2022 Fiscal Year Final Research Report
Investigation on the mechanism of SCC using long-term aged L-grade austenitic stainless steels
Project/Area Number |
20K05143
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 26040:Structural materials and functional materials-related
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Research Institution | Japan Atomic Energy Agency |
Principal Investigator |
Kondo Keietsu 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 原子力基礎工学研究センター, 研究副主幹 (50391321)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 応力腐食割れ / 低炭素オーステナイト系ステンレス鋼 / 炉内構造材 |
Outline of Final Research Achievements |
L-grade austenitic stainless steels (SSs) are widely used for core components in nuclear power plants. It has been confirmed in the preliminary experiment that the long-term thermal aging (LTA) treatment enhanced the stress corrosion cracking (SCC) initiation susceptibility of cold-worked (CW) 316L SS. The metallurgical examinations on this material were conducted to identify the SCC accelerating factors. The results of microstructural examination revealed that the LTA treatment induced the change in the dislocation microstructure, and brought the heterogeneous deformation under the stress applied condition. Furthermore, the enhancement of grain boundary internal oxidation in SCC testing was also confirmed on 316L SS with the LTA treatment. It was considered that the microstructural change by the LTA treatment cause the localization of strain and the deterioration of corrosion resistance around grain boundaries under synergistic effect of tensile stress and corrosive environment.
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Free Research Field |
原子力材料工学
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Academic Significance and Societal Importance of the Research Achievements |
軽水炉炉内構造材料である低炭素オーステナイト系ステンレス鋼の経年劣化・損傷機構について、長時間熱時効による材料変化が応力腐食割れ発生感受性を増加させる可能性を示唆した。
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