Mechanical design of the JT-60SA cryogenic pipe system

The displacement from the assemble position of several interfaces of JT-60SA cryogenic pipe system reaches to 38 mm due to the thermal contraction and electro-magnetic force of superconducting coils. The mechanical stress on the pipe or pipe support structure by the displacement difference between interfaces is critical issue to be solved. A design concept to avoid the stress concentration on the cryogenic pipe system is bending pipe without conventional flexible tubes. In order to determine the design of the system, thermal mechanical analyses have been conducted by a finite element method software ANSYS (R). As results of analyses, it is confirmed that the final design of the system withstands the displacement and load due to the thermal contraction, electro-magnetic force, and seismic event.