Study on the heat exchange efficiency of ITER GS thermal anchor

Abstract

Thermal anchor is a key component of ITER gravity supports and serves to maintain them a temperature for the normal operation of superconducting coils. Two rows of thermal anchor pipes introduced by 80 K helium gas are connected with supports to reduce the heat transferred from pedestal ring to magnet. TIG welding is chosen as the connecting method for the attachment of thermal anchor. A prototype of GS flexible plate with thermal anchor attached is manufactured by TIG welding. And heat exchange efficiency test is done on the prototype with its thermal anchor being introduced by liquid nitrogen under a circumstance similar to ITER. Temperature of the area next to thermal anchor on the plate is about 100 K with only one pipe until temperature variation is not obvious. As helium is a quite expensive coolant for the cooling down of plate, computer simulations with 80 K helium gas being introduced into thermal anchor is performed instead. The finite element model is built and revised as per the test results. And the test results and simulations are discussed and analyzed to make sure the conductive heat from pedestal ring could be dissipated by using helium gas.