Cr涂层Zr-4合金的研制及其辐照与腐蚀行为研究

Zirconium alloy fuel cladding with surface coating is one of the best ways to prevent zirconium-water reaction and improve the safety of nuclear reactor. In order to deeply understand the evolution behaviors and mechanism of the microstructure, properties and performance of the Zr-4 alloy with surface Cr coating in the irradiation and corrosive environments simulated nuclear reactors, and to provide the experimental data and theoretical foundation for large-scale industrial application in the future, Zr-4 alloys with surface Cr coating were prepared by electroplating method in this project. The coated samples were irradiated by H+, He+ and Cr+ ions, and then corroded. The optimal preparation parameters during the electroplating process for Cr coating Zr-4 alloy were confirmed to prepare the samples with excellent comprehensive properties. The thermodynamics, kinetics and related mechanism of the growth of Cr coatings with excellent interface microstructure characteristics, great interface thermal properties and binding force were investigated. The evolution behaviors and laws of the microstructure and properties of the Cr coatings and interfaces under the synergistic effects of displacement damage, hydrogen and helium as well as the simulated conditions of corrosion solution with high temperature and high pressure in first circuit of LWR and the steam environment with high temperature in LOCA nuclear accident were studied in detail and explained scientifically. The internal relationships between Cr coating structure and the properties (irradiation, corrosion, interface thermophysical properties and binding force, etc.) of Zr-4 alloys with surface Cr coating were provided, and the corresponding mathematical and theoretical models were established.

涂层锆合金燃料包壳是防止锆水反应和提高核反应堆安全性的最佳方案之一。为了在堆外更准确的理解Cr涂层Zr-4合金在辐照、腐蚀环境中的微观结构与性能的演化行为与机制，以及为将来大规模工业化应用提供实验依据和奠定基础。本项目采用电镀方法制备Cr涂层Zr-4合金，采用H+、He+和Cr+离子对其进行辐照，并测试腐蚀性能。拟初步探明在Zr-4合金表面制备Cr涂层的较佳电镀工艺参数，研制出综合性能优越的样品。揭示具有优异界面微观结构特征、良好界面热物理性能和结合力的Cr涂层生长的热力学与动力学，以及相关机制。深入研究Cr涂层及界面在位移损伤与氢、氦协同作用下，以及模拟的LWR一回路高温高压腐蚀溶液和LOCA核事故高温蒸汽环境中的微观结构与性能的演化行为与规律，探索最基础问题和现象的科学解释。揭示可调控Cr涂层结构与合金性质(辐照、腐蚀、界面热物理性能与结合力等)之间的内在联系，并建立相应的数、理模型。

铬涂层锆合金燃料包壳是防止锆水反应和提高核反应堆安全性的最佳方案之一。针对目前现有技术制备铬涂层锆合金的不足，本项目首次在国内外采用电镀技术制备出了综合性能优异的铬涂层锆合金样品，获得了能在锆合金表面制备出优异铬涂层的电沉积工艺参数。在充分获得了涂层与锆基体的界面微观结构特征和界面强度等性质与性能基础之上，研究了电镀工艺参数(镀液配方、PH值、温度、电流密度、电镀时间等)对铬涂层锆合金的性能影响，建立了电镀工艺参数与涂层微观结构参量之间的内在关系；研究了电镀过程中铬涂层在锆合金表面生长的热力学与动力学。通过综合分析与讨论各种实验条件下的现象与结果，实现了涂层结构的可控生。对比分析了本项目制备的铬涂层锆合金、商用锆合金、磁控溅射技术制备的铬涂层锆合金在高温高压腐蚀和高温蒸汽腐蚀结果，可以得知本项目制备的铬涂层锆合金的腐蚀性能最优。采用氦单束、氪+氢+氦三束离子对铬涂层锆合金样品进行了原位离子辐照实验和辐照后的原位退火实验，对辐照缺陷进行了特征参量的统计，建立了辐照剂量/退火时间与辐照缺陷特征参量之间的内在关系。研究了辐照缺陷在辐照过程和退火过程中的演化行为与机制，以及物质在界面处迁移、聚集和生长的基本科学问题等。本项目授权国家发明专利1件，发表了2篇关于电镀铬涂层锆合金的研究论文，均为第一致谢；项目经费还支持发表了其他相关论文33篇。项目经费支持了7名硕士和4名博士毕业，其中1篇硕士学位论文是关于电镀铬涂层锆合金研究论文。同时还培养了2位博士生和2位硕士生，其中1位硕士生将来的硕士学位论文将以铬涂层锆合金的研究为论文。6人次参加了核行业的国内主流会议。本项目的研究将为实现Cr涂层锆合金燃料包壳的大规模工业化生产提供实验依据和理论基础。