Analysis of Technical and Programmatic Tradeoffs with Systems Code

1. Analysis of Technical and Programmatic Tradeoffs with Systems Code Zoran Dragojlovic, Rene Raffray, Farrokh Najmabadi, Charles Kessel and Leslie Bromberg ARIES-Pathways Project Meeting U.C. San Diego, March 3-4 2008

2. What is in The Systems Code

3. 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.

4. 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.

5. 1.4yxp 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: X-point a1 a2 R1 2b R2 R0 ARIES-AT (dashed line)

6. Toroidal Caps and PF Coil toroidal cap • 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. vacuum vessel bucking cylinder

7. 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%.

8. 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).

9. 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.

10. 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.

11. Major Plasma Parameters of ARIES-AT

12. Major Parameters of First Wall and Blanket

13. Costing Accounts and Economic Parameters

14. 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 (bn): 3 to 6. • q95: 3.2 to 4.0 • Plasma triangularity (D): 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 (k): 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)

15. Location of Data Points A = 4 • 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.

16. 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. bn fGW

17. 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.