Predicting the flow stress of zircaloy-4 under in-reactor accident conditions

Chi Toan Nguyen, Javier E. Romero, Antoine Ambard, Michael Preuss, João Quinta Da Fonseca

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

2 Citations (Scopus)


During loss-of-coolant accident (LOCA) and reactivity-initiated accident (RIA), nuclear fuel rods experience high heating rates that change the microstructure and properties of zirconium cladding materials. We sought to determine how different fast heating rates affect the kinetics of transformation and whether their consequences on the material yield stresses in the dual-phase region could be predicted. Phase fraction and texture of cold-rolled Zircaloy-4 were thus measured at fast heating rates similar to those experienced during LOCA and RIA by in situ high-energy synchrotron X-ray diffraction; the yield stress was also measured at different heating rates to the same dual-phase temperature by the electrical resistance method. A crystal plasticity finite-element model was used to simulate the flow stresses with the inputs of the measured phase fraction and texture. The model was calibrated using the flow stress at the heating rate of 10°C s-1 and used to predict the flow stress at the heating rate of 50°C s-1 at the same temperature. A significant shift of the p transus temperature was identified for fast heating rates in the range of 10 to 100°C s-1. There was great similarity in texture at different heating rates. In the dual-phase temperature region, the α texture was almost identical to the starting texture, and the p texture was nearly random. Yield stresses of cold-rolled Zircaloy-4 decreased at a faster heating rate at the same temperature of 920°C. A good agreement was found between the experimental and predicted flow stress at different heating rates, indicating this methodology can potentially be used to predict flow behavior in a fast transient regime.

Original languageEnglish
Title of host publicationZirconium in the Nuclear Industry
Subtitle of host publication18th International Symposium
EditorsRobert J. Comstock, Arthur T. Motta
PublisherASTM International
Number of pages26
ISBN (Electronic)9780803176416
Publication statusPublished - 2018
Externally publishedYes
EventInternational Symposium on Zirconium in the Nuclear Industry 2016 - Hilton Head, United States of America
Duration: 15 May 201619 May 2016
Conference number: 18th

Publication series

NameASTM Special Technical Publication
VolumeSTP 1597
ISSN (Print)0066-0558


ConferenceInternational Symposium on Zirconium in the Nuclear Industry 2016
Country/TerritoryUnited States of America
CityHilton Head
Internet address


  • Crystal plasticity
  • Kinetics of phase transformation
  • Loss-of-coolant accident
  • Reactivity-initiated accident
  • Synchrotron X-ray diffraction
  • Yield stress
  • Zircaloy-4

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