In-Core SCC Growth Behavior of Type 304 Stainless Steel in BWR Simulated High-Temperature Water at JMTR

• Published in: Journal of nuclear science and technology 2008-08, Vol.45 (8), p.725-734
• Main Authors: KAJI, Yoshiyuki, UGACHI, Hirokazu, TSUKADA, Takashi, NAKANO, Junichi, MATSUI, Yoshinori, KAWAMATA, Kazuo, SHIBATA, Akira, OHMI, Masao, NAGATA, Nobuaki, DOZAKI, Koji, TAKIGUCHI, Hideki
• Format: Article
• Language: English
• Subjects: Austenitic stainless steels; Boiling water reactors; Gamma radiation; Gamma rays; Simulation; Stainless steels; Stress corrosion cracking; Stresses
• ISSN: 0022-3131; 1881-1248
• DOI: 10.3327/jnst.45.725

Irradiation-assisted stress corrosion cracking (IASCC) is one of the critical concerns when stainless steel components have been in service in light water reactors for a long period. In-core IASCC growth tests have been carried out using the compact tension-type specimens of type 304 stainless steel that had been pre-irradiated up to a neutron fluence level around 1×1025 n/m2 under a pure water simulated boiling water reactor (BWR) coolant condition at the Japan Materials Testing Reactor (JMTR). In order to investigate the effect of synergy of neutron/gamma radiation and stress/water environment on SCC growth rate, we performed ex-core IASCC tests on irradiated specimens at several dissolved oxygen contents under the same electrochemical potential condition. In this paper, results of the in-core SCC growth tests are discussed and compared with the results obtained by ex-core tests from a viewpoint of the synergistic effects on IASCC. From results of in-core and ex-core tests using pre-irradiated specimens, the effect of synergy of neutron/gamma radiation and stress/water environment on SCC growth rate was considered to be small, because the in-core data under the same ECP condition were similar to the ex-core data under the DO=32 ppm condition.