1. March 21-22, 2006 HAPL meeting, ORNL 1 Status of Chamber and Blanket Effort A. René Raffray UCSD With contributions from: M. Sawan B. Robson G. Sviatoslavsky J. Sethian I. Sviatoslavsky (NRL) (UW) HAPL Meeting Oak Ridge National Laboratory Oak Ridge, TN March 21-22, 2006

2. HAPL meeting, ORNL 2 Outline Chamber wall thermal response for baseline large chamber concept -350 MJ-class baseline target spectra from J. Perkins now on line -Ion photon energy deposition for new 350 MJ spectra -Resulting armor thermal response (W and SiC) Advanced chamber concept based on magnetic intervention -Chamber configuration and armor response -Results of initial blanket design and scoping analysis presented -Blanket design and neutronics (presented by G. Sviatoslavsky) -Thermal-hydraulics analysis with blanket coupled to a Brayton power cycle

3. March 21-22, 2006 HAPL meeting, ORNL 3 350 MJ-Class Baseline Target Spectra Available on Line Now Spectra of 350 MJ-class DD target from J. Perkins (Oct. 2005) has been typed as an Excel file for ease of manipulation and is available at the HAPL web site. Plots of the ion and photon spectra also available there Nuclear energy produced = 364.7 MJ; total energy including laser absorption = 367.1 MJ How should we refer to this target spectra: 350 MJ, 364.7MJ or 367 MJ ?

4. March 21-22, 2006 HAPL meeting, ORNL 4 Energy Deposition Profile in W, SiC and C for 350 MJ- Class Baseline Target Spectra Spectra in a 10.75 m Chamber

5. March 21-22, 2006 HAPL meeting, ORNL 5 Smoothness of Plot of Ion Power Deposition Profile in Armor Depends on the Assumed Time Increments Profile is more jagged for small time increments Profile much smoother for larger time increment Small time increments ( 0.05  s) used in calculations presented here 0.1  s time increment) 1  s time increment)

6. March 21-22, 2006 HAPL meeting, ORNL 6 Temperature History and Gradient for W Armor in a 10.75 m Chamber Subject to the 350 MJ-Class Baseline Target Threat Spectra 1-mm W on 3.5 mm FS at 580 °C No chamber gas Peak temperature ~2400°C (close to results from before with scaled target spectra)

7. March 21-22, 2006 HAPL meeting, ORNL 7 Temperature History and Gradient for SiC Armor in a 10.75 m Chamber Subject to the 350 MJ-Class Baseline Target Threat Spectra 1-mm SiC on 3.5 mm FS at 580 °C No chamber gas Peak temperature ~2800°C Not acceptable as sublimation temperature ~2700°C

8. March 21-22, 2006 HAPL meeting, ORNL 8 Advanced Chamber Based on Magnetic Intervention Concept (using cusp coils) Use of resistive wall (e,g SiC) in blanket to dissipate magnetic energy (>90% of ion energy can be dissipated in the walls). Initial chamber schematic from Bertie Robson (with cone-shaped chamber blanket concept). The initial configuration was rotated 90° for the blanket analysis as this seems to favor the maintenance scheme. Also Malcolm McGeoch indicated that the 40-beam approach with equalized laser paths can be adapted using one additional turning mirror to give vertical aspect ratio beams (instead of the original horizontal aspect ratio beams). This helps for positioning vertical blanket modules for ease of draining. Dump plates to accommodate all ions but at much reduced energy (10%). Dump plates could be replaced more frequently than blanket.

9. March 21-22, 2006 HAPL meeting, ORNL 9 Ion Energy Deposition and Thermal Response of Dump Plates Estimated for Cone-Shaped Chamber Duck bill configuration assumed for the equatorial ion dump ring and the top and bottom ion dump cones Example case with R max = 6 m; duck bill opening, y = 1 m; and blanket thickness ~ 0.7 m Fraction of ion energy on dumps ~ 10% Energy deposition from ions calculated by maintaining the same number of ions as in original spectra but reducing the energy to 10%of the original spectra level The time of flight of the ions will be determined by the path length along the field lines to the dump plates (assumed as 7.2 m in the results shown on the next slide) R max R min y Ion Dump Plates Blanket Thickness

10. March 21-22, 2006 HAPL meeting, ORNL 10 Temperature History of W and SiC as Armor for the Ion Dump Plates in the Magnetic Intervention Cone-Shaped Chamber The longer time of flight (due to the lower velocity associated with the low ion energy) results in a jagged ion energy deposition for small time increments and, consequently, in a jagged temperature profile. Peak temperature ~2200°C for W (probably acceptable), and ~3000°C for SiC (not acceptable). The question remains on whether the implanted He ions (with lower energy) would be released or would be trapped and results in rapid exfoliation of the armor.

