1. P ROGRESS ON THE O VERALL P OWER C ORE C ONFIGURATION OF THE ARIES-ACT X.R. Wang 1, M. S. Tillack 1, S. Malang 2 1 University of California, San Diego, CA 2 Fusion Nuclear Technology Consulting, Germany ARIES-Pathways Project Meeting Gaithersburg, MD October 13-14, 2011

2. R EVIEW OF THE D ESIGN F EATURES OF THE ARIES-AT P OWER C ORE  All the components including the inboard blanket and shield, outboard blanket and shield and divertor are cooled by LM LiPb.  The inboard blanket, outboard blanket, upper and lower divertor modules are integrated with the HT shield (structural ring) into one replaceable unit, and the unit is attached to the bottom structure of the VV.  All the connections/disconnections between coolant access pipes and individual component are located the outside of the outboard HT shield where the He- generation should be low enough to allow for re- welding.  All LM access pipes should be designed as concentric tubes with the cold inlet flow (~650 ᵒ C) in the annulus, cooling in this way the inner tube (1100 ᵒ C) to the allowable temperature (~1000 ᵒ C) of the SiC/SiC.

3. One sector (22.5 degree) ARIES-ACT (Aggressive Physics) R=5.5 m A=1.375 m Elongation=2.2 ARIES-ACT (Aggressive Physics) R=5.5 m A=1.375 m Elongation=2.2 Plasma OB divertor plate IB divertor plate Dom plate IB FW OB FW Results of CAD analysis: Total plasma surface area=~475 m 2 Total plasma volume=~417 m 3 Total FW surface area=~452 m 2 (A IB =140 m 2,A OB =312 m 2 ) Total Divertor surface area=~143 m 2 Results of CAD analysis: Total plasma surface area=~475 m 2 Total plasma volume=~417 m 3 Total FW surface area=~452 m 2 (A IB =140 m 2,A OB =312 m 2 ) Total Divertor surface area=~143 m 2 Geometry Definitions of the FW and divertor plates (from Chuck):  Thickness of SOL at mid-plane=10 cm  Curved FW  OB divertor location=R-a/2  IB divertor location=R-a Geometry Definitions of the ACT FW and Divertor Plate Are Based on the ACT-1B Strawman

4. T WO P OSSIBLE D ESIGN O PTIONS FOR THE ACT-1 P OWER C ORE C ONFIGURATION Design Option #1Design Option #2 IB BlanketPb 83 Li 17 cooled SiC/SiC structure IB HT ShieldPb 83 Li 17 cooled steel and SiC/SiC tube Helium-cooled steel structure and ODS tube 1 st OB BlanketPb 83 Li 17 cooled SiC/SiC structure 2 nd OB BlanketPb 83 Li 17 cooled SiC/SiC structure OB HT ShieldPb 83 Li 17 cooled steel and SiC/SiC tube Helium-cooled steel structure and ODS tube Upper/Lower Divertors Helium-cooled W- based divertor

5. P OWER C ORE C ONFIGURATION FOR THE D ESIGN O PTION #1 (L I P B - COOLED HT S HIELD ) Thickness radius Inboard: Vacuum vessel: 0.4 m HT shield: 0.24 m IB blanket: 0.35 m Outboard: 1 st Blanket: 0.30 m 2 nd Blanket: 0.45 m HT shield: 0.15 m Vacuum vessel: 0.25 m Vertical build: W divertor target: ~0.07 m (He, ODS steel and W) Replaceable HT shield: 0.30 m (He, FS and ODS steel) HT shield: 0.3 m (SiC, FS and LiPb, ODS, He) (0.15 m, 15% SiC, 10% LiPb, 75% FS for ARIES-AT) Vacuum vessel: 0.4 m Composition: the same as the ARIES-AT  One of the He-cooled W-based divertor concepts would be integrated into the power core.

6. I NTEGRATION OF THE H E - COOLED W- BASED D IVERTOR IN THE ACT P OWER C ORE  Fingers arranged over the entire plate  Imping-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~14 MW/m 2  Avoiding joints between W and ODS steel at the high heat flux region  ~550,000 units for a power plant  Fingers arranged over the entire plate  Imping-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~14 MW/m 2  Avoiding joints between W and ODS steel at the high heat flux region  ~550,000 units for a power plant  T-Tube divertor: ~1.5 cm dia. X 10 cm long  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~11 MW/m 2  ~110,000 units for a power plant  T-Tube divertor: ~1.5 cm dia. X 10 cm long  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~11 MW/m 2  ~110,000 units for a power plant  Plate divertor: 20 cm x 100 cm  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~9 MW/m 2  ~750 units for a power plant  Plate divertor: 20 cm x 100 cm  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~9 MW/m 2  ~750 units for a power plant  Two zone divertor (any combination of the plate and finger and T-tube)  Fingers for q>~8 MW/m 2, plate for q<~8 MW/m 2  Decreased number of finger units  Two zone divertor (any combination of the plate and finger and T-tube)  Fingers for q>~8 MW/m 2, plate for q<~8 MW/m 2  Decreased number of finger units  One of the divertor concepts to be integrated in the ACT power core.  The selection of the divertor depends on the peak heat flux and heat flux profile of the ACT- 1.  Tubular or T-Tube He-cooled SiC/SiC divertor  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~5 MW/m 2  Tubular or T-Tube He-cooled SiC/SiC divertor  Impinging-jet cooling, T in /T exit =700/800 ᵒC  Allowable heat flux up to~5 MW/m 2 W-based divertor OB divertor plate W-Ta-ODS joints

