Construction and Commissioning Tests of a 10 kW Class Helium Refrigerator for the Large Helical Device
The Large Helical Device is a heliotron fusion experimental device in which magnetic fields are controlled exclusively by superconducting coils: a pair of helical coils and three pairs of poloidal coils1. The helium refrigerator in the LHD cryogenic system has a design capacity of 5700 W refrigeration at 4.4 K, plus 650 L/h liquefaction and 20600 W refrigeration between 40 and 80 K. The contract was signed in July 1992 and the construction at the site (Toki-city, Japan.) was completed at the end of 1994. Subsequently, a series of commissioning runs were made and various design performances are being confirmed. These include the independent and combined runs of 8 compressors at full power under the helium operating conditions, a demonstration of the helium purifier, and the manual or automatic liquefaction operations that use VME controllers with a newly developed distributed control system software. These results demonstrate that the refrigerator has a satisfactory thermodynamic performance in general.
KeywordsHeat Load Helical Coil Heat Leak Flow Control Valve Compression Pressure Ratio
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- 2.Satoh, S. et al., Construction of a 10-kW-class helium cryogenic system for the Large Helical Device, Cryogenics, 1994, vol. 34, ICEC supplement 95–98, (1994).Google Scholar