A cooperative Study on Environmentally Assisted Cracking of structural materials of nuclear reactor

核反应堆结构材料环境辅助裂解合作研究

基本信息

批准号：
09044117
负责人：
SHOJI Tetsuo
金额：
$ 4.86万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Assuring the safety of nuclear power plants is an important issue all over the world. Especially the quantitative evaluation of environmentally assisted cracking (EAC) of materials in high temperature water is critical. However, EAC is affected by so many factors that estimation is not accurate enough up to now.This is a cooperative research that combines the fundamental research achievements on EAC of the leader of this project with the research results of Russian researchers who possess rich data of practical nuclear reactors. Main achievements can be summarized as follows :(1) The relation between corrosion fatigue crack growth rate and the shape of MnS inclusions has been studied. It has been shown that the size distribution of the inclusions is more important than the total sulfur content in steel. Reactor pressure vessel steel made by Russian that has high sulfur content but well distributed small particles of MnS inclusions was evaluated in Tohoku University. Results showed that … More the higher crack growth rate expected only from the sulfur content was not observed.(2) Detection method for small defects have been studied. The validities of induced current focusing potential drop (ICFPD) technique and direct current potential drop (DCPD) technique using adjacent probes were confirmed. A cooperative research project on how to detect inside defects in stainless steel welds from the outer surface has been set up for the future. The materials will be prepared by Central Institute of Structural Materials in Russian. The evaluation will be done in Tohoku University.(3) The relation between aging degradation of surface film and EAC has been studied. The research results on contact electric resistance and other electric properties accompanying film growth were exchanged. According to the electric property change with film growth during irradiation, the relation to irradiation assisted stress corrosion cracking has been made clearer.(4) Investigation for improvement for EAC incidents of VVER type nuclear power plants and, strong methods of material test has been done. Defect detection and crack growth rate evaluation have been suggested.(5) EAC at condensation pail of low pressure seam turbine has been researched. A practical plan about experimental facilities and analysis has been suggested. It has been made clear that Kelvin probe is useful for evaluating corrosion in the thin water layer condition. The experiments have been carried out partly. Less

确保核电厂的安全是世界各地的重要问题。特别是对高温水中材料的环境辅助裂纹（EAC）的定量评估至关重要。但是，EAC受到许多因素的影响，以至于估计到现在还不够准确。这是一项教练研究，结合了该项目领导者EAC的基本研究成就与拥有实用核反应堆的丰富数据的俄罗斯研究人员的研究结果。主要成就可以总结如下：（1）已经研究了腐蚀疲劳裂纹生长速率与MNS夹杂物的形状之间的关系。已经表明，夹杂物的尺寸分布比钢中的总硫含量更重要。俄罗斯制造的反应堆压力容器钢在Tohoku University评估了硫磺含量高但分布良好的MN夹杂物的小颗粒。结果表明，仅观察到仅观察到硫含量的较高裂纹生长速率。（2）已经研究了小缺陷的检测方法。确认了使用相邻问题的当前聚焦电位下降（ICFPD）技术和直流电位下降（DCPD）技术的有效性。关于如何在外表面的不锈钢焊缝中检测内部缺陷的教练研究项目已为未来建立。这些材料将由中央结构材料研究所在俄罗斯准备。评估将在Tohoku University进行。（3）表面膜的衰老降解与EAC之间的关系已经研究了。交换了有关接触电阻和其他涉及膜增长的电力性能的研究结果。根据辐照过程中膜增长的电特性变化，与辐照辅助应力腐蚀破裂的关系变得更加清晰。（4）研究改善了VVER型核电站的EAC事件的研究，并且已经进行了强大的材料测试方法。已经提出了缺陷检测和裂纹生长速率评估。（5）已经研究了低压接缝涡轮机的冷凝垫。已经提出了有关实验设施和分析的实用计划。已经明确表明，开尔文探针对于评估在薄水层条件下的腐蚀很有用。实验部分进行了。较少的