HCCB TBM Mechanical Design

1. HCCB TBM Mechanical Design Presented by Ryan Hunt R. Hunt, A. Ying, M. Abdou Fusion Science & Technology Center University of California Los Angeles May 11, 2006

2. Overview • Allocated ½ Port • Design Requirements • Description of HCCB Subcomponents • Overall He Flow Routing Scheme • Assembly Process • Manufacturing Requirements Figure 1 UCLA Fusion Science & Technology Center

3. U.S. Submodule within ½ Port Figure 2 UCLA Fusion Science & Technology Center

4. TBM Design Requirements • Overall size must fit within available space (51cm x 38.9cm x 71cm) • He must cool first wall to acceptable temperatures • He must cool breeding zones • All cooling plates & manifolds must satisfy stress criteria • Helium channels (for both FW and cooling channels) must be economically fabricable • Must house appropriate amounts of breeder and beryllium multiplier • Back wall must align with JA Submodules into common ½ port back wall manifold • Must ensure survival of structural box under accidental conditions (TBD) UCLA Fusion Science & Technology Center

5. 1248 750 Connection to Port Frame Back Shield • Opening Space of 1248 x 750mm is available (minus 20mm between TBM and frame on each side for TBM grasping) • 3 Large Pipe Openings, 1 medium (instrumentation), 7 small openings • Piping must also avoid allotted space for structural attachment keys • Optimization of pipe connections and communication with IT and JA Figure 3: Front view of port frame back shield Figure 4: Back view of half-port TBM UCLA Fusion Science & Technology Center

6. Serves to collect and combine pipes from each Submodule Collaboration with JA for acceptable design/solution System of internal manifolds Keys will be too long if pipes are combined behind manifold (problems with torque) Accepts from each Submodule: 3 He coolant lines (inlet, outlet, & bypass) 2 Gas Purge Lines 1 to 2 instrumentation conduits ( = 6 to 7 lines total from each Submodule) Allowed: 3 Large Penetrations allocated to 3 main helium coolant lines 7 small penetrations 3 of 7 for purge gas outlet lines (one for each Submodule) for tritium concentration measurement 3 of 7 for purge gas inlet lines to accommodate different gas compositions for tritium (1 small penetration and 1 medium remaining for instrumentation) Common Back Wall Manifold Assembly Figure 5 UCLA Fusion Science & Technology Center

7. Overview of HCCB Sub-components • First Wall Panel • Breeder & He Channels • Internal Cooling Manifolds • Beryllium Zones • Top & Bottom Walls • Back Plates and FW He manifolds for inlet & outlet Figure 6 UCLA Fusion Science & Technology Center

8. Flow DiagramSummary UCLA Fusion Science & Technology Center

9. U.S. Planning for RAFM Steel Fabrication Technology Development for ITER TBM • Four Parallel lines of technological development planned: • Square tube manufacturing and bending to produce first-wall. • Hot Isostatic Pressing (HIP) technology to join square tubes to form the first wall, and the fabrication of other elements such as internal cooling plates and manifolds. • Investment casting as an alternative to HIP. • Reduces the need for extensive joining operations. • Reduces the amount of NDE needed (fewer joints). • Potentially less expensive than other fabrication methods. • Complex castings of 9-10 Cr steels have been produced with mechanical properties similar to those of wrought products. • Electron-beam, laser welding, and possibly other techniques to join internal cooling plates and manifolds to the first-wall structure. UCLA Fusion Science & Technology Center

10. First Wall Panel • Utilize 3 pass snaking system to distribute He • Turns in the snake achieved in back plates • Stack 16 Paths (as below) to constitute first wall Figure 7 Figure 8 UCLA Fusion Science & Technology Center

11. First Wall Fabrication • Two Methods • Components of first wall are bent into U-shape before assembly, and are then pressed between two metal plates and joined with HIPPING process • Sealing welds must be made at ends and along pipe path (likely must be done prior to giving to a manufacturing co.) • Two thicker plates each with desired half-channels milled out. Pressed and joined with HIPPING process, and finally bent into U-shape of first wall • Much more machining • Have had inaccurate channel dimensions (at corners) when bending occurs after welding UCLA Fusion Science & Technology Center

12. Back Plates • System of three metal Plates: • 5mm plate to direct inlet flow to first wall and outlet flow to outlet. • 20mm plate attached via HIP weld (alternatively have both as one thick plate ~25mm) • Once attached, sections are milled to create flow conduits • Alternatively could use investment casting to form flow conduits • Creates inlets/U-turns/outlets for the FW 3 pass snake concept • necessitates accurate welding to match back plate with each first wall path • 5mm cover with holes for inlet/outlet Figure 9 UCLA Fusion Science & Technology Center

13. Internal View of a FW Segment 1 of 16 Paths of First Wall (3 passes) He Inlet U-Turn Back Plates (Milled section) Welding Plane Figure 10: (6mm Shaved off side of Submodule to achieve the above cut view) UCLA Fusion Science & Technology Center

14. Breeder Zone Cooling Plates • Necessary Dimensions dictate geometry • (top/bottom of multiplier, breeder) • Designed as two snakes starting from sides and interweaving • Alternate Method contains 1 pass for simpler manifolds • Much cooler on one side than the other • Uneven breeder cooling • Thermal expansion problems Figure 11 UCLA Fusion Science & Technology Center

15. Breeder Coolant Channel Fabrication • Difficult as geometry is much more complex. • Options available: • Half Plates joined by Hipping. Manufactured either through: • milling and bending, or • Investment casting • 1mm square tubes stacked and HIPPED between 0.5mm plates • Entire model is cast, no HIPPING is involved. Figure 12: Example of Outer Half of Coolant Channels UCLA Fusion Science & Technology Center

16. Internal Manifolds • Allows double snake design to occur • Green diverts flow from top & bottom walls • Orange transfers flow from one pass to the next • 4 vertically & horizontally compartmented sections (TBD) • Blue is outlet collector • Tan tubes distribute flow poloidally to all parallel channels • Uneven coolant flow will make manifold design challenging Figure 13 UCLA Fusion Science & Technology Center

17. Top Wall • Accepts flow from first wall at center via back plates • Outlets to breeder zone • Number of passes and channel size • TBD as it is highly dependent on mass flow rate vs. amount of necessary cooling of wall • Thickness of wall • TBD based on stress analysis and deformation of wall • Manufactured in similar fashion as back plates Figure 14 UCLA Fusion Science & Technology Center

18. Assembly Process • Problems with welding accessibility? Figure 15 UCLA Fusion Science & Technology Center

19. Obstacles to Overcome • Thin walled members could have high deformation under thermal expansion (tolerance) • Future stress analyses will tell what thicknesses and supports will be necessary. • Very small He channels (with thin walls) are hard to manufacture • Need to decide manufacturing strategy of coolant channels and first wall channels so more detailed design can begin. • Parallel flow • Need system of baffles, buffers, and diverters to assure equal flow to all channels in Poloidal direction. • Attachments to Port Frame Back Shield • Limitation on number of pipes from Submodule means coordinated effort with JA to combine each pipe system from 3 in to 1 • i.e. each Submodule has 1 He outlet pipe = 3 total for ½ Port. Needs to be combined into a single common pipe. UCLA Fusion Science & Technology Center

20. Questions or Comments?