TerraPower HT9 Mechanical and Thermal Creep Properties

  • Cheng XuEmail author
  • Micah Hackett
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


TerraPower has revitalized the manufacturing of HT9, and optimized its heat treatment to be used as fuel claddings in the Traveling Wave Reactor. TerraPower initiated a comprehensive test program to compare the mechanical and thermal creep properties of the optimized TerraPower HT9 to the historical HT9. The uniaxial tensile tests show TerraPower HT9 has improved yield strength compared to historical HT9 across all temperatures. Charpy impact toughness tests on TerraPower HT9 show lower upper shelf energy compared to historical HT9, but the ductile to brittle transition temperature (DBTT) between the steels remain similar. Three point bend tests between room temperature and 400 °C show comparable fracture toughness to those of historical HT9. Thermal creep test data suggest TerraPower HT9 have improved creep strength compared to historical HT9.


Fracture Toughness Ultimate Tensile Strength Creep Rate Impact Toughness Charpy Impact 
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  1. 1.
    R. Klueh, J. Vitek, Tensile behavior of irradiated 12Cr-1MoVW steel. J. Nucl. Mater. 137, 44 (1985)CrossRefGoogle Scholar
  2. 2.
    R. Klueh, A. Nelson, Ferritic/martensitic steels for next-generation reactors. J. Nucl. Mater. 371, 37–52 (2007)CrossRefGoogle Scholar
  3. 3.
    Sandvik, Impact strength of Sandvik HT9 (Sandvik, Stockholm, 1980)Google Scholar
  4. 4.
    J.-H. Baek, T.S. Byun, S.A. Maloy, M.B. Toloczko, Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique. J. Nucl. Mater. 444, 206–213 (2014)CrossRefGoogle Scholar
  5. 5.
    B. Chin, An analysis of the creep properties of a 12Cr-1Mo-W-V steel, in Topical Conference on Ferritic Alloys for Use in Nuclear Energies Technologies, 1984Google Scholar
  6. 6.
    Sandvik, HT-9 datasheet 1, 750ENG (Sandvik, 1981)Google Scholar
  7. 7.
    M. Toloczko, F. Garner, C. Eiholzer, Irradiation creep and swelling of the U.S. fusion heats of HT9 and 9Cr-1Mo to 208dpa at ~400°C, in Sixth International Conference on Fusion Materials, 1993Google Scholar
  8. 8.
    T. Byun, S. Maloy, J.H.Yoon, Small specimen reuse technique to evaluate fracture toughness of high dose HT9 steel (ASTM Special Publications, 2015)Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2017

Authors and Affiliations

  1. 1.TerraPowerBellevueUSA

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