J." Yamamoto

K. "Noto

M. Matsukawa

T. Fujiwara

T. Onodera

"Noto,  K.

Onodera,  T.

Matsukawa,  M.

Fujiwara,  T.

Yamamoto,  J."

NIFS-Repository (National Institute for Fusion Science)

§ 19. Reinforcing Stabilization of Advanced Superconducting Wires and High Current Density Noto, K., Onodera, T., Matsukawa, M., Fujiwara, T. (Fac. of Eng., lwate Univ.) Yamamoto, j. Recently, the CuNb in-situ composite[!], has been studied as a high-strength high-con-ductivity materials. The stability of two kinds of (Nb,Ti)3Sn conductors; CuNb/(Nb,Ti)3Sn and . Cu/(Nb,Ti)3Sn is studied in order to obtain basic information about the future compact design of high field superconducting magnets using a (Nb,Ti)3Sn conductor stabilized with the high-strength high-conductivity CuNb in-situ composite. A possibility of future compact design of high field and/or large scale superconducting coils will be discussed on the basis of the ex-perimental results on minimum quench energy (MQE) and their ramp rate dependence. Figure 1 shows the specifications of the studied conductors. The coils were wound af-ter the NhJSn formation heat treatment(React and Wind method). Thermal disturbances are given by a carbon resistor. All experiments were done at 4.2K and 14.0 T in Liq. He. MQE was obtained as a minimum threshold value of thermal energy given by a heater where the coils goes to quench. A numerical analysis on the stability test was made using the two-dimensional thermal conduction equa-tion. Figure 2 shows the experimental data on the MQE for highly operating current of 0.80Ic to 0.95Ic (lc: critical current) and very small ramp rate dependence. It is found that the MQE value of the Cu/(Nb,Ti)3Sn wire is about three times lager than that of CuNb/(Nb,Ti)3Sn. This is probably due to the difference in Residual Resistivity Ratio (RRR) of stabilizers. That is, RRReu-1 00 and RRReuNb--30. Degradation in MQE due to the current ramp rate was very small. There is very small ramp rate dependence of MQE, suggesting a possibility of nearly de coil op-eration up to the very high current level. These results show there is not substantial degradation of the stability in the conductor stabilized and reinforced with CuNb in-situ composite at least near critical current, suggest-24 ing a possibility of the future compact de-sign of a high field superconducting magnet using a CuNb/(Nb,Ti)3Sn conductor. A nu-merical analysis on the stability test is in progress. CuNb/(Nb, Ti)3Sn Cu/(Nb, Ti)~Sn stabilizer Cu - 20wt.% Nb pure Cu diameter 0.8mm¢ 0.8mm¢ Sn concentration 13wt.% 13wt.% Ti concentration 1.2wt.% 1.2wt.% filament dia. 3.4 p.m 3.9 p.m filament no. 5587 5587 bronze ratio 4.09 4.09 Cu ratio(pureCu) 0.25 0.53 (Cu-Nb) 0.66 barrier Ta Ta Fig. 1 T~e specifications of the ·.Cuf(Nb,TihSn wue and the CuNb/(Nb,Ti)3Sn wire. 7~--~--~----~--~--~ 6 Ol/(Nb,Ti)3Sn I hold 0 dUdt=l[Nsl X di/dt=2(Ns 6. 5 ~4 ~ 0 3 CUW(Nb,Ti)3Sn ::s 1 B=t4m t. =0.5 [ins] 0"--__ _._ __ __._ ____ ..._ __ _.._ __ _.. 0. 75 0.8 0.85 0.9 0.95 1 IJic Fig. 2 Current and dl/dt dependence on both the· Cu/(Nb,TihSn wire and the CuNb/(Nb,Ti)3Sn wire. References 1) Noto, K., Matsukawa, M., Katagiri, K., Iwabuchi, A., Sato, T., Watanabe, K., Kawabe, H., Fukutsuka, T. and Monju, Y .: Fusion Engineering and Design 20 (1993) 455 

Reinforcing Stabilization of Advanced Superconducting Wires and High Current Density

Reinforcing Stabilization of Advanced Superconducting Wires and High Current Density

Abstract

Similar works

Full text

Available Versions

NIFS-Repository (National Institute for Fusion Science)