SUPERCRITICAL HELIUM COOLING SYSTEM AND METHOD FOR OPERATING THE SAME

摘要

PURPOSE: To improve a cooling rate more than an expansion valve even when the pressure of helium gas cooling a member to be cooled is varied and to realize an efficient operation of supercritical helium cooling by providing an expansion turbine after the member to be cooled in a passage. CONSTITUTION: Helium gas is compressed and circulated by a compressor 1 and this high-pressure helium gas is heat-exchanged with return helium gas by heat exchangers 11a to 11f so that a cooling is carried out. Further, the high-pressure helium gas is adiabatically expanded to generate cold by an expander 31a arranged in a line branched from a part of the high-pressure helium gas and meeting the return helium gas. Remaining helium gas is cooled by a means 11g to a low temperature. The cooled helium gas is cooled by heat- exchanging with liquid helium in a cooling means 23 and liquid to be cooled is cooled by the cooled helium gas. Then, the cooled helium gas is adiabatically expanded by an expansion turbine 31b and then the expanded helium gas meets return low-pressure helium gas.