The  prediction  of  thermal  performance  in  wire  wrapped  assemblies,  such  as  fuel  pins  proposed  for  use  in  sodium-­cooled  nuclear  reactors,  is  vital  to  evaluate  overall  reactor performance  and  safety.  To  capture  the  performance  over  the  life  of  the  reactor,  these  simulations need to be performed not only for the original geometry of the pins, but for the  deformed  end-­of-­life  geometries.  The  Thermal/Hydraulic  Computational  Fluid  Dynamics (CFD) modeling required to reach these goals requires not only simulation of the complex geometry of hexagonal packed fuel assemblies with  helically  wire  wrapped  pins, but high-­fidelity turbulent flow modeling.  This can be achieved using the Nek5000 large-­eddy simulation code.   

To  ensure  that  these  simulations  can  be  used  to  make  operational  decisions,  this  allocation  supports  simulations  for  the  geometries  that  can  be  validated  against experiments.  Four geometries will be simulated: an isothermal undeformed duct with an undeformed  61-­pin  geometry,  an  isothermal  deformed  duct  with  a  deformed  61-­pin  geometry, a heated undeformed duct with an undeformed 61-­pin geometry, and a heated deformed  duct  with  an  undeformed  61-­pin  geometry.  These  results  will  be  compared  against  experiments  performed  at  Texas  A&M  and  Areva  Incoprorated’s  Richland  (WA) facility. The high-­fidelity data will be shared with the 25 European and American partners in the SESAME (Simulations and Experiments for the Safety Assessment of MEtal cooled reactors) project.