Speaker
Hee-Jae Ahn
(NFRI)
Description
The central solenoid (CS) of the KSTAR consists of four pairs of superconducting coils compressed axially by preloading structures. The axial pre-compression was designed to 15 MN at 5 K, which could suppress the maximum repulsive force of the coils based on reference operation scenarios. Tolerances in-between insulations, buffers, wedges, blocks and shells have been precisely controlled during the assembly of eight winding packs. Only shells of preloading structures were heated to make 6 mm gap between the preloading structure and winding pack assembly. The gap was, then, filled up by wedge movement so that axial pre-compression be applied after thermal contraction of shells. However, measured pre-compression is about 60% of the design value. A detailed investigation has been carried out to find reasons for the preloading reduction by comparing strain measurement and structural analysis results. Our study on the axial pre-compression for the CS is expected to give a guide line for future KSTAR operations.
Co-authors
H. K. Park
(NFRI, Daejeon, South Korea)
H. T. Kim
(NFRI, Daejeon, South Korea)
Hee-Jae Ahn
(NFRI, Daejeon, South Korea)
J. H. Song
(NFRI, Daejeon, South Korea)
K. R. Park
(NFRI, Daejeon, South Korea)
Y. H. Kim
(Chungnam National University, Daejeon, South Korea)
Y. O. Kim
(NFRI, Daejeon, South Korea)
