Structure of divertor plate

It was necessary for a divertor plate undergoing high temperature heat and particle load to endure thermal stresses between a protection material and a heat sink, as well as has a strong endurance also against shearing force caused by an eddy current upon plasma disruption. However, even if the protection material made of carbon material and the heat sink material made of metal materials are bonded metallurgically while adhering them in a plane, since occurrence of a great thermal stresses due to the difference of heat expansion coefficient is inevitable, there has been a worry of occurrence of cracks to damage the divertor. Then, a cooling pipe is passed through the protection material made of carbon material and then the protection material and the cooling pipe are bonded metallurgically. With such a constitution, even if thermal stresses are caused during production or use, and compressive or tensile force is caused to the joined surface, the stress concentration is not caused. Further, the production step can be simplified. (N.H.)