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Radiation damage effects in amorphous zirconolite
Journal of Nuclear Materials ( IF 2.8 ) Pub Date : 2020-11-08 , DOI: 10.1016/j.jnucmat.2020.152654
A. Diver , O. Dicks , I.T. Todorov , A.M. Elena , K. Trachenko

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.



中文翻译:

非晶锆石中的辐射损伤效应

我们报告了大规模建模研究的结果,对放射性废物在锆石形式的核废料中的损害进行了研究。我们特别关注无定形锆石中辐射损伤的影响,并已开发出一种新的方法,可以通过局部配位统计分析损伤结构。在此分析的基础上,我们发现非晶结构对辐射损伤的响应与晶体不同。发现无定形锆石比晶体锆石“更软”,在70 keV级联反应中,大量的原子被置换并改变了配位。局部配位和连通性分析表明,无定形结构由于反复受到辐射破坏而继续发展,无法从全局平均属性(例如对分布函数)中识别出的更改。我们还发现了地方一级的大密度不均匀性,我们认为这可能对核废料存储的未来发展起重要作用。最后,我们发现焓变与局部配位之间存在相关性,这表明焓变的测量值可以定量地与结构性辐射损伤联系起来。我们的结果提出了一个有趣的可能性,即由于辐射损伤而导致的非晶结构的演化是否可以收敛到新的平衡非晶态,从而提出了该结构可能是什么的根本问题。最后,我们发现焓变与局部配位之间存在相关性,这表明焓变的测量值可以定量地与结构性辐射损伤联系起来。我们的结果提出了一个有趣的可能性,即由于辐射损伤而导致的非晶结构的演化是否可以收敛到新的平衡非晶态,从而提出了该结构可能是什么的根本问题。最后,我们发现焓变与局部配位之间存在相关性,这表明焓变的测量值可以定量地与结构性辐射损伤联系起来。我们的结果提出了一个有趣的可能性,即由于辐射损伤而导致的非晶结构的演化是否可以收敛到新的平衡非晶态,从而提出了该结构可能是什么的根本问题。

更新日期:2020-11-09
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