Hydrogen embrittlement in fuel cladding in advanced candu and generation IV reactors

加拿大签署《京都议定书》和《悉尼协定》将需要做出相当大的努力来限制温室气体排放，从而依赖清洁能源。核能被认为是未来的清洁能源，新型先进的CANDU反应堆提供了更高的燃料消耗、更高的效率和极好的运行安全性。此外，加拿大正在设计第四代反应堆，这些反应堆也被认为是为生产清洁燃料氢气提供热量。这些先进反应堆的性能和高效率与较高的操作温度有关，必须做出重大努力来提高材料在高温环境下的性能和预期寿命。本建议旨在评估微观组织在燃料包壳氢脆中的作用，以提高燃料包壳在较高工作温度下的预期寿命。提出的研究目标是改进用于先进CANDU反应堆的Zircaloy-4覆层的工艺和组织，以及未来在IV代反应堆中应用的新型合金E110(Zr-1Nb)。新的定向成像实验技术尚未应用于包层脆化研究，这将使我们首次能够研究晶界结构在氢化物形成中的作用，并引入微观织构和晶界工程的概念，以提出改善氢脆的方法。基于所获得的结果，将开发一种新的氢化物脆化计算机模型，该模型可以模拟不同组织下的氢化物脆化过程。模拟的结果将允许确定最佳的微观结构，并可用于下一阶段的研究，以创新安大略省阿诺普赖尔的G.E-日立工厂的燃料芯块制造工艺

The signing of the Kyoto protocol and Sydney agreement by Canada will require considerable efforts to limit green house gas emission and therefore to rely on clean energy. Nuclear energy is considered, a clean energy of the future and new advanced CANDU reactors offer higher fuel burn-up, higher efficiency and excellent safety of operation. In addition Canada is engaged in design of the Generation IV reactors that are also considered for providing heat for production of clean fuel, hydrogen. Performance and high efficiency of these advanced reactors is linked to higher operating temperature and significant efforts have to be made to improve the performance and life expectancy of materials in high temperature environment. The present proposal is aiming to evaluate a role of microstructure in the hydrogen embrittlement of fuel cladding in order to improve life expectancy of fuel cladding tubes at higher operating temperatures. The proposed research targets improvement of processing and structure of Zircaloy-4 cladding to be used in advanced CANDU reactors and novel alloy, E110 (Zr-1Nb) for future application in the reactors of the IV generation. Novel experimental technique of orientation imaging, that was not yet applied in cladding embrittlement research, will allow us for the first time to examine a role of structure of grain boundaries in hydride formation and to introduce concepts of microtexture and grain boundary engineering to propose methods for improving hydrogen embrittlement. Based on the results obtained novel microstructural computer model of hydride embrittlement will be developed that will allow to simulate the process for different Zr alloys microstructures. The result of simulation will allow to define optimum microstructure and can be used in the next stage of research to innovate process of manufacturing fuel pellets in G.E-Hitachi plant in Arnprior (Ontario)