Systems Analysis Development for ARIES Next Step

C. E. Kessel1, Z. Dragojlovic2, and R. Raffrey2

1Princeton Plasma Physics Laboratory2University of California, San Diego

ARIES Next Step Meeting, June 14-15, 2007, General Atomics

Outline

• Basic systems code flow

• Explanation of what is in the Engineering Module

• Inboard thickness examples– Inboard TF coil thickness versus BT (fixed area fraction model)

– Inboard shield thickness versus Nw at plasma (Laila correlation)

• Example of rejecting power when qpeak exceeds critical value

• Scan showing impact of radiated power fraction in divertor

• Future work

Systems Code Being Developed

Plasmas that satisfy power and particle balance

Inboard radial build and engineering limits

Top and outboard build, and costing

physics engineering build out/cost

Systems analysis flow

Scan several plasma parameters to generate large database of physics operating points

Screen physics operating points thru physics filters, engineering feasibility, and engineering filters

Surviving feasible operating points are built out and costed, graphical display of parameters (COE)

Engineering Module: Physics Filters, Engineering Feasibility, and Engineering

FiltersExample of physics filter:

PCD > Paux, reject operating pointfBS > 1.0, reject operating point

Determine plasma power and radiated power from core/mantle:Pplas = Palpha + Paux

Prad = Pbrem + Pcycl + Pline

Calculate average and peak heat flux on FW:Qpeak

FW = Prad x fpeaking / AFW

QaveFW = Prad/AFW

AFW = 2R x 2a x √(1+2)/2*If Qpeak

FW > 1.0 MW/m2, reject operating point

Calculate power to divertor:Pdiv = Pplas - Prad

Pdivrad = Pdiv x fdiv

rad

Poutboardcond = (Pdiv - Pdiv

rad) x foutboard

Pinboardcond = (Pdiv - Pdiv

rad) x finboard

Engineering Module: Physics Filters, Engineering Feasibility, and Engineering

Filters Cont’d

Qpeakdiv,out = Poutboard

cond / [2(R-a/2) x fexpout x pow]

Qpeakdiv,in = Pinboard

cond / [2(R-a) x fexpin x pow]

Qpeakdiv,rad,out = (Pdiv

rad x fdivrad,out) / [2(R-a/2) x 2 x (a/2)]

Qpeakdiv,rad,in = (Pdiv

rad x fdivrad,in) / [2(R-a) x 2 x (a/4)]

Qpeakout = Qpeak

div,out + Qpeakdiv,rad,out

Qpeakin = Qpeak

div,in + Qpeakdiv,rad,in

If Qpeakout or Qpeak

in > 20 MW/m2, reject operating points

Neutron powers:Pneut = 4 x Palpha / 5Pneut2 = Mblkt x Pneut

Electric Power:Pelec = th x [Pneut2 + (Pplas - Pplasx)] x (1 - fpump - fsubs) - Paux / aux

If Qpeakout or Qpeak

in > 12 MW/m2, reject powerIf Qpeak

FW > 0.75 MW/m2, reject powerPrecir = Paux / aux + th x [Pneut2 + (Pplas - Pplasx)] x (fpump - fsubs)

Engineering Module: Physics Filters, Engineering Feasibility, and Engineering

Filters Cont’d

Inboard Radial Build: (red signifies model available)SOL, FW, gap1, blkt, gap2, shld, gap3, VV, gap4, TF, gap5, BC, gap6, PF

shld = 0.24 + 0.067 x ln(Nw/3.26)

