Performance Tests of the Subcooling System for the LHD Helical Coils

Performance tests of the subcooling system for the helical coils in the large helical device (LHD) have been performed. For the performance of the system, it is necessary to supply the helical coils with a subcooled helium mass flow of 50 g/s at 3.2 K. From the test results, the performance was able to fulfill the design requirements of the system. Additionally, the coil temperature has been evaluated with the quasi-one dimensional numerical calculation, in which the numerical model simplifying the helical coil configuration is used. The coil temperature would be 3.6 K under a steady heat load of 100 W from outside of the coil case in the system which maintains the above performance, as the result of the calculation.