The Development of Advanced Technologies and Modelling Capabilities to Improve the Safety and Performance of Nuclear Fuel

开发先进技术和建模能力以提高核燃料的安全性和性能

基本信息

批准号：
EP/I003320/1
负责人：
Timothy Abram
金额：
$ 148.35万
依托单位：
University of Manchester
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FI003320%2F1
关键词：
Development Advanced Technologies Modelling Capabilities

项目摘要

The main factors that limit the performance of nuclear fuels are related to cladding failure due to interactions with the fuel pellet and reactor coolant. Improvements to our understanding of the cladding failure mechanisms will enhance our ability to predict their effects, leading both to improvements in the safety and operation of current fuels, and to technological developments that will produce improved fuel, cladding, and coating materials. The research tasks below seek to address each of these issues in turn, from the perspective of both current and advanced fuel designs.Aomistic modelling research will focus on the input that atomic scale simulations make in describing the behaviour of micro-structural defects. This will refine our understanding of the fundamental physical processes that degrade fuel performance, and will result in improvements to current semi-empirical fuel performance models. The simulations will focus upon the interaction of fission products, radiation damage and dislocations, processes responsible for macroscopic observables such as fission gas release and irradiation induced creep.Fuel and cladding dimensional changes resulting from thermo-mechanical and irradiation conditions produce complex pellet-clad mechanical interactions (PCMI) that are known to cause fuel failure, especially under accident conditions. Models for PCMI failure based on ramp-test data have been developed, but these are highly empirical and therefore of limited applicability. However, advances in finite element (FE) modelling now permit the development of detailed models, and techniques such as the extended FE method can be applied to model crack growth and crack tip stresses and strains accurately whilst taking into account residual and applied stress redistribution. This research will investigate the development of pellet crack patterns and pellet-clad interface stresses under both normal and off-normal conditions. Mechanistic models for pellet failure and cladding damage will be developed.Research into composite cladding will investigate the potential for silicon carbide composites to provide significantly better performance compared with existing cladding materials. A new approach will be investigated, based on a solid SiC inner tube wrapped with SiC fibers and bonded using SiC vapour infiltration. The research will address fundamental aspects of this new concept, including: characterisation of the relationship between both design and manufacturing parameters and mechanical strength; ability of the tube to remain impermeable against fission products; and resistance to oxidation and fission product attack at high temperatures. Although UO2 has been used for many years as a fuel material, promising new materials have ben developed that could offer advantages in terms of safety and performance. The objective of this research is to identify alternative fuel materials and fuel forms; to evaluate their physical properties such as thermal conductivity; assess their reactivity with water using autoclave testing; and to assess industrially-feasible manufacturing routes. Candidate materials include alloys such as U3Si2, U-Mo, U-Zr and covalent compounds such as carbides and nitrides (in the latter case with additives to reduce the reaction rate in water). TRISO coated fuel particles manufactured by chemical vapour deposition (CVD) have demonstrated remarkable performance, but are known to be susceptible to attack by fission products such as Pa. This research will provide a fundamental understanding of these issues and will investigate alternative materials and processes to provide improved performance. The high temperature mechanical properties of coatings will be examined to understand the effects of manufacturing conditions. The mechanisms of fission product transport will be studied with a view to introducing materials and microstructural changes that will improve performance in this respect.

限制核燃料性能的主要因素与由于与燃料颗粒和反应堆冷却液相互作用而导致的覆层失败有关。改善我们对覆层失败机制的理解将增强我们预测其影响的能力，从而改善当前燃料的安全性和运营，以及将产生改善燃料，覆层和涂料材料的技术发展。下面的研究任务旨在从当前和高级燃料设计的角度来解决这些问题。敏化建模研究将集中于原子量表模拟在描述微观结构缺陷行为时所做的投入。这将完善我们对降低燃料性能的基本物理过程的理解，并将改善当前的半经验燃料性能模型。这些模拟将集中于裂变产物的相互作用，辐射损伤和错位的相互作用，负责宏观观察物的过程，例如裂变气体释放和辐照引起的蠕变。燃料和覆层尺寸变化导致热机械和辐照条件导致复杂的PELLET PELLET PELLET-CLAD机械相互作用（PCMI），尤其是燃料燃料造成的情况，尤其是事故。已经开发了基于坡道测试数据的PCMI故障模型，但是这些模型具有高度的经验性，因此适用性有限。但是，有限元（FE）建模的进步现在允许开发详细的模型，并且可以将诸如扩展的FE方法等技术应用于裂纹生长和裂纹尖端应力和应变，同时考虑到残留应力重新分配。这项研究将调查在正常条件和正常条件下，颗粒裂纹模式和胶囊界面应力的发展。将开发出沉淀和覆层损害的机械模型。研究复合覆层将研究与现有的覆层材料相比，碳化硅复合材料的潜力明显更好。基于用SIC纤维包裹并使用SIC蒸气浸润粘合的固体SIC内管，将研究一种新方法。该研究将解决这一新概念的基本方面，包括：设计与制造参数与机械强度之间的关系的表征；管子对裂变产物保持不可渗透的能力；以及在高温下抗氧化和裂变产物攻击的能力。尽管UO2已被用作燃料材料多年，但Ben开发的有希望的新材料可以在安全性和性能方面具有优势。这项研究的目的是确定替代燃料材料和燃料形式。评估其物理特性，例如导热率；使用高压釜测试评估其对水的反应性；并评估工业可行的制造路线。候选材料包括合金，例如U3SI2，U-MO，U-ZR和共价化合物，例如碳化物和氮化物（在后一种情况下，添加剂以降低水的反应速率）。化学蒸气沉积（CVD）生产的Triso涂层燃料颗粒表现出了显着的性能，但已知很容易受到PA等裂变产品的攻击。这项研究将提供对这些问题的基本了解，并将研究替代材料和过程以提供改进的性能。将检查涂料的高温机械性能，以了解制造条件的影响。将研究裂变产品运输的机制，以引入材料和微结构变化，以改善这方面的性能。