Measurement of the JcBT characteristics of NbSn superconductor for ITER

Kamikado, Takeshi*; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Koizumi, Norikiyo; Okuno, Kiyoshi

For evaluation of critical characteristics of NbSn superconductor that JAEA had developed for the ITER superconducting coil, in wide magnetic field, temperature and strain, the improvement and adjustment of the test equipment that Tsukuba Magnet lab of the NIMS owned, and the measurement of the critical current were done by a joint research. The temperature became unstable in a target temperature when using it for NbSn superconductor that the temperature is low because this device was developed to measure oxide superconductor and there was a problem that a correct measurement was not able to be done. Then, the heater controlled by temperature and the temperature sensor were newly added to the sample, it adjusted in addition according to flowing quantity and the temperature of helium that cooled the sample, and a new technique was established. And, the critical current of NbSn wire for ITER was measured by using the examination technique by magnetic field area 11-14T, temperature field 4.2-10K, and strain area -1-1%. As a result, a measurement steady in a low temperature field was able to be done, and the evaluation of a critical characteristic became possible. It was able to be confirmed to developed NbSn superconductor that there was a performance that the critical current density in the operating condition of ITER was 19% larger than the demand value, and is more enough.