Analysis of Technical and Programmatic Tradeoffs with

Systems Code

Zoran Dragojlovic, Rene Raffray, Farrokh Najmabadi, Charles Kessel

and Leslie Bromberg

ARIES-Pathways Project MeetingU.C. San Diego, March 3-4 2008

What is in The Systems CodeAlgorithm Source of Info Date Included/

Modified

Geometry of the power core. ARIES progress reports, CAD drawings. •Initially: April 2007•Last: February 2008.

Power flow•Brayton cycle efficiency.

ARIES progress reports, communications with Rene Raffray and Xueren Wang.

•Initially: April 2007•Last: February 2008.

Plasma parameters:•Geometry•Physics

Charles Kessel •April 2007

HT Shield thickness based on neutron wall load.

Laila El-Guebaly •September 2007

TF Magnet•Cross-section•Coil shape and size

Leslie Bromberg •Initially: September 2007•Last: January 2008.

Bucking Cylinder Leslie Bromberg •December 2007

PF Magnet Charles Kessel, Leslie Bromberg •Initially: December 2007.•Last: February 2008.

Costing algorithms Ronald Miller (via communication with Laila), Lester Waganer.

•Initially: June 2007•Last: February 2008

Most Recent Updates and Validation

• Engineering algorithms are completed by doing the following:– TF Coil

• Casing thickness was determined based on scalling analysis from finite element models.

• Shape matches the ARIES-AT.• Toroidal caps are added on top and bottom of the TF magnet to

increase its torsional strength.– PF Coils evenly distributed on top of the toroidal caps.– Power flow updated to match the ARIES-AT.

• LSA factors are included in the costing account estimation.

• Implementation of new costing account structure is in progress.

• The current code is validated by comparing volumes, major system parameters and costing accounts with the ARIES-AT.

Thickness of TF Coil Casing• Estimated by scaling from finite element analysis of TF magnets

used in ARIES-AT, ARIES-RS and ARIES-I.• A scaling formula for thickness was established based on simple

beam theory and a multiplier that best matches the thicknesses of the three reference magnets shown in the table.

Casing Thickness from FE

Analysis [m]

Scaling by Formula

[m]

Relative Error [%]

ARIES-AT

0.2764 0.2881 4.13

ARIES-RS

0.4213 0.4049 3.97

ARIES-I 0.6136 0.7502 20.04

1

2221

1

221

22

12

00

0

ln2ln116

336.0

R

RRR

R

RRR

RR

RBa

b

Shape of TF Coil Matches ARIES-AT• A shape based on 2 semi ellipses

was adopted based on Leslie Bromberg’s suggestion. The length of the straight line portion is proportional to the height of the X-point. Equation of the outer ellipse:

• Equation of the inner ellipse:

• Equation of the straight line:

;7.0

1

122

22

2

0

RRba

b

y

a

Rx

2

011

22

1

0

1

1

b

y

RRa

b

y

a

Rx

xp

1Rx

1.4yxp

2b

a1 a2

R2

R1

R0

X-point

ARIES-AT (dashed line)

Toroidal Caps and PF Coil

• Toroidal caps are placed on the top and bottom of the TF coil. They have the same width as the bucking cylinder. The caps touch the bucking cylinder on the inboard side and stretch until they reach the height of the Vacuum Vessel.

• Total of 36 PF coils are evenly distributed on top and bottom of the caps.

toroidal cap

bucking cylindervacuum vessel

Power Flow Schematic for ARIES-AT

• The power magnitudes are taken from the systems code output and mapped to a color bar shown on the bottom [W]. They completely match the ARIES-AT.

• Efficiency of the Brayton cycle is estimated based on the maximum neutron wall load and maximum surface heat flux. For ARIES-AT, this efficiency is 58.5%.

Validation of the Systems Code

• After the updates of the algorithms were completed, the code was validated against geometry and major physics, technology and economics parameters that define the ARIES-AT. Comparison was made for– Volumes– Power plant parameters (Table 1 in ARIES-AT

report).– Plasma parameters (Table 2 in ARIES-AT report).– First wall and blanket parameters (Table 3 in ARIES-

AT report)– Costing accounts (Table 5 in ARIES-AT report).

Comparison of Volumes for ARIES-AT

• The volumes from the present systems code are compared against those derived from the CAD drawings and those reported on the ARIES-AT web site.

• The volumes do not match exactly because we have updated the algorithms. The best example is the TF coil. However, the departure remains within reason.

PartSystems Code

Output1 [m3]

Digitized from CAD

Drawing2 [m3]ARIES-AT Report3

[m3]

Relative Difference

Between 1 and 2 [%]

Relative Difference

Between 1 and 3 [%]

Plasma 325.481 317.7018 328.528 2.42 3.35

First Wall Inboard 0.0994426

First Wall Outboard 0.3129First Wall Total 0.4123426

Blanket Outboard 5.73461 6.5724 13.61Blanket II 10 9.1507 8.87

Both Blankets on Outboard Side

15.73461 15.7231 14.3649 0.07 9.03

Blanket Inboard 2.2823 2.2962 2.3159 0.61 0.85All Blankets 18.01691 18.0193 16.6814 0.01 7.71

Replacable HT Shield - Top

0.565633 0.5193 8.54

Replacable HT Shield - Bottom

0.565633 0.5193 8.54

HT Shield 8.17978 10.5672 25.47Total Shield 9.311046 11.6058 9.9975 21.94 14.89

Vacuum Vessel 15.1972 15.6001 18.4383 2.62 16.68TF Coil 11.2529 14.77451338 27.06

Major Power Plant Parameters

• Check marks mean that the input data to the systems code match the values in the table.

• Numbers in red color are the code outputs.• Blue star means that the value is never used in the systems code.

Major Plasma Parameters of ARIES-AT

Major Parameters of First Wall and Blanket

Costing Accounts and Economic Parameters

Tradeoff Studies

• Chuck Kessel has recently provided a database of 22,952 operating points. The following parameters were scanned:– Plasma aspect ratio (A): 2.5 to 4.– Normalized beta (n): 3 to 6.– q95: 3.2 to 4.0– Plasma triangularity (): 0.6 to 0.8– Ratio of line averaged plasma density to Greenwald density

(n/nGr): 0.4 to 1.0.– Q :25 to 50– Plasma elongation (): 1.8 to 2.2– Plasma major radius ( R ): 4.8 to 7.8  (for A=2, scanned from 2.8

to 7.8)– Argon fraction:  0.1 to 0.3 %– Magnetic field at plasma major ratio (BT)  5.0 to 10.0 ( for A=2,

scanned from 1.50 to 5.5)

Location of Data Points

• Data points are evenly spaced in the R-BT plane.• There is about 300 data points at each location shown.• For today’s presentation, only 6 locations will be demonstrated, due to the

lengthy run time (~ 12 sec per data point, total 76 hours). Complete runs will be available at the end of this week.

A = 4

Cost of Electricity [mill/kWh], 2008 Cost Base, LSA = 1, A=4

• Cost of electricity is shown as a function of 4 parameters, including plasma major radius, magnetic field at plasma major radius, normal beta and Greenwald density fraction.

• More meaningful results will be shown as soon as the other data points and plasma aspect ratios are available.

n

fGW

Conclusions and Future Work

• Systems code is ready for tradeoff studies assuming the ARIES-AT design and costing account structure.

• Visualization of the complete database from Chuck will be completed by the end of this week.

• All the algorithms will be documented and documentation made available to the ARIES team.