Long-term evolution of plutonium waste-form candidates, with focus on radiation effects on dissolution behaviour.

锆英石陶瓷和处置混合氧化物废物由于其极低的溶解度，对标准溶解测试规程构成了挑战。因此，有必要开发方法来充分测试陶瓷废物的耐久性，以进行比较，以及开发一个强大的数据集，以证明产品性能的充分机械理解，并定量确定溶解速率。在此背景下，仍然存在重要但未解决的哲学问题，例如：辐射损伤诱导的晶态到非晶态相变是否（或在MOX的情况下，氧空位缺陷的诱导）导致增强的溶解速率;中子毒物是否以与U/Pu（Ce/Th）相同的速率释放;水的α辐解如何影响铀/钚在锆英石陶瓷中的腐蚀和处理MOX废物。人们认识到，测试方法的开发和优化还应着眼于在手套箱环境中对钚原型废物进行部署，并适用于一次性混合氧化物配方。这个博士项目将探讨这些方面的钚废物形式候选陶瓷溶解，重点是辐射的作用。

Zirconolite ceramic and disposal MOX wasteforms pose a challenge to standard dissolution test protocols given their extremely low solubility. Hence, there is a need to develop methodologies to adequately test ceramic wasteform durability, for the purpose of comparison, as well as to develop a robust data set to demonstrate an adequate mechanistic understanding of product performance, and to quantitatively determine dissolution rates. In this context, there remain important but unresolved philosophical questions, such as: whether the radiation damage-induced crystalline to amorphous phase transition (or in the case of MOX, induction of oxygen vacancy defects) results in enhanced dissolution rates; whether neutron poisons are released at the same rate as U/Pu(Ce/Th) and; how alpha radiolysis of water influences the corrosion of U/Pu in zirconolite ceramic and disposal MOX wasteforms. There is an appreciation that development and optimisation of test methodologies should also look ahead to deployment against Pu prototype wasteforms within a glove box environment, and for applicability to disposal-MOX formulations. This PhD project will explore these aspects of plutonium waste form candidate ceramic dissolution, with emphasis on the role of radiation.