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的一个重要问题。尤其是高温水中材料的环境辅助裂解（EAC）的定量评估至关重要。但EAC受多种因素影响，目前估计还不够准确。这是一项将项目负责人的EAC基础研究成果与拥有丰富实用核反应堆数据的俄罗斯研究人员的研究成果相结合的合作研究。主要成果如下：(1)研究了腐蚀疲劳裂纹扩展速率与MnS夹杂物形态的关系。研究表明，夹杂物的尺寸分布比钢中的总硫含量更重要。东北大学对俄罗斯生产的反应堆压力容器钢硫含量高但MnS夹杂物分布均匀的小颗粒进行了评价。结果表明，仅根据硫含量预期的较高裂纹扩展速率并未观察到。(2)研究了小缺陷的检测方法。验证了使用相邻探针的感应电流聚焦电位降（ICFPD）技术和直流电位降（DCPD）技术的有效性。未来已经建立了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。这些材料将由中央结构材料研究所用俄语准备。评价将在东北大学进行。(3)研究了表面膜的老化退化与EAC之间的关系。交流了接触电阻等伴随薄膜生长的电学特性的研究成果。根据辐照过程中薄膜生长的电性能变化，明确了辐照辅助应力腐蚀开裂的关系。(4)针对VVER型核电站EAC事故进行了改进研究，并建立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评估的建议。(5)对低压缝式水轮机凝结桶的EAC进行了研究。提出了有关实验设施和分析的实用计划。已经明确的是，开尔文探针可用于评估薄水层条件下的腐蚀。实验已部分进行。较少的

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