1 Parametric Thermal-Hydraulic Analysis of TBM Primary Helium Loop Greg Sviatoslavsky Fusion Technology Institute, University of Wisconsin, Madison, WI With contributions from C.P.C. Wong, General Atomics, M. Dagher, S. Smolentsev, UCLA, S. Malang, Consultant, Germany ITER US TBM Meeting UCLA MAY 10, 2006

2 Presentation Outline  Primary helium loop description  First Wall thermal analysis  TBM pressure drop  Results summary  Future work & consideration

3 He Circuit 1 He Circuit 2 Primary Helium Loop Back Plate First Wall Top Plate Bottom Plate Divider Plate Grid Plates

4 First Wall Analysis Approach D-T Transient Thermal Conditions Helium Inlet & Outlet Temperature Parametric Analysis FW Channel Layout FW Temperature Limits Require Heat Transfer Coefficient (h) Require Helium Flow Rate Channel Dimensions & Roughening Max FW Temperature FW Pressure Drop Parametric Analysis

5 0.3 MW/m 2 flux over 90% & 0.5 MW flux over 10% FW Nuclear heating based on scaling prior neutronic results 520 o C maximum FW temperature at 2 mm depth 550 o C maximum FW surface temperature First Wall Analysis Input Parameters 300 o C helium TBM inlet temperature 390 o C helium TBM outlet temperature 20 mm x 19.6 mm channel cross-section dimensions Uniform sand-grain roughness Seven pass circuit layout (5 channels per pass)

kg/s required helium flow rate 4813 W/m 2 -K heat transfer coefficient 378 o C FW helium exit temperature 523 o C maximum FW temperature at 2 mm depth 556 o C maximum FW surface temperature First Wall Thermal Analysis Results

7 Circuit 2 Total P-drop MPa TBM Pressure Drop Results First Wall MPa Top Plate MPa Bottom Plate MPa Divider Plate Grid Plates First Wall MPa MPa 0.01 MPa MPa Circuit 1 Total P-drop MPa

8 First Wall0.096 MPa Top/Bottom Plate0.001 MPa Divider Plate0.005 MPa Upper Grid Plates0.003 MPa Lower Grid Plates0.01 MPa TBM Pressure Drop Results First Wall Top Plate Bottom Plate Divider Plate Upper Grid Plate Lower Grid Plate

9 Downstream (hotter) FW flow requires higher h than upstream (cooler) flow Control velocity with number of channels per pass [h is f(velocity)] Initial analysis indicates pressure drop improves by 34% Alternate FW Channel Configuration Pass 1 Pass 2Pass 3 Fixed Flow Rate

10 Helium Thermal-Hydraulic Results Summary Operational PhaseD-T Operation Heat Flux (transient) 0.3 MW over 90% & 0.5 MW over 10% FW Configuration7 pass, 5 channels/pass Flow Rate - FW Velocity0.89 kg/s - 37 m/s TBM He inlet/outlet Temperature300 o C / 390 o C Wall RoughnessUniform sand-grain (FW) Pressure Drop0.107 MPa Max FW temperature 556 o C (surface) 526 o C 2mm)

11 Future Work & Consideration  Evaluate back plate design  Can we do without 2D roughening?  Determine maximum allowable pressure drop  Investigate alternate configurations  CFD analysis required to better account for FW counter flow and TBM flow distribution  Continue iteration with MHD analysis

12 Back-up Slides

13 Nuclear Heating Values First Wall W Top Plate 5253 W Bottom Plate 5253 W Divider Plate W Grid Plates W Side Walls W

14 Helium Properties Density6.1kg/m^3 Specific Heat5200j/kg-K Thermal Conductivity0.253W/m-k Viscosity3.50E-05kg/m-s