Microstructural Characterization of RPV Materials Irradiated to High Fluences at High Flux
Microstructural Characterization of RPV Materials Irradiated to High Fluences at High Flux
复制标题
高通量辐照下 RPV 材料的微观结构表征
DOI：
10.1520/jai102128
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
H. Matsuzawa
中科院分区：
文献类型：
--
作者：
N. Soneda;K. Dohi;K. Nishida;A. Nomoto;M. Tomimatsu;H. Matsuzawa
了解反应堆压力容器钢在高通量区的脆化对核电站的长期运行具有重要意义。在本研究中，在日本的高压热冲击和核电站完整性管理项目中，对RPV钢进行了广泛的显微组织分析，辐照强度超过1020n/cm2， ebbb10 - 1mevat高通量。三维原子探针分析表征了这些材料中溶质原子团簇的形成。分析了通量、通量和化学成分对聚簇特性的影响。在透射电镜分析中发现了高、低Cu钢的位错环的形成，并研究了位错环的大小和数目密度随影响的变化。通过表面分析和晶界化学分析研究了磷在晶界上的偏析。我们发现晶界断裂引起的非硬化脆化不是这些材料和辐照条件下脆化的主要原因。研究了显微组织变化与夏比转变温度变化的关系。溶质原子团簇的体积分数与转变温度的变化有很好的相关性。用Orowan模型计算了位错环对相变温度变化的贡献，结果表明，在低Cu材料中，位错环可能是相变温度变化的主要贡献者，但在含Cu材料中，位错环的贡献较弱。溶质原子团簇和位错环贡献的平方根似乎是一个合理的模型来描述总量ΔRTNDT。
Understanding the embrittlement of reactor pressure vessel (RPV) steels at high fluence region is very important for the long term operation of nuclear power plants. In this study, extensive microstructural analyses were performed on the RPV steels irradiated to very high fluences beyond 1020n/cm2, E>1 MeVat high fluxes under the Pressurized Thermal Shock and Nuclear Power Plant Integrity Management projects in Japan. Three dimensional atom probe analyses were performed to characterize the solute atom cluster formation in these materials. The effects of fluence, flux, and chemical compositions on the characteristics of clusters were analyzed. The formation of dislocation loops was identified in the transmission electron microscopy analyses of high and low Cu steels, and the changes in loop size and number density with fluence were studied. P segregation on grain boundaries was also studied by surface analyses as well as grain boundary chemical analyses. We found that nonhardening embrittlement due to grain boundary fracture is not a major contributor to the embrittlement in these materials and irradiation conditions. The correlation of the microstructural changes and the Charpy transition temperature shifts was studied. The volume fraction of solute atom clusters has an excellent correlation with the transition temperature shifts. The Orowan model calculations of the contributions of dislocation loops to the transition temperature shifts show that in low Cu materials, dislocation loops may be a major contributor, but in Cu containing materials its contribution is weak. Root-sum-square of the contributions of solute atom clusters and dislocation loops seems to be a reasonable model to describe the total ΔRTNDT.