About this Abstract | 
  
   
    | Meeting | 
    2025 TMS Annual Meeting & Exhibition
       | 
  
   
    | Symposium 
       | 
    Elucidating Microstructural Evolution Under Extreme Environments
       | 
  
   
    | Presentation Title | 
    Real-Time Neutron Diffraction to Support Interpretation of DSC Results on Zr-2.5Nb for Reactor Pressure Tubes | 
  
   
    | Author(s) | 
    Sven C. Vogel, Amy I.  Fluke, Daniel J.  Savage, Toshiro  Tomida | 
  
   
    | On-Site Speaker (Planned) | 
    Sven C. Vogel | 
  
   
    | Abstract Scope | 
    
Under postulated accident scenarios dual-phase Zr-Nb cladding or pressure tube material with α (hcp) and β (bcc) phases may be subjected to high temperature transients up to 1200°C, resulting in heating rate-dependent α-β phase transformation. Since the thermophysical properties are affected by the phase changes, it is important to understand this behavior in order to predict the performance under extreme thermal transient conditions. A hysteresis in calorimetry measurements was observed between heating and cooling. Furthermore, as-manufactured tube material showed a small enthalpy change during first heating that did not appear on subsequent heating. Neutron diffraction with identical temperature profiles (heating rates of 5C/min and 20C/min) was performed on the HIPPO diffractometer to understand these observations. Phase fractions, lattice parameters and texture evolution were tracked with a 15 second time resolution for comparison with previous DSC data and modelling of phase transformation textures. | 
  
   
    | Proceedings Inclusion? | 
    Planned:  | 
  
 
    | Keywords | 
    Nuclear Materials, Phase Transformations, Characterization |