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Crack Growth Rate and Fracture Toughness of CF3 Cast Stainless Steels at ~3 DPA

  • Y. Chen
  • W.-Y. Chen
  • B. Alexandreanu
  • K. Natesan
  • A. S. Rao
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

Cast austenitic stainless steels (CASS) used in reactor core internals are subject to high-temperature coolant and energetic neutron irradiation during power operations. Due to both thermal aging and irradiation embrittlement, the long-term performance of CASS materials is of concern. To assess the cracking behavior of irradiated CASS alloys, crack growth rate (CGR) and fracture toughness J-R curve tests were performed on two CF3 alloys. Miniature compact tension specimens were irradiated to ~3 dpa, and were tested at ~315 °C in simulated LWR coolant environments with low corrosion potentials. No elevated cracking susceptibility was observed at this dose in the test environments. The power exponents of the 3 dpa J-R curves were much lower than that of unirradiated or irradiated specimens at lower doses, indicating a significant decline in fracture resistance. A preliminary microstructural study revealed irradiation-induced microstructural changes in both austenite and ferrite, suggesting an embrittlement mechanism involving both phases at this dose level.

Keywords

Cast austenitic stainless steels Neutron irradiation Stress corrosion cracking Thermal aging Irradiation embrittlement Microstructural characterizations 

Notes

Acknowledgements

The authors would like to thank Ms. T. M. Karlsen, OECD Halden Reactor Project, Halden, for her help with the irradiation experiment and specimen transfer. Chi Xu and Loren Knoblich are acknowledged for their contributions to the experimental effort. The TEM work was performed at the IVEM-Tandem Facility funded by the US Department of Energy Office of Nuclear Energy. This work is sponsored by the U.S. Nuclear Regulatory Commission, under Project V6380, and by the U.S. Department of Energy, under contract # DE-AC02-06CH11357.

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Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Y. Chen
    • 1
  • W.-Y. Chen
    • 1
  • B. Alexandreanu
    • 1
  • K. Natesan
    • 1
  • A. S. Rao
    • 2
  1. 1.Argonne National LaboratoryDarienUSA
  2. 2.US Nuclear Regulatory CommissionRockvilleUSA

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