Commissioning Test Results of Variable-Temperature Helium Refrigerator/Liquefier for NIFS Superconducting Magnet Test Facility

• Published in: IEEE transactions on applied superconductivity Vol. 26; no. 3; pp. 1 - 4
• Main Authors: Hamaguchi, S., Iwamoto, A., Takahata, K., Takada, S., Imagawa, S., Mito, T., Moriuchi, S., Oba, K., Takami, S., Higaki, H., Kumaki, T., Nadehara, K.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-04-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Borides; Commissioning; commissioning test; Cooling; Cryogenics; Heating; Helium; helium refrigerator/liquefier; Liquefiers; Refrigerators; superconducting magnet; Superconducting magnets; Superconductivity; Temperature distribution; Test facilities; test facility; variable temperature; variable temperature; Commissioning test; test facility; helium refrigerator/liquefier; superconducting magnet
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2016.2525935

The superconducting magnet test facility in the National Institute for Fusion Science has been upgraded for excitation tests at a wide temperature range and a higher magnetic field of 13 T. As part of the upgrade, the helium refrigerator/liquefier that operated for 24 years was replaced with a variable-temperature helium refrigerator/liquefier. The required liquefaction rate is 250 L/h, and the required refrigeration capacity is 600 W at 4.5 K, same as the previous one. In addition, it has a new feature that can supply helium gas of a wide temperature range. The typical design cooling capacity is 1 kW under the condition of 20-K supply/30-K return and 1.5 kW under the condition of 40-K supply/50-K return. After the replacement, a series of commissioning tests were performed under the various operational conditions. From the results, the satisfactory thermodynamic performance was confirmed. In the future, it is expected that the substantial progress will be made in the development of large-scale superconducting magnets with advanced superconductors such as high-temperature superconductors and MgB2. The design of the variable-temperature helium refrigerator/liquefier and the results of the commissioning tests are reported in detail.