved.