Structural analysis and fatigue test of helium inlet for EAST PF8 coil

In order to solve the leakage of the helium inlet of East PF8 coil, four kinds of working conditions are established by analyzing the boundary conditions of the current structure of helium inlet. The finite element model of PF8 helium inlet is established, and the static analysis under the four working conditions is carried out. The calculation results show that thermal load and enforced displacement from the fixed support plate G11 are the main reasons of weld failure. The fatigue test of a full-size PF8 helium inlet sample has been carried out at 4.5 K and with more than 2 × 10⁵ cycles, which satisfies EAST requirement. Through detaching the PF8 helium pipe from the G11 plate, the additional loads are completely avoided, and the repaired PF8 helium inlet has good structural performance and meets the requirements of EAST. (authors)