Failure of steam generators in pressurized water reactor (PWR) nuclear systems can lead to  expensive  plant  shut-­downs.    Flow-­induced  vibrations  in  the  steam  generators  was  identified  as  a  high  impact  problems  of  the  Department  of  Energy’s  Nuclear  Energy Modeling  and  Simulation  program  as  a  high-­impact  problem  for  nuclear  industry.  In  addition  to  the  impact  on  existing  nuclear  reactors,  there  is  a  growing  interest  in  small modular  reactors  (SMRs).  Many  of  the  proposed  SMR  designs,  from  vendors  such  as  NuScale, mPower, and Westinghouse, are based on an integral PWR concept. In all of these systems, flow-‐induced vibrations are an important limiting factor in the operation of heat exchangers and steam generators.

An  advanced  numerical  simulation  capability  for  modeling  such  phenomena  will  help  improve the analysis and evaluation of different design variants in terms of vibrations and heat  transfer  performance,  complementing  expensive  experimental  tests  and  reducing  their cost. Such a tool will have a broad utility for various nuclear technology applications, including other fluid-­structure interaction problems, such as fluid elastic instability for rod bundles  in  cross  flows.  This  tool  will  couple  Lawrence  Livermore’s  Diablo  structural  mechanics  code  with  Argonne’s  Nek5000  computational  fluid  dynamics  (CFD)  code. Because the structural displacements are small, a one-­way coupling, where the CFD results provide inputs to the structural code, can be used.

In collaboration with US-­based NuScale Power, the research team will simulate a series to perform  a  series  of  single  phase  turbulent  flows,  including  several  experimental  and  mockup  geometries  of  a  helical  coil  steam  generator.  These  will  be  compared  to,  and validated, using existing experiments at Texas A & M University.