Abstract
In the JT-60SA project, the JT-60U tokamak is replaced with a full superconducting tokamak. The heliumrefrigerator cools the superconducting coils by circulating supercritical helium of 4.4 K and 0.6 MPa in the circulation loop atcertain mass flow rate. Since the cooling power of the helium refrigerator is determined by the heat load of the superconductingcoils, estimating the heat generation and required mass flow rate to acquire sufficient temperature margin is of crucial importance.In this paper, we attempted to optimize the mass flow rate in the superconducting coils to satisfy a temperature margin of 1 K. Wethen show that the consequent maximum pressure drop in the circulation loop that results in minimizing the heat load of thesupercritical helium circulation pump is 81 kPa.