7. The Modified W-Ta-ODS Joints Indicated Simpler Fabrication and Smaller Strains The original design The modified design  Avoided ratcheting  Reduced plastic strains in the ODS and Ta rings  Simpler design and simpler fabrication steps  Avoided singularities  Added braze layer in the joints for analysis  Assumed the material properties of the Cu to simulate the braze material, because we lacked alloy composition and properties for real brazes  ~11,000, 000 non-linear structural nodes ODS TaW ODS Ta W Explosive weldedDiffusion welded TIG or Laser Brazed *Dara Navaei, Master’s thesis (draft), “Elastic-plastic analysis of the transition joint for a high performance divertor target plate” Pure Ta, ε allow =~15% at RT and 5% at 700 ᵒ C ODS-EUROFER, ε allow =~2.3% and 2.4% at RT and 700 ᵒ C Pure W, ε allow =~0.8% at 270 and 1.0% at 700 ᵒ C Pure Cu, ε allow =~15% (unirradiated) Strain Limits:

8. REPLACEABLE UNIT FOR THE SECTOR MAINTENANCE  Like the ARIES-AT power core configuration, the inboard blanket, outboard blanket, upper and lower He- cooled divertor are integrated with the HT shield into a replaceable unit for the sector maintenance.  All LM access pipes are designed as concentric tubes (the cold inlet flow (~650 °C) in the annulus, the hot outlet flow in the inner tube (1100 °C) ).  He access pipes are also designed as concentric tubes (700/800 °C for outer/inner tubes), and the advanced ODS steel (12CrYWTi*)is assumed for the tube material.  Like the ARIES-AT power core configuration, the inboard blanket, outboard blanket, upper and lower He- cooled divertor are integrated with the HT shield into a replaceable unit for the sector maintenance.  All LM access pipes are designed as concentric tubes (the cold inlet flow (~650 °C) in the annulus, the hot outlet flow in the inner tube (1100 °C) ).  He access pipes are also designed as concentric tubes (700/800 °C for outer/inner tubes), and the advanced ODS steel (12CrYWTi*)is assumed for the tube material. LiPb: T in =~650 ᵒ C, T exit =1100 ᵒ C He: T in =~700 ᵒ C, T exit =800 ᵒ C TAURO: LiPb: T in =~640 ᵒ C, T exit =950 ᵒ C Power conversion efficiency: ~55% with optimized compression ratio of 1.77. TAURO: LiPb: T in =~640 ᵒ C, T exit =950 ᵒ C Power conversion efficiency: ~55% with optimized compression ratio of 1.77. * R.L. Klueh, J. of Nuclear Materials, 307-311(2002) 455-465.

9. C OOLANT R OUTING FOR THE P OWER C ORE D ESIGN O PTION #1 (L I P B - COOLED HT S HIELD ) Size of the access pipes (thermal power is based on the ARIES-AT):  Circuit 1: series flow through the inboard shield and inboard blanket region Total thermal power=~354+110=464 MW Total mass flow rate=~5574 kg/s, ~348 kg/s per sector (∆T=1100-650=450 ᵒ C) Diameter of the access tube=~0.22 m (assuming v Pb-Li ≤ ~2 m/s)  Circuit 2: flow though the first outboard blanket region Total thermal power=~901 MW Total mass flow rate=~10,823 kg/s, 677 kg/s per sector Diameter of the access tube=~0.32 m (assuming v Pb-Li ≤ ~2 m/s)  Circuit 3: series flow through the outboard shield and the second outboard blanket region Total thermal power=~142+70=212 MW Total mass flow rate=~2547 kg/s, ~159 kg/s per sector Diameter of the access tube=~0.08 m (assuming v Pb-Li ≤ ~2 m/s)  Circuit 4: Helium-cooled the upper divertor Total thermal power=~148 MW Total mass flow rate=~285 kg/s, ~18 kg/s per sector(∆T=800-700=100 ᵒ C, P=10 MPa) Diameter of the access tube=~0.3 m (assuming v helium ≤100 m/s)  Circuit 5: Helium-cooled the lower divertor Total thermal power=~148 MW Total mass flow rate=~285 kg/s, ~18 kg/s per sector(∆T=800-700=100 ᵒ C, P=10 MPa) Diameter of the access tube=~0.3 m (assuming v helium ≤100 m/s)

