Study on SCC growth behavior of BWR core shroud

S. Ooki, Y. Tanaka, K. Takamori, S. Suzuki, S. Tanaka, Y. Saito, T. Nakamura, T. Kato, K. Chatani, M. Kodama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

38 Citations (Scopus)

Abstract

Recent studies suggest that material hardening should cause enhancement in Stress Corrosion Cracking (SCC) growth rate of Stainless Steels (SS). While the hardening of BWR core shroud of high fluence is governed mainly by neutron irradiation, the hardening of HAZ of BWR core shroud of low fluence is dominated by welding condition. Therefore, in this study, SCC growth rates of SS irradiated up to the middle of 1024 n/m2 and un-irradiated SS were measured in order to obtain reasonable estimation for SCC growth behavior in the core shrouds. The SCC growth rates of actual BWR core shrouds made of 304 SS were measured using 1T-CT specimens in BWR simulated environment. The cumulative neutron fluences of the specimens were 1.5-5.1×10 24 n/m2. The stress intensity factor, K-value for the SCC growth tests were from 10.5 to 24.2MPa m0.5. The test results showed that the SCC growth rates of the specimen from actual core shrouds were enveloped by the current upper limit, 9.2×10-10 m/s of the K-da/dt disposition curve of JSME NA1-2002 standard for Sensitized 304 SS in NWC Reactor Water, suggesting that the limit is reasonably applicable even for SS irradiated up to those fluences. The SCC growth rates of the BWR shroud mock-ups made of 316L SS, taking the welding procedures simulating actual components, were also measured using 1/2T-CT specimens from HAZ. In spite of substantial hardness of HAZ, 200 HV, all SCC growth rates from the specimens were below the K-da/dt disposition curve of the JSME NA1-2002 standard for Low Carbon Austenitic SS in NWC Reactor Water. This fact suggests that the degree of hardening assumed in actual shrouds' HAZ should bring little enhancement effect in SCC growth rates.

Original languageEnglish
Title of host publicationProceedings of the Twelfth International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors
Pages365-376
Number of pages12
Publication statusPublished - 2005 Dec 1
Externally publishedYes
Event12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors - Salt Lake City, UT, United States
Duration: 2005 Aug 142005 Aug 18

Publication series

NameProceedings of the Twelfth International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors

Other

Other12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors
CountryUnited States
CitySalt Lake City, UT
Period05/8/1405/8/18

Keywords

  • Core shroud
  • Crack Growth Rate
  • IASCC

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Ooki, S., Tanaka, Y., Takamori, K., Suzuki, S., Tanaka, S., Saito, Y., Nakamura, T., Kato, T., Chatani, K., & Kodama, M. (2005). Study on SCC growth behavior of BWR core shroud. In Proceedings of the Twelfth International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors (pp. 365-376). (Proceedings of the Twelfth International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors).