1. R EFINEMENT OF THE P OWER C ORE C ONFIGURATION OF THE ARIES-ACT SA X.R. Wang 1, M. S. Tillack 1, S. Malang 2 and F. Najmabadi 1 1 University of California, San Diego, CA 2 Fusion Nuclear Technology Consulting, Germany ARIES-Pathways Project Meeting UCSD, CA Jan. 23-24, 2012

2. A CTION I TEMS OF THE P OWER C ORE C ONFIGURATION 1.Need more analysis of design alternatives (and drawings) before we can make choice. 2.In particular, we need details of the new He-cooled shield design with dimensions, thermal analysis. Consider SiC coolant channels as well as steel. 3.Allow for vertical motion of upper and lower control coils. Cooling of control coils (H 2 O, He) needs to be designed (Siegfried will start to do it after the meeting) 4.Vacuum vessel needs further design definition and analysis. Clearance of sector after pipe cutting should be demonstrated. 5.Specify thickness of He and steel in divertor structure. 6.Specify blanket design parameters, dimensions. 7.Postpone change of divertor (away from He-cooled W) until we have more self- consistent edge plasma (and specification of transients).

3. ARIES-ACT SA new configuration:  Straight FW & inboard blanket is designed and extended to the bottom for easy fabrication reason.  Divertor target area is reduced from 143 m 2 to 130 m 2, and the He-cooled divertors (plate-type, finger, T-tube) will be applied.  Both OB-I and OB-II are designed with one curvature without extensions for considering feasible fabrications.  The W shells are embedded into the OB II and inboard HT shield  He-cooled high temperature shield is applied in the overall configuration, ~20% thickness is added to the HT shield based on ARIES-AT LM cooled shield (suggested by Laila).  Manifolds and access pipes for the LiPb (undergoing) Christina Koehly (KIT) will work with UCSD group for the manifold and access pipes design. ARIES-AT like manifolds are initially assumed in the CAD for the maintenance study. Manifolds and access pipes will be updated later. ARIES-ACT SA new configuration:  Straight FW & inboard blanket is designed and extended to the bottom for easy fabrication reason.  Divertor target area is reduced from 143 m 2 to 130 m 2, and the He-cooled divertors (plate-type, finger, T-tube) will be applied.  Both OB-I and OB-II are designed with one curvature without extensions for considering feasible fabrications.  The W shells are embedded into the OB II and inboard HT shield  He-cooled high temperature shield is applied in the overall configuration, ~20% thickness is added to the HT shield based on ARIES-AT LM cooled shield (suggested by Laila).  Manifolds and access pipes for the LiPb (undergoing) Christina Koehly (KIT) will work with UCSD group for the manifold and access pipes design. ARIES-AT like manifolds are initially assumed in the CAD for the maintenance study. Manifolds and access pipes will be updated later. Improvements on the Power Core Components ARIES-ACT SA(AT-like) ARIES-ACT SA(New) Radial build Inboard: FW & blanket: 0.35 cm HT shield: ~0.29 m for He cooling (@0.24 m for LiPb cooling) Outboard: 1 st blanket: 0.30 m 2 nd blanket: 0.45 m HT shield: ~0.18 m for He cooling (@0.15 m for LiPb cooling) Vertical build: Divertor structure =0.15 m, 0.03 m for helium, 0.12 m for steel structure. HT shield: 0.36 m for Helium cooling (@0.3 m for LiPb cooling) Radial build Inboard: FW & blanket: 0.35 cm HT shield: ~0.29 m for He cooling (@0.24 m for LiPb cooling) Outboard: 1 st blanket: 0.30 m 2 nd blanket: 0.45 m HT shield: ~0.18 m for He cooling (@0.15 m for LiPb cooling) Vertical build: Divertor structure =0.15 m, 0.03 m for helium, 0.12 m for steel structure. HT shield: 0.36 m for Helium cooling (@0.3 m for LiPb cooling)

4. Possible Fabrication Procedure for the Inboard Blanket 1-a 3 4-a4-b 5 1. Manufacturing separate SiC/SiC inner tube with fins and outer tube; 2. Inserting the inner tube into the outer tube and brazing (or not brazing) the fins of inner tube to the outer tube; 3. Brazing all the concentric tubes together for one blanket sector; 4. Brazing the tororidal manifold at the bottom and a cap at the top; 5. One access pipe connected to the IB. 1 1-b 2

5. Possible Fabrication Procedures for the Outboard Blanket 3 1. Manufacturing separate SiC/SiC inner tube with fins and two half outer tubes; 2. Sliding the two halves outer tube into the inner tube, and brazing the two half outer tubes in the middle, and brazing the fins of inner tube to the outer tube; 3. Brazing the all concentric tubes together for one blanket sector; 4. Brazing the inner tube of the tororidal manifold to the inner tubes of the blanket; 5. brazing the outer box at the bottom and a cap at the top. 1-a 1-b 2-a 2-b Inner tube Outer tube (upper) Outer tube (bottom) Sliding outer tube from top Sliding outer tube from bottom Brazing in the middle Outboard blanket-II 5 4

6. Vertical Shells and Kink Shell Are Embedded to the Second Outboard Blanket The kink shell (1 cm) with leads embedded to the OB Blanket-II The vertical shells (4 cm) with leads connecting to next sector Outboard blanket I and II mechanically connected together OB Blanket-II OB Blanket-I

7. Electric Connections of the Shells at the Backside of the HT Shield 2 Sectors at middle plane Mechanical connector Connections/disconnections behind the HT shield Shell lead Shield block(W) Kink shell (W) Joints for electric contact (pressure- jointed or sliding joint like ARIES- ST) Shield block(W or WC)

8. Another Option for Providing an Electric Connecting Between the Shell Leads 2 Sectors at middle plane Mechanical connector Shell lead Brazing an extension (W) to the leads at the back side of the HT shield. Brazing joints can provide an good electric conductance. Brazing an extension (W) to the leads at the back side of the HT shield. Brazing joints can provide an good electric conductance.

9. Blanket Design Considerations, Options and Optimizations  The blanket will be designed to accommodate hydrostatic pressure caused by the LiPb coolant, and the MHD pressure drop of LiPb flowing through the FW and blanket.  The design goal is to optimize the dimensions to provide a blanket design with reasonable margins on the stress limits and reduce the SiC volume fraction which will benefit tritium breeding. A: inner tubes with toroidal ribs, fins free-floating. B : fins of inner tubes fully connected to the outer tube C: fins of inner tubes not connected to the outer tube (free-floating, ARIES-AT like)  Dimensions of the OB-I Radial thickness of the first outboard blanket: 30 cm Wall thickness: 0.5 cm Flow channel of the FW, SW and BW: 0.4 mm Front wall curvature: diameter=20 cm Back wall curvature: diameter=23 cm  Dimensions of the OB Blanket-II: Radial thickness of the second outboard blanket: 45 cm Wall thickness: 0.7 cm Front wall curvature: diameter=24 cm Back wall curvature: diameter=24 cm Half sector One sector

10. Scope Structural Analyses for Optimizing the Geometry and Reducing SiC Volume Fraction A: Inner tube with a toroidal rib B: Fins of the inner tube brazed to the outer tube C: Fins of the inner tube not connected to the outer tube (free-floating, ARIES-AT like) B C A Stress limits for using in FEM analysis:  Conventional stress limits (3 S m ) can not be directly applied to ceramics.  The SiC/SiC stress limits should take into account for the non-linear elastic behavior associated with matrix micro- cracking and matrix-fiber debonding.  Based on the summary of the ARIES Town Meeting, it was recommended to limit the total combined stress to ~190 MPa.  Fins of the inner tube are fully connected to the outer tube, and assumed the ∆P MHD =~0.2 MPa.  Minimum numbers of the concentric tubes per sector may be reduced to 8.

11. Example of the Outboard Blanket for the 8 Concentric Tubes Per Sector Outboard blanket I Outboard blankets(one sector)  Dimensions of the OB-I Radial thickness of the first outboard blanket=30 cm Wall thickness=0.5 cm Flow channel thickness of the FW, SW and BW=0.4 cm Flow cross-section of the FW, 0.4 cm x 4.0 cm Front wall curvature: diameter=37 cm Back wall curvature: diameter=60 cm  Dimensions of the OB-II: Radial thickness of the second outboard blanket: 45 cm Wall thickness: 0.7 cm Flow channel thickness of the FW, SW and BW =1.0 cm Flow cross-section of the front wall, SW and BW=1.0 cm x 8.0 cm Front wall curvature: diameter=45 cm Back wall curvature: diameter=46 cm 2 cm side wall  There are a few trade-off options for the blanket configuration, parameters and dimensions. One example for the OB-I: Larger curvature like the back wall, but adding more inner fins for reducing stress. This will make the flow channel smaller and more flat.  Design iteration should be performed between tritium breeding and reasonable margins on the stress limits. Outboard blanket II

12. Example of the Stress Results for the Outboard Blanket I & II: 8 Concentric Tubes Per Sector (Deformed shape scaled by 500 times)Deformed shape scaled by 500 times) Outboard blanket I Outboard blanket II  Maximum primary stress for both OB-I and OB-II is about the same (~ 80 MPa). (σ p =~60 MPa, σ thermal =117 MPa for the ARIES-AT)

13. Side Blanket Wall without Pressure Balance Needs to be Thickened to Accommodate the Hydrostatic Pressure  The thickness of the side wall would be ~ 2 cm for accommodating the hydrostatic pressure (blanket height ~8.2 m) and MHD pressure drop of 0.2 MPa  The maximum primary stress occurs at the inner fins, and the stress can be reduced by making the fins thicker. σ=96 MPa for ∆P MHD =0.2 MPa (12 concentric tubes per sector) Deformed shape scaled by 500 times)

14. Design Considerations of the Vacuum Vessel  The vacuum vessel design must have enough space to allow for vertical motion of upper and lower control coils.  The saddle coils would be attached to the front of the vacuum door and removed together with the door during maintenance operation.  The port must have enough clearances for the sector motion.  Two possible design options : I. ARIES-AT like vacuum vessel cooled by water Inboard VV, 40 cm (13% FS, 22% H 2 O, 65% WC) Outboard VV, 25 cm (30% FS, 70% H 2 O) Top & bottom VV, 40 cm (13% FS, 22% H 2 O, 65% WC) II. Water-free vacuum vessel design, assuming 10 cm for the vacuum vessel and port in the CAD drawing  Hamed is working on the stress simulation in order to optimize the geometry considering normal pressure, overpressure loads by helium (10 MPa) rupture, or other loads. Penetrations of 5 access pipes. 3 for LiPb, 2 for Helium circuits Structure support for the feedback coils Saddle coil attached to the door  Need the inputs of the cross section and shape of the saddle coil

15. Example of the Cut View Showing the Vacuum Vessel and Ports (12/16 sectors) Saddle coils

16. Options for the Arrangements of Access Pipes for the ACT SCLL  There are 5 coolant circuits for the ACT SCLL.  There is very small penetration area through coil structure.  The locations of PF coils were changed based on the ARIES-AT and ACT 1B strawman to meet the pillars for weight support.  Need the inputs of the PF coil locations and cross sections.  There are 5 coolant circuits for the ACT SCLL.  There is very small penetration area through coil structure.  The locations of PF coils were changed based on the ARIES-AT and ACT 1B strawman to meet the pillars for weight support.  Need the inputs of the PF coil locations and cross sections. Option 1 & 2 presented at ARIES Meeting on Oct. 13-14, 2011. New Option Option 1 Option 2

17. Integration of the Fusion Power Core Components (12/16 Sectors) Need to add: structure supports of PF coils vacuum pumping ducts and cryostat more details?

18. Motion Demonstration of Allowing to Withdraw the Power Core Sector Through the Port ARIES-AT 8 cm clearance The wedges of the blanket/shield cannot be removed through the port. Top view: Cut through middle plane

19. Motion Demonstration of Allowing To Move Control Coils and the Power Core Sector Cutting and removing the pipes inside of the vacuum vessel.  Control coils are removed to upper and bottom before the sector removal.  Space to allow for inserting a rail system (ARIES-RS) when transported the sector to hot cell.  Control coils are removed to upper and bottom before the sector removal.  Space to allow for inserting a rail system (ARIES-RS) when transported the sector to hot cell. Saddle coil will be removed together with inner VV door after the access pipes cutting. Front view (vertical cutting through half the sector)

20. SUMMERY  Power core components for the ARIES ACT have been re-defined based on the sector maintenance scheme. Inboard and outboard blankets Inboard and outboard high temperature shield (no analysis) Vacuum vessel and port Divertor target plates and structure Vertical shells Control and saddle coils  Scope analysis of the blanket have been performed to optimize the geometry and reduce the SiC volume fraction based on the primary stress limits. Thermal stress analysis will be performed next.  A new option for the arrangement of the access pipes to connect the ringheaders has been proposed.  The active mid-plane coils are saddle coils, and they would be attached to the front of the vacuum door and removed together with the door during maintenance operations.  The control coils have been designed to be capable of moving upper and bottom for the sector movement.  Pressure joints (or sliding joints) have been proposed to provide the electric connections between sectors for the W shells.  Motion demonstrations for removing the control coils and the power core have been performed.

21. Future Work Thermal stress analysis for the blanket Thermal analysis for the helium-cooled HT shield Vacuum vessel needs to be refined (wall thickness) based on further analysis results