Status Report and Documentation of DCLL Design He primary and secondary loops footprint at TCWS DCLL design evolution DCLL, DEMO inboard routing assessment Documentation of DCLL design Clement Wong, Dick Phelps, Raymond Yuhasz Mohamed Dagher, Sergey Smolentsev Edward Marriot, Mohamed Sawan Siegfried Malang General Atomics UCLA UW, Madison Consultant FNST Meeting, August 12-14, 2008, UCLA
DCLL TBM Concept Helium cooled FW and blanket structure, made of Reduced Activation Ferritic Steel (RAFS) Helium is also used for first wall/blanket preheat and tritium control. Breeder is self-cooled PbLi moving at a slow velocity < 10 cm/s. allowing high Tout (700 C) leading to gross ηth > 40% (CCGT) Use SiC flow channel inserts (FCI) to: provide electrical and thermal insulation to reduce MHD pressure drop and to decouple high temperature PbLi from cooler RAFS Front DCLL Evolution: Developed in ARIES ST,US APEX and in the EU PPS Adopted for ARIES CS Similar concept considered in US IFE HAPL program PbLi Flow Channels He PbLi SiC FCI back 5 mm He cooled First Wall 484 mm He 2 mm gap
Four TBM Interface Areas 3. TCWS Area TBM Port Plug 1. Port Cell Area 4. Tritium Plant Area Not indicated here Cooling lines US DCLL two helium loops systems DCLL ancillary Equipment 2. Hot Cell Area Port plug transporter cask TBWG-18 meeting, March 20, 2007 3
DCLL Primary and Secondary He loops Major Equipment (Generated for TCWS footprint assessment) Including Pressure Control System (PCS), and the combined Coolant Purification system (CPS) and Tritium Extraction System (TES) Location # of units Size (m) He/water heat exchanger TCWS 2 0.22Dia x 0.63 L He circulator + motor TCWS 2 1.0 Dia x 2 L Electric heater system TCWS 2 0.35 Dia x 1.65 L Circulator inlet cooler TCWS 2 0.4 Dia x 3 L Dust filter TCWS 2 0.4 Dia x 2.5 L Oxidizer element TCWS 2 0.4 Dia x 2.6 L Dessicant adsorber TCWS 2 0.4 Dia x 2.6 L Gas to gas heat exchanger TCWS 2 0.4 Dia x 2.6 L Cryogenic absorber TCWS 2 0.4 Dia x 2.6 L Electrical cubicle TCWS 2 0.5 W x 4.8 L He storage tank TCWS 8 0.4 Dia x 2.6 L Helium dump tank TCWS 2 0.4 Dia x 2.6 L Buffer tank TCWS 2 0.4 Dia x 2.6 L Compressor TCWS 2 0.68 W x 1.4 L
Pressure Control System DCLL Primary He Loop at TCWS
DCLL Primary He Loop Elevation View He lines Water lines
DCLL Primary and Secondary He Loops Plan View
DCLL Helium Loops Layout Not optimized and not all piping thermal Insulations are indicated
DCLL Helium Loops Front View Layout With insulation Not optimized and not all piping thermal Insulations are indicated
DCLL Helium Loops Layout RHS Elevation Not optimized and not all piping thermal Insulations are indicated
DCLL Helium Loops Layout LHS Elevation Not optimized and not all piping thermal Insulations are indicated
DCLL Helium Loops Layout Plan View Key dimensions were given to ITER and the unit load of 1 ton/m 2 was proposed by IO and accepted by the US Not optimized and not all piping thermal Insulations are indicated
Evolution of the DCLL configuration design M. Dagher, E. Marriott, S. Smolentsev, S. Malang, C. Wong Compared to 2007 changes in: PbLi poloidal flow routing Helium back manifolds Grid and back plates Top and bottom plates TBWG-15, 05 TBWG-18, 07 Aug. 2008
DEMO DCLL Design MHD Assessment S. S. Smolentsev, S. Malang, M. Sawan, C. Wong DEMO revisit Neutronic revisit Inboard configuration PbLi flow parameters MHD assessment
DEMO Parameters Fusion power 2116 MW Elec. Power 1690 MWe Major radius 5.8 m Minor radius 2.6 m Plasma elongation 1.9 B T 5.02 T Neutron wall loading (Max) 3.08 MW/m 2 Surface heat flux (Max) 0.5 MW/m 2 Structural material FS (F82H) Coolant He @ 8 MPa β T, % 6.1 Β p 0.86 Ip, MA 21.9 Operation mode Steady state H98y2 1.05 n e /n GW 1
Inboard and outboard assumptions (Ref. M. Sawan s neutronics 2004 note) Outboard Radial Build 75 cm Blanket 20 cm Shield 40 cm Manifold 35 cm Vacuum Vessel Inboard Radial Build 52.5 cm Blanket 30 cm Shield 25 cm Manifold 35 cm Vacuum Vessel
DEMO inboard DCLL blanket and piping estimate Goal: To estimate the inboard PbLi routing, impacts from MHD effects limited by space and 1/r B Major radius Ro: 5.8 m Inboard radius: 3.564 m Inboard surface area: 188 m 2 Bo: 5 T at the major axis Γ n inboard average: 1.33 MW/m 2 Heat flux inboard average: 0.4 MW/m 2 Inboard column vertical height: 8.4 m Total inboard thermal power: 359.4 MW
