Systems Analysis Development for ARIES Next Step C. E. Kessel 1, Z. Dragojlovic 2, and R. Raffrey 2 1 Princeton Plasma Physics Laboratory 2 University of California, San Diego ARIES Next Step Meeting, April 3-4, 2007, UCSD

Motivation for a “New” Systems Code Systems codes are critical tools in fusion design, because they integrate physics, engineering, design and costing –Scanning can be done with simple models –Results from detailed analysis can be incorporated for more specific searches Our ARIES Systems Code (ASC) has become very cumbersome and has lost its technical maintenance (primarily physics and engineering) The approach taken by most (if not all) systems codes has been to produce an optimal operating point, which is often difficult to justify, why is it optimal? This does not utilize the power of a systems code, which is to generate many operating points (operating space approach)

Operating Space Approach to Systems Analysis On the FIRE project I developed a systems code that combined physics and engineering analysis for a burning plasma experiment, which found the minimum major radius solution within several constraints For Snowmass 2002 I took the physics part out, and began to use it to generate many physics operating points, that satisfied multiple physics boundaries/constraints ---> physics operating space Finally I started to use a second code that took the all the viable physics operating points and imposed engineering constraints (divertor heat load, FW surface heat load, nuclear heating, TF coil heating, PF coil heating, etc) and physics filters to find feasible operating space

Operating Space Approach: Feasible Operating Space (Physics and Engr.) ELMy H-mode H 98 ≤ 1.1 AT-mode H 98 ≤ 2.0 FIRE

The Operating Space Approach Has Several Advantages Operating space approach to systems analysis makes the effect of constraints more transparent Many constraints carry a lot of uncertainty, which can be quantified Sequencing the analysis through 1) physics operating space, 2) engineering operating space, and 3) device build and cost, will provide a better explanation of available operating points and why they are desirable

Systems Code Being Developed Plasmas that satisfy power and particle balance Inboard radial build and engineering limits Top and outboard build, and costing physicsengineeringbuild out/cost Large systems scans Targeted systems scans Operating point search and sensitivity scans, supported by detailed analysis Systems applications Systems analysis flow

Systems Code Being Developed Physics module: –Plasma geometry (R, a, , ,  o,  I ) –Power and particle balance –Bremsstrahlung, cyclotron, line radiation –Up to 4 heating/CD sources –Up to 3 impurities beyond e, DT, and He –Bootstrap current, flux consumption, fast beta –….. Engineering module: –Physics filters: P CD ≤ P aux –Feasible inboard radial build (  SOL,  FW,  gap1,  blkt,  gap2,  shld,  gap3,  VV,  gap4,  TF,  gap5,  BC,  gap6,  PF ) –P elec =  th (P n xM n +P plas )x(1-f pump -f subs ) - P aux /  aux –FW peak surface heat flux limit (≤ MW/m 2 ) –Divertor peak heat flux (conduction+radiation, ≤ 20 MW/m 2 ) –B T,max ≤ B T,max limit, j sc ≤ j sc,max (B T,max ) –Bucking cylinder pressure –B PF,max ≤ B PF,max limit, j sc ≤ j sc,max (B PF,max ) –…..

Systems Code Being Developed Device Buildout (develop outboard description) and Costing –TF coil shape, full sector maintenance –PF coil layout –Divertor layout –Extension of inboard build to outboard, VV, shield, BC, etc. –Outboard radial build (different from inboard) –Volume/mass calculation –Costing –……

Physics Module Input/Assumptions B T A  N q 95 or cyl   n  T n/n Gr  t flattop   He * /  E li C ejim  breakdown  CD P CD r CD  CD1 P CD1 f CD1 r CD1  CD2 P CD2 f CD2 r CD2  CD3 P CD3 f CD3 r CD3  CD4 P CD4 f CD4 r CD4 H min H max R  2 Z imp1 f imp1 Z imp2 f imp2 Z imp3 f imp3 T(0)/T edge n(0)/n edge Input file #1 R A B T I P  q 95  t  P  N P  P brem P cycl P line P LH P loss /P LH P fusion P aux P ohm n/n Gr t flattop /  J f rad Z eff t flattop  E  P  J f BS N wall f He f DT  fast H 98(y,2) W th  consumed V loop f CD f NI n(0)/ T(0)/ Output file (screen) Can run a single point to determine its power balance

