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, 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-modeH98 ≤ 1.1

AT-modeH98 ≤ 2.0FIRE

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

physics engineering build 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: PCD ≤ Paux

– Feasible inboard radial build (SOL, FW, gap1, blkt, gap2, shld, gap3, VV, gap4, TF, gap5, BC, gap6, PF)

– Pelec = th(PnxMn+Pplas)x(1-fpump-fsubs) - Paux/ aux

– FW peak surface heat flux limit (≤ 0.5-1.0 MW/m2)– Divertor peak heat flux (conduction+radiation, ≤ 20 MW/m2)– BT,max ≤ BT,max

limit, jsc ≤ jsc,max(BT,max)– Bucking cylinder pressure– BPF,max ≤ BPF,max

limit, jsc ≤ jsc,max(BPF,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

BT

AN

q95 or cyl

n

T

n/nGr

tflattop

He

*/E

li Cejim

breakdown

CD

PCD

rCD

CD1

PCD1

fCD1

rCD1

CD2

PCD2

fCD2

rCD2

CD3

PCD3

fCD3

rCD3

CD4

PCD4

fCD4

rCD4

Hmin

Hmax

R

2

Zimp1

fimp1

Zimp2

fimp2

Zimp3

fimp3

T(0)/Tedge

n(0)/nedge

Input file #1

RABT

IP q95

t

P

N

P

Pbrem

Pcycl

Pline

PLH

Ploss/PLH

Pfusion

Paux

Pohm

<ne>n/nGr

<Te>tflattop/J

frad

Zeff

tflattop

E

P

J

fBS

Nwall

fHe

fDT

fast

H98(y,2)

Wth

consumed

Vloop

fCD

fNI

n(0)/<n>T(0)/<T>

Output file (screen)Can run a single point to determine its power balance

Physics Module Input/Assumptions

nBT

BT,start

BT,final

nN

N,start

N,final

nq95

q95,start

q95,final

nstart

final ...n

T

n/nGr

Paux

QHe

*/E

R CD

fimp1

fimp2

fimp3

Input file #2 (scan parameters)

RABT

IPN q95

qcyl

n

T

n/nGr

QH98(y,2)

J

E

p*/E

<ne>

<Te>tflattop

PLH

Nwall

Pbrem

fBS

CD

PCD

Paux

Pcycl

Pohm

Pline

fast

Zeff

T(0)/Tedge

n(0)/nedge

PCD1

PCD2

Output file (ascii datafile)

PCD3

PCD4

fimp1

fimp2

fimp3

T(0)fCD

fNI

fHe

fDT

Wth

consumed

Vloop

n(0)/<n>T(0)/<T>t

P

P

Ploss/PLH

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= 0.7n = 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

Systems Code Test: Engineering Constraint Reduction of Physics Database

gap4i = 0.01 mTFi = solved forgap5i = 0.01 mBCi = solved forgap6i = 0.01 mPFi = solved forNTF = 16.0Btmax, limit = 21 TJsc, max, limit = 2.5x108 A/m2

jTFoverall (ARIES-I)

hBC = 1.2 x 2 x x ahPF = hBC

BPF,max,limit = 16 TJsc, max, limit = 2.5x108 A/m2

Imax = 1/2 x I (provide )PCD ≤ Paux53354 operating points survive

Engineering input/assumptions:

FW radiation peaking = 2.0QFW < 1.0 MW/m2

fdivrad = 0.65

fSOLoutboard/inboard = 0.8/0.2

fflux/angle = 10Qdiv,outboard

peak < 20 MW/m2

Qdiv,inboardpeak < 20 MW/m2

Mblkt = 1.1th/aux = 0.59/0.43fpump = 0.03fsubs = 0.04SOLi = 0.07 mFWi = 0.075 mgap1i = 0.01 mblkti = 0.35 mgap2i = 0.01 mshldi = 0.25 mgap3i = 0.01 mVV = 0.40 m

Filtering the Operating Points Further

975 ≤ Pelec (MW) ≤ 1025975 ≤ Pelec (MW) ≤ 1025Paux ≤ 40 MWR ≤ 5.5 m

ARIES-AT

Looking at a Few Points

R, m BT, T IP, MA

N, %

q95 n/nGr Q H98 Paux, MW

fBS Zeff

5.4 5.0 11 5.5 3.4 0.9 50 1.6 35 0.93 1.9

TF 0.32 BC 0.09 PF 0.05

5.1 5.5 12 5.5 3.4 1.0 50 1.5 36 0.93 2.0

TF 0.36 BC 0.10 PF 0.05

5.1 6.0 14 6.0 3.2 0.9 45 1.9 39 0.95 2.1

TF 0.40 BC 0.11 PF 0.10

4.8 6.5 13 5.5 3.4 1.0 45 1.8 39 0.93 2.1

TF 0.45 BC 0.12 PF 0.10

4.8 7.0 13 5.5 3.6 0.8 45 2.1 39 0.98 2.0

TF 0.49 BC 0.14 PF 0.10

4.8 7.5 13 5.0 4.0 0.9 50 1.9 36 0.99 2.0

TF 0.53 BC 0.15 PF 0.10

How Should We Visualize the Operating Space?

975 ≤ Pelec (MW) ≤ 1025

975 ≤ Pelec (MW) ≤ 1025, Paux ≤ 40 MW, R ≤ 5.5 m

How Should We Visualize the Operating Space?

975 ≤ Pelec (MW) ≤ 1025975 ≤ Pelec (MW) ≤ 1025Paux ≤ 40 MWR ≤ 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• …..