| Issues |
Tape Issue |
System Issue |
Progress |
Prospect |
| dc critical current |
x | |
300-400 A/cm at 77K 100 A/cm at 65K, 3T perp |
Good |
| Over-current fault tolerance |
x | x |
Temp limit on 1G/2G tape > 300K: cable tests ok |
Good with stabilization |
| Quench recovery (coils) |
x | x |
Detection in ac systems difficult; slow propagation |
TBD: can we make a quench not a credible event? |
| ac losses |
x | x |
Limited to date: just working with flat tapes |
Fair: can change tape geometry to reduce losses |
| Mechanical properties |
x | x |
Good: 2G better, substrate and stabilizer help |
Good but need to look at synergistic effects with T, HV |
| Cryogenics-efficiency |
| x |
10-20% of Carnot |
Fair: need 20-25%: limited R&D to date |
| Cryogenics-reliability |
| x |
95-99% |
Challenging: need 99.8-99.9%: requires redundancy but cost implications |
| Cryogenics-cost |
| x |
$100's/watt at 65-80 K |
Goal: $25/watt at 65-80 K only if high production rate |
| Electrical insulation |
x | x |
Limited effort to date: single point failure issue |
Issue: can we solve this on timescale of conductor R&D? |