11. March 21-22, 2006 HAPL meeting, ORNL 11 Temperature History of SiC Blanket Wall Under Photon Threat for Magnetic Intervention Cone-Shaped Chamber 1-mm CVD SiC on 1.4 cm SiC f /SiC at 1000 °C (fairly thick wall needed for resistive dissipation Peak temperature ~1300°C Probably acceptable for thin CVD armor layer

12. March 21-22, 2006 HAPL meeting, ORNL 12 Self-Cooled Pb-17Li Breeder with SiC f /SiC as Structural Material Considered as Blanket Concept Provides the resistive walls required for magnetic energy dissipation Build on ARIES-AT MFE concept with 2-pass flow to maximize performance: first pass through annular tube, second pass through large central channel where the Pb-17Li can be superheated Results of initial scoping analysis presented here STAY TUNED FOR DETAILS ON THE MECHANICAL DESIGN AND NEUTRONICS ANALYSIS FROM GREG ARIES-AT

13. March 21-22, 2006 HAPL meeting, ORNL 13 Self-Cooled Pb-17Li + SiC f /SiC Blanket Coupled to a Brayton Cycle though a Pb-17Li/He HX 3 Compressor stages (with 2 intercoolers) + 1 turbine stage;  P/P~0.05; 1.5 < r p < 3.5 -  T HX ~ 30°C -  comp = 0.89 -  turb = 0.93 -Effect. recup = 0.95

14. March 21-22, 2006 HAPL meeting, ORNL 14 Thermal-Hydraulic Optimization Procedure Set blanket configuration including channel and wall dimensions, blanket width and thickness from initial design parameters (from Greg’s presentation). -including: SiC f /SiC  FW =1.5 cm,  annulus =0.5 cm -only the blanket length is adjusted based on the chamber size Simple MHD assumption based on assumed 1 T field and flow laminarization (probably conservative). For given chamber size and corresponding neutron wall load, calculate combination of inlet and outlet Pb-17Li temperatures that would maximize the cycle efficiency for given SiC f /SiC temperature limit and/or Pb-17Li/SiC interface temperature limit. -SiC f /SiC T max <1000-1100°C -Pb-17Li/SiC T max <850-1000°C -Assume conservatively k=15 W/m-K for SiC f /SiC -Need to MWG input on most updated SiC f /SiC properties and temperature limits for IFE conditions

15. March 21-22, 2006 HAPL meeting, ORNL 15 Brayton Cycle Efficiency as a Function of Cone-Shaped Chamber Size and Corresponding Outlet and Inlet Pb- 17Li Temperatures SiC f /SiC T max limit really constraining Interface Pb-17Li/SiC T max < 900°C for all cases considered with SiC f /SiC T max <1000°C Interface Pb-17Li/SiC T max < 950°C for all cases considered with SiC f /SiC T max <1100°C

16. March 21-22, 2006 HAPL meeting, ORNL 16 Corresponding Pb-17Li Inlet and Outlet Temperatures Example parameters for a 6 m chamber and SiC f /SiC T max < 1000°C: Pb-17Li T in =483°C; T out = 799°C;  = 50% (can do better with larger chamber and/or more optimistic SiC f /SiC properties). In all cases, blanket Pb-17Li  P ~ 0.2 - 0.35 Mpa.

17. March 21-22, 2006 HAPL meeting, ORNL 17 Summary A scoping study has been performed of a s elf-cooled Pb-17Li + SiC f /SiC blanket concept for use in the magnetic-intervention cone-shaped chamber geometry -Simple geometry with ease of draining and accommodation of 40 rectangular laser ports with vertical aspect ratio -Good performance, with the possibility of a cycle efficiency >50% depending on chamber size and SiC f /SiC properties and temperature limits -Must realise that SiC f /SiC is an advanced material requiring substantially more R&D than more conventional structural material (e.g. FS) -SiC FW seem to be able to accommodate photon power (based on max. temp.) -The dump plate design needs to be developed in some more detail with the possibility of easy maintenance to account for more frequent replacement when compared to blanket -Requirements on dump plate comparable to entire FW for large chamber case w/o magnetic intervention, but with much higher concentration of lower energy ions (possibility of engineered W to take the stresses and release the implanted He?) Future work -More integrated design and maintenance analysis of this concept to make sure no major issue has been overlooked -Visit other options if needed - Dump plates and blanket modules at top and bottom of cone-shaped chamber need to be developed in some detail to determine feasibility