Proton, alpha and gamma irradiation assisted stress corrosion cracking: understanding the fuel-stainless steel interface

The student involved in this project will undertake an experimental research programme aimed at understanding radiation-driven mechanisms which lead to cracking of protective layers in spent fuels. The experimental programme will take place in UTGARD Lab at Lancaster University and at the Dalton Cumbrian Facility, the latter being a leading radiation science laboratory which is situated close to the heart of the UK nuclear industry. This will involve the irradiation of samples and development of their corrosion susceptibility in real time. The student involved will also perform complimentary modelling calculations, using state-of[1]the-art radiation transport and reaction-diffusion modelling software (SRIM calculations). Instruction in both the implementation of the irradiation and in the use of the modelling software will be provided in the first year of the PhD. The skills developed and the project location will make it ideal for someone with a longer-term ambition of entering the nuclear industry. Spent UK nuclear reactor fuel will be stored for at least 60 years before going into a Geological Disposal Facility (GDF). The cladding should not breach during this time. A better understanding of the effects of radiation, hydrogen, stress and water-environment is required to ensure safe storage and handling before the spent fuel is deposited in a GDF. Mechanisms underpinning crack growth, the precursor to cladding breach, are unknown and effects of stress are not currently well understood. The project will aim to develop a much better understanding of the processes at work. Proton irradiation of samples will be used in the first instance to expose them to reactor-levels of radiation damage. Subsequently, alpha and gamma irradiation will be used to mimic the damage effects caused by the fuel decay products. Radiation produces material damage and also changes in the water chemistry, producing highly reactive of oxidising species in a way which is distinct for each radiation type, hence the need for use of the various types of radiation. This combination is only available within the UK at DCF. This radiolytic production or reactive species in turn increases the corrosion potential which can initiate or accelerate crack formation and propagation. Microstructural effects manifest as key changes in the physico-chemical environment near grain boundaries, formation of dislocation loops, voids and precipitates, deformation and hardening. Through combining a range of techniques, including monitoring of electrochemical properties, chemical products and microscopy, it is hoped that precursors of crack-formation can be detected. This would in turn constitute a new candidate for on-site monitoring of spent fuels and hence make an important contribution to the UK's low-carbon energy provision.

参与该项目的学生将进行一项实验研究计划，旨在了解辐射驱动的机制，从而导致消耗燃料中的保护层破裂。实验计划将在兰开斯特大学的UTGARD实验室和道尔顿坎布里安设施举行，后者是领先的辐射科学实验室，位于英国核工业中心附近。这将涉及样品的照射以及实时的腐蚀敏感性的发展。参与的学生还将使用最新的[1]辐射传输和反应扩散建模软件（SRIM计算）执行免费建模计算。在博士的第一年，将提供辐射的实施和使用建模软件的指导。开发的技能和项目位置将使它成为具有长期野心进入核工业的人的理想选择。在进入地质处置设施（GDF）之前，花费的英国核反应堆燃料将至少存储60年。在此期间，壁板不应违反。需要更好地理解辐射，氢，压力和水环境的影响，以确保在将用过的燃料沉积在GDF中之前，确保安全存储和处理。裂纹生长的基础的机制，即违反裂纹的前体，尚不清楚，目前尚不清楚压力的影响。该项目将旨在更好地了解工作过程中的过程。首先将使用样品的质子照射将其暴露于反应器级别的辐射损伤中。随后，Alpha和Gamma辐照将用于模仿燃料衰减产物引起的损伤效应。辐射会产生材料损伤，并在水化学中发生变化，以每种辐射类型的不同方式产生高度反应性的氧化物种，因此需要使用各种类型的辐射。这种组合仅在英国在DCF内可用。这种放射性物质产生或反应性物种又增加了腐蚀潜力，从而启动或加速裂纹形成和繁殖。微观结构效应表现为物理化学环境附近的关键变化，位错环，空隙和沉淀物，变形和硬化的形成。通过结合一系列技术，包括监测电化学性能，化学产品和显微镜，希望能够检测到裂纹形成的前体。反过来，这将构成现场监测用过的燃料的新候选人，因此为英国的低碳能源提供了重要贡献。