Strength analysis of cooling pipe joints for poloidal field coil for nuclear fusion equipment

A study is made to confirm the reliability of a poloidal field coil (PFC) under operating loads during the design process. One of the most important points is the evaluation of PFC fatigue strength, because the applied stress may be close to the elastic proportional limit of the copper material. A stress analysis is carried out to determine a reasonable structure for cooling pipe joints, given the limited space available for the joints. Experimental studies are also performed to evaluate the fatigue strength of pipe joints. As a result of these strength analyses, a bellows structure was selected as the most appropriate PFC cooling pipe joint. It was confirmed that such joints are strong enough to be used in PFC's. (author)