# Presentation: 488481

## Magnet costs

- L. Bromberg
- J.H. Schultz
- ARIES Meeting & Review
- PPPL, October 3-4 2006

## Superconductor Options and Implications

- Nb3Sn wind and react (most conservative)
- Conventional design (ITER-like), but with high temperature inorganic insulation
- Presently being tested for VLHC design (3-D winding in cos- magnets)
- Nb3Sn react and wind (less conservative)
- Thin cross section (low strain during winding)
- MIT magnet for LDX (floating coil)
- Low conductor current, internal dump
- High Tc (most aggressive)
- Epitaxially deposited on structure
- YBCO 2-generation superconductor
- Potential for low cost (comparable to NbTi)

- Ceramic insulation
- tape

## Costing

- Magnet costing for the ARIES magnets substantially lower than that of present designs/machines
- Cost savings due to
- Conductor improvements
- Nb3Sn and HTS (YBCO 2nd gen conductor)
- Structure improvements
- How do we evaluate “complexity?”
- Costing of superconductor in stellarator by kA/m, rather than energy or weight (because of multipole field configuration)

## Cost of 10th of a kind vs 1st of a kind

- Stellarators coils are more complex than tokamak coils
- Design, tooling, winding, position assurance much more costly for first of a kind stellarator than for tokamaks
- Modern methods of design and manufacturing avoid many of the issues of fitting, with software that goes directly from design engineer to the floor (Pro-engineer in NCSX)
- Difficulty thus relative to winding/tooling

## Winding

- Winding in stellarators is 3-D, vs ~2D winding for tokamaks
- Additional time for winding
- DB Montgomery: ~ 5 (guess)
- High energy physics ~ 3 (winding solenoids vs cos- dipoles)
- J. Schultz: ~ 1.5 (from 2D to 3D)
- Tokamaks already need 2-D winding
- not winding in tension, which would result in cheaper winding operation
- In ITER, winding to bring conductor into slots in radial plates

## Tolerance Impact on Cost

- ?

## Slide 7

## Slide 8

## Scaling Laws for Modeling Large Superconducting Solenoids, M. A. Green and A. D. McInturff, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. I I , NO. I , 2292(2001)

## Costing Methods for SC cable

- Cost analyses of superconductors for high-field magnets, Lance Cooley, LTSW 2003, Monterrey CA

## PIT(Powder_in_Tube)

- LHC-NbTi

- 27¢

- $66

- 21¢ @ 5T

## Powder in tube

## Slide 13

## HTS

- Present cost of 1st gen wire ~ 100$ kA/m (BSSCO)
- Recent breakthrough in YBCO 2nd generation (344)
- Multiple suppliers of tape (@77K)
- Nominal current ~ 60 A, but have made 300 A, 100 m lengths (AMSC, SEI)
- Extrapolation to ~ 500 A reasonable, 900A aggressive extrapolation
- At 30 K, 12 T, expected current ~ 9 kA/tape
- At 50 K, 12 T, expected current ~ 2.7 kA/tape
- Present cost 2nd gen ~ 50-100 $/kA m

## Progress in YBCO A-m

- YBCO stuck at ~ 100 A-m for nearly a decade
- Oct 2005 – Nagoya Coated Conductor Center (NCCC) at ISTEC announces 50 kA-m wire (245 A x 212 m, PLD on IBAD-GZO), x 500 improvement
- ARIES-AT: Requires tape with ~ 5 MA-m,
- x 100 over NCCC

- Other commercial apps may only require x 10-20 improvement

## Slide 16

## Dependence of Jc on T and H

- ORNL/RABITS Performance, 0.3 micron, 2000 Wire Development Workshop Proceedings, St. Petersburg, Florida, February 10-11, 2000

- Multi-Scale Characterization: Evaluation of Microstructuraland Superconducting Properties Across Multiple Length Scales in 2ndGeneration HTS Wire. Terry Holesingerand Leonardo Civale, Superconductivity Technology, ,Alamos National Laboratory DOE PEER Review 2006

## HTS costing

- At 64 K, 2 T:
- 20 $/kA m
- At 30K, large field
- 4 $/kA m, ~ independent of field
- Still more expensive than Nb3Sn (~ 2$/kA/m) @ 5 T, but not at 15 T!

## Summary

- There is a potential for VERY large decrease in the cost of SC magnets
- Development of superconductor has until recently been funded by OFES, mainly through SBIR’s
- However, recent interest from the HEP community in high field devices (including VHLC)
- Decrease in cost is associated both with improved conductor as well as improved conductor/winding concepts.