Intergranular cracking mechanism in baffle former bolt materials for PWR core internals

Toshio Yonezawa, Koji Arioka, Hiroshi Kanasaki, Koji Fujimoto, Kazuhide Ajiki, Takanori Matsuoka, Sigeru Urata, Hitoshi Mizuta

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)

    Abstract

    In this study, the cause of intergranular cracking in baffle former bolts (BFBs) was estimated from metallurgical and chemical viewpoints based upon the experimental data and information published by EdF. At first, five kinds of possibilities were estimated as the cause of intergranular cracking in BFBs. Five possibilities estimated were (1) mechanical cracking caused by high strain in irradiation hardened austenitic stainless steels, (2) O2 SCC due to residual oxygen in the bolt stagnant region, (3) caustic SCC due to dry and wet phenomenon, (4) low pH SCC due to oxygen concentration cell, and (5) PWSCC due to radiation induced segregation. In this study each possibility was evaluated by the calculation and some out of pile tests. And also, the cause of the intergranular cracking in BFBs was estimated by the data of the post-irradiation examinations and basic out of pile tests for Type 316CW and Type 347 stainless steels in the authors' previous study. From these evaluation, the intergranular cracking in BFBs seems to be caused by the PWSCC, but not caused by mechanical cracking O2 SCC, caustic SCC or low pH SCC.

    Original languageEnglish
    Pages (from-to)212-217
    Number of pages6
    JournalNippon Genshiryoku Gakkaishi/Journal of the Atomic Energy Society of Japan
    Volume42
    Issue number3
    DOIs
    Publication statusPublished - 2000

    Keywords

    • Carbides
    • Core internals
    • Grain boundaries
    • IASCC
    • PWR type reactors
    • PWSCC
    • Stainless steels
    • Stress corrosion cracking
    • pH value

    ASJC Scopus subject areas

    • Nuclear Energy and Engineering

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