Physics Module Input/Assumptions nB T B T,start B T,final n  N  N,start  N,final nq 95 q 95,start q 95,final n   start  final.  n  T n/n Gr P aux Q   He * /  E R  CD f imp1 f imp2 f imp3 Input file #2 (scan parameters) R A B T I P  N q 95 q cyl   n  T n/n Gr Q  H 98(y,2)  J  E  p * /  E t flattop P LH N wall P brem f BS  CD P CD P aux P cycl P ohm P line  fast Z eff T(0)/T edge n(0)/n edge P CD1 P CD2 Output file (ascii datafile) P CD3 P CD4 f imp1 f imp2 f imp3 T(0) f CD f NI f He f DT W th  consumed V loop n(0)/ T(0)/  t  P P  P loss /P LH Can run many points by scanning a variable, and writing a out data

Systems Code Test: Physics Database Intended to Include ARIES-AT Type Solutions Physics input: (not scanned) A = 4.0  = 0.7  n = 0.45  T =  = 2.1 li = 0.5 C ejim = 0.45  CD = 0.38 r CD = 0.2 H min = 0.5 H max = 4.0 Z imp1 = 4.0 f imp1 = 0.02 Z imp2 = f imp2 = 18.0 T edge /T(0) = 0.0 n edge /n(0) = 0.27 Physics input: (scanned) B T = T  N = q 95 = n/n Gr = Q =  He * /  E = 5-10 R = m Generated physics operating points

Systems Code Test: Engineering Constraint Reduction of Physics Database  gap4i = 0.01 m  TFi = solved for  gap5i = 0.01 m  BCi = solved for  gap6i = 0.01 m  PFi = solved for N TF = 16.0 B tmax, limit = 21 T J sc, max, limit = 2.5x10 8 A/m 2 j TF overall (ARIES-I) h BC = 1.2 x 2 x  x a h PF = h BC B PF,max,limit = 16 T J sc, max, limit = 2.5x10 8 A/m 2 I max = 1/2 x  I (provide  ) P CD ≤ P aux operating points survive Engineering input/assumptions: FW radiation peaking = 2.0 Q FW < 1.0 MW/m 2 f div rad = 0.65 f SOL outboard/inboard = 0.8/0.2 f flux/angle = 10 Q div,outboard peak < 20 MW/m 2 Q div,inboard peak < 20 MW/m 2 M blkt = 1.1  th/aux = 0.59/0.43 f pump = 0.03 f subs = 0.04  SOLi = 0.07 m  FWi = m  gap1i = 0.01 m  blkti = 0.35 m  gap2i = 0.01 m  shldi = 0.25 m  gap3i = 0.01 m  VV = 0.40 m

Filtering the Operating Points Further 975 ≤ P elec (MW) ≤ 1025 P aux ≤ 40 MW R ≤ 5.5 m ARIES-AT

Looking at a Few Points R, mB T, TI P, MA N,%N,% q 95 n/n Gr QH 98 P aux, MW f BS Z eff  TF 0.32  BC 0.09  PF  TF 0.36  BC 0.10  PF  TF 0.40  BC 0.11  PF  TF 0.45  BC 0.12  PF  TF 0.49  BC 0.14  PF  TF 0.53  BC 0.15  PF 0.10

How Should We Visualize the Operating Space? 975 ≤ P elec (MW) ≤ ≤ P elec (MW) ≤ 1025, P aux ≤ 40 MW, R ≤ 5.5 m

How Should We Visualize the Operating Space? 975 ≤ P elec (MW) ≤ 1025 P aux ≤ 40 MW R ≤ 5.5 m

Future Work - Continue to Exercise Systems Code Physics module: –Include squareness, add numerical volume/area calculation –Additional parameters to scan input file –Separate electron and ion power balance –Multiple fusion reactions? –Reproduce other operating points (ITER, FIRE, ARIES-I, ARIES- ST, etc.) Engineering module: –Refine FW and divertor heating models –Is there an approximate neutronics model for inboard radial build? –Examine more complex power conversion cycles –Establish a general TF coil model –Examine PF equilibrium solutions –Anticipate detailed analysis constraints/inputs to systems code –Plotting and outputing results of scans/filters etc.

Neutronics for Inboard Radial Build FW/Blanket lifetime limited by damage/gas production > 2 years Shield limited by damage/gas production > 7 years VV is lifetime component, reweldability FW/Blanket/Shield/VV provides neutron attenuation at TF magnet (nuclear heating, Cu damage, insulator dose, …) Blanket provides limited tritium breeding Deposited surface heat flux removed by FW Deposited volumetric heating removed by FW/Blanket/Shield Generic material fractions in each component Estimates for neutron power fraction to inboard …..