Official FIRE Mission Scan

1
Design Point Trade Studies
J.H. Schultz M.I.T. Plasma Science and Fusion
Center NSO PAC 2 Meeting M.I.T. Plasma
Science and Fusion Center January 17-18, 2001
2
Progress in Design Point Studies
1. IPB98(y.2) Scaling - reduced 2.0 m Wedged
FIRE from Q10 to Q5 at 10 T - parametric study
explores bucked/wedged option for cost/mission
improvements 2. Equalization of TF/CS "burn
times" - optimization of TF/CS interface 3. Scan
of A, Bt for "Fixed Mission" - Margin2 and
Margin1 4. Detailed Cost vs. Ro Sensitivities
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Sizing Model



4

Double Optimization Method
(1) TF/OH interface optimization tburn,TF
tburn,OH (TF/OH interface optimum for fixed
Ro Subtract 3 s from TF flattop for heating e.g.
24.5 s flattop 24.5 s I flattop 3 s heat
21.5 s burn No scaling of theat with plasma
parameters (2) Minimum Ro for "Mission
Margin" Mission Long-pulse a-dominated
plasmas Margin2 Qgt10 tflattop/max(tE, tp,
tJ) gt 2 Margin1 Qgt5 tflattop/max(tE, tp,
tJ) gt 1
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Double Optimization Method-II
Instead of fixing Ro and varying A Vary Ro and A,
while holding Margin1,2 Marginmin(Pa/Pheat,
tflattop/tJ) 3 Variations 1) Minimum Ro(fixed
A,B)with Mmin(Pa/Pheat, tflattop/tJ) 2) Minimum
Ro(fixed A, Bvariable _at_ low A) MConst 3)
Minimum Ro(fixed A,B, f(q) _at_ high B) MConst
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Dimensionless Margins gt 2 vs. A
Alpha marginTime margin2 at optimum
A2.0/0.525 Rapid rise in time margin and heating
margin off optimum A
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Reduced Mission M1, Q5,tburn/tJ1
R o,min 1.59 m at Bt11.5 T
A(2.0/0.525)3.8095 Bt11.5 T for A3.8 Bt10.5
T for A3.6 R(low A) nonlinear, but not
pathological
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Ro (m) vs. Bt M2, Q10, t/tauJ2
Ro (m) grows pathologically at high Bt and
qlim3.1 Well-behaved if M2,Q10,t/tJ2 (qlim gt
3.1 at BtgtBt,opt)
Romin1.86 m, A3.8 Romin (A3.6) 1.925 m
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Ro (m) vs. A M2, Q10,t/tauJ2 Bt10.5, 11.5
T, qlim3.177
Romin 1.86 m_at_ Bt11.5, A3.8 Ro (m)
pathological at low A Cured by lowering Bt Q10,
M2 (no effect on Romin)
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Comparison of "Mission Margin" 1, 2 Curves
M2Minimum Cost 1.06 B _at_ Ro 1.86 m, A3.8,
Bt11.5 T - M2 lt 1 B, if phase auxiliary
power M1Minimum Cost 0.92 B _at_ Ro1.59 m,
A3.8, Bt11.5 T
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Cost (M) vs. Ro (m) Subsystem Sensitivity
Vary Ro Bt11.5 T, A3.8, qL3.1, not fixed
mission /Ro Sensitivity 1.01
/Ro Paux, IC 0 Magnets1.64 Basic
Machine1.25 Buildings1.14
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Exciting
Conclusions
Ro can be reduced to 1.86 m and retain M2
mission Mission reduction x 2 allows reduction of
Ro to 1.59 m (1st order!) Margin2 mission
requires lowering B _at_ Alt3.5 or q _at_ Bgt13 T d/dR
1 Machine sensitivity 1.25 nearly fixed
costs Recommendation Reduce Ro to 1.87 m, Day 1
RF 10 MW Achieve all cost/mission objectives
Q10, tflat/tJ2, Costlt1 B Historic first A
noncatastrophic reduction in NSO Ro