ARIES-AT: An Advanced Tokamak, Advanced Technology Fusion Power Plant

38 Pages·2004·1.8 MB·English

by  Farrokh Najmabadi

ARIES-AT: An Advanced
Tokamak, Advanced Technology
Fusion Power Plant
Farrokh Najmabadi
University of California, San Diego,
La Jolla, CA, United States of America
9th Course on Technology of Fusion Reactors
26 July – 1 August 2004
Erice Italy
Electronic Copy: ARIES Web Site: http://aries.ucsd.edu/PUBLIC
ARIES Research Framework:
Identify Key R&D Issues and
Provide a Vision for Fusion Research
Periodic Input from Goals and Scientific & Technical
Energy Industry Requirements Achievements
Projections and
Design Options
Evaluation Based on Characterization
Customer Attributes of Critical Issues
Attractiveness Feasibility
No: Redesign Yes
Balanced Assessment of R&D Needs and
Attractiveness & Feasibility Development Plan
ARIES Designs Are Developed Based on a
Reasonable Extrapolation of Physics & Technology
ARIES Rules
ARIES Rules
(cid:190) Plasma regimes of operation are optimized based on latest experimental
(cid:190) Plasma regimes of operation are optimized based on latest experimental
achievements and/or “well-founded” theoretical predictions.
achievements and/or “well-founded” theoretical predictions.
(cid:190) Engineering system is based on “evolution” of present-day technologies, i.e.,
(cid:190) Engineering system is based on “evolution” of present-day technologies, i.e.,
they should be available at least in small samples now. Only learning-curve
they should be available at least in small samples now. Only learning-curve
cost credits are assumed in costing the system components.
cost credits are assumed in costing the system components.
Optimization involves trade-off among Physics and Engineering
Optimization involves trade-off among Physics and Engineering
constraints and parameters
constraints and parameters
(cid:190) Trade-off between vertical stability and plasma shape (and β)
(cid:190) Trade-off between vertical stability and plasma shape (and β)
and fusion core configuration and blanket thickness.
and fusion core configuration and blanket thickness.
(cid:190) Trade-off between plasma edge condition and plasma facing
(cid:190) Trade-off between plasma edge condition and plasma facing
components capabilities
components capabilities
(cid:190) ...
(cid:190) ...
Customer Requirements
Top-Level Requirements for Fusion Power Plants
Was Developed in Consultation with US Industry
Public Acceptance:
Public Acceptance:
(cid:190) No public evacuation plan is required: total dose < 1 rem at site boundary;
(cid:190) No public evacuation plan is required: total dose < 1 rem at site boundary;
(cid:190) Generated waste can be returned to environment or recycled in less than a few
(cid:190) Generated waste can be returned to environment or recycled in less than a few
hundred years (not geological time-scale);
hundred years (not geological time-scale);
(cid:190) No disturbance of public’s day-to-day activities;
(cid:190) No disturbance of public’s day-to-day activities;
(cid:190) No exposure of workers to a higher risk than other power plants;
(cid:190) No exposure of workers to a higher risk than other power plants;
Reliable Power Source:
Reliable Power Source:
(cid:190) Closed tritium fuel cycle on site;
(cid:190) Closed tritium fuel cycle on site;
(cid:190) Ability to operate at partial load conditions (50% of full power);
(cid:190) Ability to operate at partial load conditions (50% of full power);
(cid:190) Ability to maintain power core (availability > 80%);
(cid:190) Ability to maintain power core (availability > 80%);
(cid:190) Ability to operate reliably with < 0.1 major unscheduled shut-down per year.
(cid:190) Ability to operate reliably with < 0.1 major unscheduled shut-down per year.
(cid:190) Economic Competitiveness: Above requirements must be achieved
(cid:190) Economic Competitiveness: Above requirements must be achieved
simultaneously and consistent with a competitive life-cycle cost of electricity.
simultaneously and consistent with a competitive life-cycle cost of electricity.
Directions for Optimization
Translation of Requirements to GOALS for
Fusion Power Plants
Requirements:
(cid:190) Have an economically competitive life-cycle cost of electricity:
t
n • Low recirculating power (Increase plasma Q, …); COE has a “hyperbolic”
e
s dependence (∝ 1/x) and
e • High power density (Increase P ~ β2B 4 , …)
r
f T
p improvements “saturate”

