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

• 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
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044117/
• 关键词: Environmentally Assisted Cracking; Structural materials of Nuclear Reactor; Crack Growth; Nondestructive inspection; Micro Sampling; Water Chemistry; Slip-dissolution Model; き裂先端ひずみ速度; 表面酸化皮膜; 電流密度減衰曲線

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

确保核电站的安全是全世界面临的一个重要问题。尤其是材料在高温水中的环境辅助开裂(EAC)的定量评价是至关重要的。然而，EAC受诸多因素的影响，到目前为止估计还不够准确，这是一项合作研究，将项目负责人关于EAC的基础研究成果与拥有丰富实际核反应堆数据的俄罗斯研究人员的研究成果结合起来。主要研究成果如下：(1)研究了腐蚀疲劳裂纹扩展速率与MnS夹杂物形态的关系。结果表明，夹杂物的尺寸分布比钢中总硫含量更重要。东北大学对硫含量高，但MnS夹杂物细小颗粒分布均匀的俄罗斯产反应堆压力容器钢进行了评定。结果显示，…此外，仅从硫含量上没有观察到预期的更高的裂纹扩展速率。(2)研究了小缺陷的检测方法。验证了感应电流聚焦电位降(ICFPD)技术和相邻探头直流电位降(DCPD)技术的有效性。一个关于如何从外表面检测不锈钢焊缝内部缺陷的合作研究项目已经为未来设立了。这些材料将由中央结构材料研究所用俄语准备。在东北大学进行评估。(3)研究了表面膜老化降解与EAC的关系。交流了薄膜生长过程中接触电阻等电性能的研究结果。根据辐照过程中电学性质随薄膜生长的变化，进一步明确了辐照辅助应力腐蚀开裂的关系。(4)对VVER型核电站EAC事故的改进进行了研究，并提出了强有力的材料试验方法。提出了缺陷检测和裂纹扩展速率的评价方法。(5)对低压水轮机凝结水桶的内燃机进行了研究。提出了一套切实可行的实验装置和分析方案。研究表明，开尔文探头在评价薄水层条件下的腐蚀性能方面是有用的。已经进行了部分实验。较少

项目成果

B.T.Timofeev,G.P.Karzov,A.A.Gorbakony,Yu.K.Nikolaev: "Corrosion and Mechanical Strength of Welded Joints of Downcomers for RBMK Reactors"The Seventh Meeting of Joint Research Programme between RIFT Tohoku University and CRISM<<Prometey>>within JAPAN-RUSSI

B.T.Timofeev、G.P.Karzov、A.A.Gorbakony、Yu.K.Nikolaev：“RBMK反应堆降液管焊接接头的腐蚀和机械强度”RIFT东北大学与日本CRISM《Prometey》联合研究项目第七次会议-

Y.Lee: "Study on Corrosion Fatigue Crack Tip Solution Chemistry of 15X2MFASteels in BWR and PWR Environments" Proceedings of International Workshop on Environmentally Assisted Cracking in Nuclear Power Plants,Oct.2,1998,Sendai. 23-27 (1998)

Y.Lee：“Study on Corrosion Fatigue Crack Tip Solution Chemistry of 15X2MFASteels in BWR and PWR Environmental”，核电站环境辅助裂化国际研讨会论文集，1998年10月2日，仙台。

T.Shoji,K.S.Raja,G.F.Li,Y.J.Lee and Anna Brozova: "Critical parameters of environmentally assisted cracking in nuclear systems"Proceedings of Corrosion/2000, NACE's Annual Conference, 26-31 March 2000, Orlando, Florida, USA, T-2A. (in press).

T.Shoji、K.S.Raja、G.F.Li、Y.J.Lee 和 Anna Brozova：“核系统环境辅助裂化的关键参数”Proceedings of Corrosion/2000，NACE 年会，2000 年 3 月 26-31 日，美国佛罗里达州奥兰多，T

李 倫柱: "高温高圧水中における軽水炉圧力容器用鋼の環境助長割れ内部環境の計測に関する研究" 材料と環境. 47,12. 783-788 (1998)

李论举：“轻水堆压力容器钢在高温高压水下环境促裂内部环境的测量研究”材料与环境47，12（1998）。

Y.Lee: "Quantitative Analysis of Environmentally Assisted Crack Tip Chemistry of Reactor Pressure Vessel Steel in High Temperature Water"Proceedings of Eurocorr'98-The European Corrosion Congress,Sept.28-Oct.1,(1998),Utrecht,The Netherlands. CD-ROM (1999)

Y.Lee：“高温水中反应堆压力容器钢的环境辅助裂纹尖端化学的定量分析”Eurocorr98-欧洲腐蚀大会论文集，9月28日至10月1日，（1998年），荷兰乌得勒支