The general geometric configuration of the He and PbLi plenum as shown in the attachment is the following: Both He and PbLi coolants are using concentric pipes. Two sets of pipes, one comes from the top and the other comes from the bottom with respective inlet and outlet channels at top and bottom. External pipe is a square pipe with 25 cm on each side. The helium and PbLi manifold pipes as shown in the attachment are placed next to each other and the longest pipe is 4.2 m, which located at the bottom sector and is used to reach module # 4. The frontal dimension of each module is 1.4 m height with 1.4 m width. There will be a total of 96 in board modules, carrying a total thermal power of 359 MW. Half of the power will be carried by the helium and half by the PbLi. Each module has one helium and one PbLi concentric pipe. For the inlet He coolant is at 350 C, it will be using the center tube, for the outlet PbLi at 700 C, it will also be using center tube. (He Tin/Tout=350/460 C, PbLi Tin/Tout=450/700 C.) Therefore, both pipes will have similar outside pipe temperatures. The PbLi flow direction in each blanket is maintained with inlet flow coming down at the back blanket channel and then going up in the front channel of the blanket. With this flow configuration, and the plenum configuration shown in the attachment, the long PbLi flow path is at the bottom modules. I have made an assessment on this concentric pipe for both the He and PbLi coolants.
Helium estimates: Tin: 350 C Tout: 460 C Pressure: 8 MPa Power carry by half of the blankets: 90 MW Plenum helium velocity: 19.5 m/s Plenum pressure drop: 1.8x10 4 Pa Pumping power: 503 KW Friction factor: 0.01 assumed with some roughening PbLi plenum estimate: Tin: 450 C Tout: 700 C Power carried by PbLi on half of the blankets: 90 MW (note we have upper and lower halves) PbLi mass flow rate for half of the inboard blanket: 1919 kg/s PbLi channel dimension: 0.25 m deep with 70% PbLi volume fraction, between R=2.49 m and R=2.24 m (B@2.24 m=12.9 T) PbLi Plenum velocity: 0.089 m/s, assuming the inclusion of 0.5 cm of FCI
Selected parameters for the longest PbLi channel. Dimension PbLi velocity Outlet PbLi circular channel radius, cm 6.5 32.4 cm/s @ 700 C Inner FS tube wall thickness, cm 0.3 Gap between FCI and FS wall, cm 0.1 FCI thickness, cm 0.5 Inlet PbLi flow channel annular 1.1 36.8 cm/s @450 C FCI thickness, cm 0.3 Gap between FCI and FS wall, cm 0.2 Outer FS tube wall thickness, cm 3.5 Total ½ width, cm 12.5
Selected parameters for the longest He flow channel. Dimension He velocity Inlet He circular channel radius, cm 6.7 38 m/s @ 350 C 2.8/1.5 Thermal insulation, cm 0.5 Inner FS tube wall thickness, cm 0.3 Outlet He flow channel annular, cm 1.5 43 m/s @460 C 10.9/6.9 Outer FS tube wall thickness, cm 3.5 Total ½ width, cm 12.5 Frictional Pressure drop, kpa /pumping power, kw for the 4.2 m long channel
Assessment of MHD pressure drop for IB DCLL blanket Sergey Smolentsev
Assumptions: - Poloidal ducts are perfectly insulating - The ring collector is outside the TF coils FLOW ΔP, MPa Flow in the poloidal blanket duct with FCI ~1.0E-04 Flow at the blanket inlet ~0.5-1 Flow at the blanket outlet ~0.5-1 Flow in the poloidal concentric pipe with FCI internal pipe: ~0.01 annulus: ~0.012 Flow in the concentric pipe in the internal pipe: ~0.25-0.5 fringing magnetic field annulus: ~0.25-0.5 Bend: poloidal to toroidal internal pipe: ~0.1-0.2 annulus: ~0.1-0.2 Total: ~1.7-3.4
Summary MHD pressure drop < 2 MPa seems to be possible, providing: (A) good enough electric insulation in poloidal flows (B) careful design for all elements of the PbLi tract For the reference IB blanket, perfect electrical insulation (0 S/m) results in a very small MHD pressure drop in the poloidal flows. The effect of finite electrical conductivity FCI (<10 S/m) in the IB blanket conditions is still unknown. (Notice that in the OB blanket, the increase of electrical conductivity from 0 to 10 S/m increased the total MHD pressure drop by <1%) Challenge: need for careful 3-D MHD analysis and bench mark by experiments
DCLL documentation suggestion Continuing work to be documented as follow: Prepare report when the task is completed Submit paper to ISFNT-9 in China, Oct. 2009 Send report to C. Wong for inclusion in the next draft of the DCLL DDD report.