10. LAYOUT OF THE COOLANT CIRCUITS AND THE ACCESS PIPES TO THE COMPONENTS Circuit 1: series flow through the inboard shield and inboard blanket region Circuit 2: flow though the first outboard blanket region Circuit 3: series flow through the outboard shield and the second outboard blanket region Circuit 4 & 5: Helium-cooled the upper and lower divertor Flow distribution

11. C UTTING /R E - WELDING OF THE A CCESS P IPES FOR S ECTOR M AINTENANCE : O PTION #1 Bottom view showing the space of all 5 access pipes penetrating through the vacuum vessel and coil structural cap. Location of cutting/re- welding  The locations of the PF coils have been modified based on the ARIES- AT’s PF coils in order to allow the gravity support of the power core and access pipes penetrating through the coil cap to connect the coolant ring header at the bottom.

12. C UTTING /R E - WELDING OF THE A CCESS P IPES FOR S ECTOR M AINTENANCE : O PTION #2  All the 5 access pipes will penetrate the vacuum port, one from upper port and 4 from the lower port.  The disconnections/connections of the access pipes are located behind the second vacuum door (the first door is the outside door).  All 5 access pipes need to be cut and removed from the port.

13. D ESIGN O PTIONS FOR R EMOVABLE V ERTICAL P OSITION AND F EEDBACK C OILS The ARIES-AT like design option: The vertical position coils and feedback coils would be attached to the vacuum door, and need to break the joints and removed horizontally. Alternative design option: The vertical position coils and feedback coils would be vertically removed up and down to the grooves of the VV. Vertical Position Coils (normal conductin g coils)  Both options work well with the configuration of the access pipes penetrating through the VV door and port.

14. P OWER C ORE C ONFIGURATION FOR THE D ESIGN O PTION #2 (H E - COOLED HT S HIELD ) 1 st design option:  LiPb flow through upper/lower divertor regions or just flow through the lower divertor region for maintaining constant velocity and avoid toroidal manifold at the inboard blanket  One LiPb circuit with 2 access pipe bundles (1/2 blanket sector per bundle) for all blankets  Need thickness inputs for both inboard and outboard HT shield  May also need a new radial build Alternative design option: ARIES-AT like configuration 3 LiPb circuits 2 Helium circuits He-cooled

15. C OOLANT R OUTING FOR THE P OWER C ORE D ESIGN O PTION #2 (H ELIUM - COOLED S HIELD )  Circuit 1: LiPb flow through both the inboard blanket and 2 outboard blanket regions Total thermal power=~354+901+142=1397 MW Mass flow rate/sector= ~1048 kg/s (∆T=1100-650=450 ᵒ C) 2 access pipe bundles including all the 24 blanket channels (0.6 x 0.6 for each bundle)  Circuit 2: Helium series flow through outboard HT shield and the upper divertor Total thermal power=~148+110=258 MW Mass flow rate/sector=~31 kg/s (∆T=800-700=100 ᵒ C, P=10 MPa) Diameter of the access tube=~0.4 m (assuming v helium ≤~100 m/s)  Circuit 3: Helium series flow through inboard shield and the lower divertor Total thermal power=~148+70=218 MW Mass flow rate/sector=~26.2 kg/s (∆T=800-700=100 ᵒ C, P=10 MPa) Diameter of the access tube=~0.36 m (assuming v helium ≤~100 m/s)

16. ACCESS PIPE BUNDLE APPLIED IN OVERALL LAYOUT FOR MINIMIZING 3D MHD ∆P (Access pipe bundle, proposed by Mark ) Constant flow cross section  Two access pipe bundles are arranged to connect all the 36 inboard and outboard blanket channels (12 for the inboard and 24 for the outboard blanket).  He-cooled HT shield may be a better design option to simplify the LiPb coolant circuits and reduce the 3D MHD uncertainty. Multiple small ducts

17. LAYOUT OF THE LIPB COOLANT CIRCUIT AND THE ACCESS PIPES FOR THE DESIGN OPTION #2 Connecting to the LiPb Ring Header ARIES-AT like design 1 st LiPb circuit Constant flow cross-section IB blanket 1 st OB blanket 2 nd OB blanket Connecting to 36 blanket channels channel by channel Cross-section of the outboard blanket channels for one half sector

18. Discussion Need to make selections:  Integration of the He-cooled divertor concepts (a few design options) Finger T-Tube Plate SiC/SiC with W coating tubular or T-tube concept Two zone divertor (any combinations)  Inboard and outboard shield (2 options) LiPb-cooled Helium-cooled  The location of the disconnections/connections of all the access pipes (2 options) Behind the outboard shield, penetrating through the bottom coil cap Behind the second vacuum door (inner), penetrating through the vacuum port  The way to remove the vertical position and feedback coils (2 options) Horizontal movement (ARIES-AT like design option): need to break the joints of the coils and remove the coils with the second vacuum door together Vertical movement: need to pull two coils up and two coils down to the grooves of the top and bottom VV parts.