m • High thermal conversion efficiency;
after certain limit
o
r
• Less-expensive systems.
f

n
o
i
t
a (cid:190) Gain Public acceptance by having excellent safety and environmental
l
o
p characteristics:
y
a a
r d
t • Use low-activation and low toxicity materials and care in design.
x -
t
e n

r e
e s
g (cid:190) Have operational reliability and high availability: e
r
r
p
a
L • Ease of maintenance o
t

e
• Design margins, and extensive R&D. s
o
l
c

y
(cid:190) Acceptable cost of development.
a
t
S
There Is Little Economic Benefit for Operating
Beyond ~ 5 MW/m2 of Wall Load (for 1000MWe)
(cid:190)
(cid:190) SSimimpplele a annaalylyssisis f foorr a a c cyylilninddrricicaal lp plalassmmaa ARIES-RS
with length L: 10
with length L:
Systems code
V
What we pay for,
FPC 9
)
h
W
k
c/ 8
(

E
O
r ∆ C
7
Hyperbolic dependence
6
0 1 2 3 4 5
Avg. wall load (MW/m2)
Hyperbolic

WWaalll ll oloaaddiningg I I ∝∝11/r/r (cid:190) Physics & Engineering constraints
w dependence (cid:190) Physics & Engineering constraints
w
∆∆ i sis s seet tb byy n neeuutrtroonn m mffpp ccaauussee d deeppaartruturere f rforomm g geeoommeetrtircicaal l
dependence e.g., high field needed
VV == π πLL ( ( 2 2rr∆∆ + + ∆ ∆22)) dependence e.g., high field needed
FPC for high load increases TF cost.
FPC for high load increases TF cost.

For r >> ∆ , V ≅ 2 π Lr∆ ∝ 1 / I
For r >> ∆ , V ≅ 2 π Lr∆ ∝ 1 / I
FPC w
FPC w (cid:190) ARIES-AT optimizes at lower
(cid:190) ARIES-AT optimizes at lower
FFoorr r r < <<< ∆ ∆ , , V VFPC≅≅ 22 π πLL ∆ ∆22≅≅ccoonnsst.t. wall loading because of high
FPC wall loading because of high
(cid:190) efficiency.
(cid:190) “Knee of the curve” is at r ≅ ∆ efficiency.
“Knee of the curve” is at r ≅ ∆
Continuity of ARIES research has led to the
progressive refinement of research
ARIES-I (1990):
• Trade-off of β with bootstrap
• High-field magnets to compensate for low β
Need high β equilibria
with high bootstrap
s ARIES-II/IV, 2nd Stability (1992):
c
i
s
• High β only with too much bootstrap
y
h
P • Marginal reduction in current-drive power

d
Need high β equilibria
e
v
o with aligned bootstrap
r
p
ARIES-RS, reverse shear (1996):
m
I
• Improvement in β and current-drive power
• Approaching COE insensitive of power density
Better bootstrap alignment
More detailed physics
ARIES-AT, reverse shear (2000):
• Approaching COE insensitive of current-drive
• High β is used to reduce toroidal field
Evolution of ARIES Designs
1st Stability, High-Field Reverse Shear
Nb Sn Tech. Option Option
3
ARIES-I’ ARIES-I ARIES-RS ARIES-AT
Major radius (m) 8.0 6.75 5.5 5.2
β (β ) 2% (2.9) 2% (3.0) 5% (4.8) 9.2% (5.4)
Ν
Peak field (T) 16 19 16 11.5
Avg. Wall Load (MW/m2) 1.5 2.5 4 3.3
Current-driver power (MW) 237 202 81 36
Recirculating Power Fraction 0.29 0.28 0.17 0.14
Thermal efficiency 0.46 0.49 0.46 0.59
Cost of Electricity (c/kWh) 10 8.2 7.5 5
Approaching COE insensitive of power density
Approaching COE insensitive of current drive