TF coil:ITF = BT x 2R / (oNTF)RTF

out = R - a - SOL - FW - gap1 - blkt - gap2 - shld - gap3 - VV - gap4

BTmax = oNTFITF / 2RTF

out

If BTmax > 21 T, reject operating point

JTFoverall = [0.9 x all - (Bt

max)2 / 2o] / [all x (1/JSC +1/Jcu + (R Btmax / ) x

ln(RTFoutboard / RTF

inboard) - Cu / Jcu]ATF = NTFITF / JTF

overall

RTFin = √[(RTF

out) - ATF / ]Also have a fixed area fraction model, and a stress model

Engineering Module: Physics Filters, Engineering Feasibility, and Engineering

Filters Cont’d

Bucking Cylinder:RBC

out = RTFin - gap5

hBC = 1.2 x (2a)Pressure = (RBC

out / RTFave) x [(BT

max)2 / 2o]RBC

in = √[(RBCout)2 x (1 - (2 x Pressure) / BC

max))]Also a buckling limit, not checked yet

PF coil: (center stack only)RPF

out = RBCin - gap6

hPF = hBC

= oRIp x (lext + (li / 2) + Cejima)BPF

max = / (2 x RPFout)

If BPFmax > 16 T, reject operating point

Loop over RPFin, to reach JSC < JSC

lim

Engineering Module: Physics Filters, Engineering Feasibility, and Engineering

Filters Cont’d

Examples of Engineering Filters:975 ≤ Pelec ≤ 1025 ---> to isolate 1000 MWe points

Paux ≤ 80 MW ---> isolate lowest auxiliary power solutions (similar to lowest Precir, but not exactly)

0.25 ≤ (Pdivrad / Pdiv) ≤ 0.75 ---> isolate radiated power

fraction to have feasible divertor design and power balance

BT < 6 T versus BT < 10 T ---> examine how being more aggressive on magnets can enlarge your operating space

……

Systems Code Test: Physics Database Intended to Include ARIES-AT Type Solutions

Physics input: (not scanned)A = 4.0= 0.7n = 0.45T = 0.964= 2.1li = 0.5Cejim = 0.45CD = 0.38rCD = 0.2Hmin = 0.5Hmax = 4.0Zimp1 = 4.0fimp1 = 0.02Zimp2 = 0.0015fimp2 = 18.0Tedge /T(0) = 0.0nedge /n(0) = 0.27

Physics input: (scanned)BT = 5.0-10.0 TN = 0.03-0.06q95 = 3.2-4.0n/nGr = 0.4-1.0Q = 25-50He

*/E = 5-10R = 4.8-7.8 m

Generated 408780 physics operating points

TF Coil Thickness versus BT, Using 3 Different Models

Inboard Shield Thickness versus Nw at the Plasma

Impact of Rejecting Power in Divertor and FW if Qpeak Exceeds a Limit

We have thrown out operating points that can not produce Pelec = 1000 MW, when divertor/FW power is rejected, but we have also brought in higher Pfusion operating points with enough neutron power to compensate

Examine Impact of Radiated Power Fraction in the Divertor

• The plasma power is given by Palpha + Paux

• Some of this power is radiated from the plasma core/mantle to the first wall, Pbrem + Pcycl + Pline

• The remainder goes to the divertor– We then assume some fraction is radiated in the high density / low

temperature divertor slot– What ever is not radiated is conducted along the field line to the

target plate

• Examine the difference in surviving operation space when fdiv, rad is 30, 60, and 90%

• Use same physics database, and engineering module with divertor and FW heat rejection when the heat flux is too high, and blanket sizing from Laila’s correlation

Scan of fdiv,rad

Only at high radiated power fraction can we access the small major radius plasmas, and low peak heat flux in outboard divertor

ITER ELMy H-mode Pfusion

ITER ELMy H-mode Paux

ITER

Scan of fdiv,rad

ITER

Scan of fdiv,rad

ITERITER

Scan of fdiv,rad

ITER

Future Work

• Now that costing is available, coordinate scans with Zoran, and begin looking at technical trends and graphical presentation

– Need to exercise the systems code to decide what needs to be done

• Physics module– Have numerical volume, area, perimeter calculation, will incorporate and

make consistent with artificial flux surfaces– Separate electron and ion power balances have been worked out, need to

input Ee (or Ei) to solve equations

– Have input specification for ITER H-mode and SS mode, working on ARIES-I, etc.

– Multiple fusion reactions, etc, etc

• Engineering Module– PF coil algorithm based on plasma boundary and coil contour– Any upgrades to TF model?– Even if blanket can only be treated by neutronics, can a model be made for

VV, etc, etc