Understanding Radiation Induced Transmutation in Tungsten Alloys for Nuclear Fusion

了解核聚变钨合金中的辐射诱发嬗变

• 批准号: 1802461
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1802461
• 关键词: Understanding; Radiation; Induced; Transmutation; Tungsten

The development of viable nuclear fusion power plants relies on materials capable of withstanding the combined effects of high neutron irradiation and elevated temperatures in an extreme environment around the fusion plasma. Few materials proposed for plasma-facing components are capable of meeting these demands. Molybdenum, carbon composites and beryllium have all been examined but issues with either activation, tritium retention or sputtering rate exist for all these. Tungsten is now considered the leading candidate for the divertor and possibly all first wall armour. During irradiation with 14MeV neutrons, transmutation effects will alter the composition of any materials, further complicating accurate predictions of lifetime assessment. Previous work has shown that binary tungsten -rhenium and tungsten -tantalum alloys can form nanosized precipitates under irradiative exposures, which harden then ultimately embrittle the materials. However ternary W-Re-Ta and W-Re-Os alloys have been shown to behaviour quite differently under irradiation which raises important questions about the best route for mimicking transmutation pathways using pre-alloyed materials and fundamental questions regarding the mechanisms of precipitation formation in both irradiated and unirradiated alloys. In addition there have been no studies of tungsten-rhenium-tantalum-osmium alloys despite this being the terminal composition, previous studies focused on binary systems only and sometimes with overly high solute contents. This can lead to precipitates being observed that are not expected under operational conditions. In this project, higher-order (both ternary and quaternary alloys from the of tungsten-rhenium-tantalum-osmium systems) alloys representing more accurate transmutation products will be exposed to heavy ion-irradiation, then examined using a multi-technique approach of Atom Probe Tomography, TEM and Nanoindentation Measurements, aiming to link 3D chemical information at the atomic-scale to mechanical properties of these alloys. In particular how thermally stable these clusters are will be studied using thermal aging treatments. There has been no studies performed on this system with respect to this and this will be the first time the dissolution or growth will be observed. Nanoindentation will be used to study the interaction of dislocations with clusters and how this lead to hardening. These experiments are key to understanding if thermal treatments can be used to prolong divertor lifetime in service by annealing out radiation damage.In this manner we hope to obtain a much deeper understanding of interactions between solute additions in these materials following irradiation, better understand the kinetics and thermodynamics of irradiation assisted precipitation and how this alters the mechanical behaviour. This will provide valuable data needed to underpin atomistic simulations being performed at CCFE and eventually lead to better lifeing predictions for the divertor.EPSRC research theme is Energy.

可行的核融合发电厂的发展取决于能够承受高中子照射和融合等离子体周围极端环境中温度升高的综合作用。面向等离子体的组件提出的材料很少能够满足这些要求。所有这些都已经检查了钼，碳复合材料和铍，但所有这些都存在激活，tritium保留或溅射率的问题。现在，钨被认为是转移者和所有第一墙装甲的领先候选人。在用14MEV中子辐照过程中，trans变效应将改变任何材料的组成，从而使对终生评估的准确预测更加复杂。先前的工作表明，二元钨 - 雷氏菌和钨 - 塔坦合金可以在辐照式暴露下形成纳米沉淀物，这最终使材料最终脱离了材料。但是，在辐射下，三元W-RE-TA和W-RE-OS合金的行为已大不相同，这引发了有关使用预合金材料模仿trans变途径的最佳途径的重要问题，以及有关辐射和未辐照的Alloys中降水形成机制的基本问题。此外，尽管如此，尽管如此，还没有研究tungsten-rhenium-tantalum-osmium合金，尽管这是末端组成，但先前的研究仅集中在二元系统上，有时甚至具有过高的溶质含量。这可能会导致观察到在操作条件下预期的沉淀。 In this project, higher-order (both ternary and quaternary alloys from the of tungsten-rhenium-tantalum-osmium systems) alloys representing more accurate transmutation products will be exposed to heavy ion-irradiation, then examined using a multi-technique approach of Atom Probe Tomography, TEM and Nanoindentation Measurements, aiming to link 3D chemical information at the atomic-scale to mechanical这些合金的特性。特别是如何使用热老化处理来研究这些簇的热稳定。关于此系统，没有对该系统进行的研究，这将是第一次观察到溶解或生长。纳米引导将用于研究错位与簇的相互作用，以及这如何导致硬化。这些实验是了解是否可以通过退火辐射损害来了解热处理是否可以用于延长移动寿命。在这种方式中，我们希望在辐射后对这些材料中溶质添加之间的相互作用有更深入的了解，更好地了解辐射量的动力学和热力学的辐射量辅助辅助辅助以及如何使机械行为进行整理。这将提供在CCFE进行的基础原子模拟所需的有价值的数据，并最终为转移者提供更好的生活预测。EPSRC研究主题是能源。

项目成果

Radiation-induced segregation in W-Re: from kinetic Monte Carlo simulations to atom probe tomography experiments

• DOI: 10.1140/epjb/e2019-100244-y
• 发表时间: 2019-10
• 期刊: The European Physical Journal B
• 作者: M. J. Lloyd;R. Abernethy;D. Armstrong;P. Bagot;M. Moody;E. Martínez;D. Nguyen-Manh

Decoration of Voids with Rhenium and Osmium Transmutation Products in Neutron Irradiated Single Crystal Tungsten

• DOI: 10.2139/ssrn.3389518
• 发表时间: 2019-05
• 期刊: AMI: Scripta Materialia
• 作者: M. J. Lloyd;R. Abernethy;I. Griffiths;P. Bagot;M. Moody;D. Armstrong;M. Gilbert