1. Universities Nuclear Technology Forum – University of Cambridge 18 th -20 th March 2009 CFD Analysis of Operating Reactor Systems and a Proposed “Generation IV” Designs by S. Rolfo & A. Keshmiri Colleagues: D.R. Laurence, M.A. Cotton and Y. Addad School of Mechanical, Aerospace & Civil Engineering (MACE) The University of Manchester Manchester, M60 1QD www.CFDtm.org

2. Summary  Fuel Pins in Current AGR reactors  Code_Saturne  A proposal for next generation IV reactors: Sodium Fast Reactor (SFR) fuel assembly  Conclusions

3. Fuel Elements in AGRs

4. Various Configurations 1)Multi-start 2)Transverse 3) Hoop 4) Smooth

5. 2-dimensional approach

6. Test Cases Square Rib Profile (SRP) Transverse Rib Profile (TRP) Multi-Start Rib Profile (MSRP) Turbulence models: 1) Chen & Kim LRN k-ε model 2) Wilcox LRN k-ω model 3) Lien & Durbin v 2 f model

7. STAR-CD Results: contours Streamwise velcity contour: LRN Chen & Kim k-ε model Relative Pressure contour: LRN Wilcox k-ω model

8. STAR-CD Results: Lien & Durbin v 2 f model

9. y/k=1 y/k=0.1 STAR-CD Results: Lien & Durbin v 2 f model

10. Code_Saturne Code developed by EdF and now open source downloadable from: www.code-saturne.org  Unstructured  Co-located, Finite Volume Formulation  Different turbulent models (both RANS and LES)  Incompressible or expandable flows with or without heat transfer  Different modules: radiative heat transfer, combustion, magneto- hydrodynamics, compressible flows, two-phase flows  Possible coupling with Code_Aster for structural analysis and with Syrthes for thermal analysis.  Parallel code coupling capabilities (awarded the Gold medal on HPCx) ‏  TWiki collaborative website with forum and developments: http://cfd.mace.manchester.ac.uk/twiki/bin/view/Saturne/WebHome

11. 11 SFR fuel assembly: Case presentation Flow parameters: P/D = 1.1 Re = 11000 (Bulk vel = 1 m/s) Working fluid liquid sodium  = 847 kg/m3 µ = 2.55 10 -4 Kg/m/s Pr = 5 10 -3

12. SFR test case

13. SFR test case: comparison k-  and R ij R ij (SSG) k- 

14. Conclusions  SFR fuel assembly  Preliminary RANS calculations shows a completely different flow field respect to rod bundle in smooth configuration (no wire).  k-  and Rij SSG models give very similar results from a qualitatively point of view, but very different quantitatively  Possible LES or Hybrid RANS/LES calculations  AGR  Three different rib profiles have been tested and they all showed similar profiles for velocity, temperature and pressure.  Lien & Durbin v 2 f model was proved to be the best model for this test case.