Reactor core vessel and mounting method thereof

The invention provides a reactor core vessel. The reactor core vessel comprises a main cylinder, an expansion joint assembly and a filling body; the main cylinder penetrates through the center of a diversion box and the center of a heavy water box from top to bottom in sequence; the expansion joint assembly is located at the outer side of the main cylinder, and the bottom of the expansion joint assembly is connected with a lower bottom plate of the diversion box; the filling body is located inside the main cylinder, the lower end of the filling body is connected with the upper end of a grid plate assembly, the filling body is used for filling a gap between the main cylinder and a fuel assembly, and the bottom of the grid plate assembly is connected with a lower flange of the main cylinder.Besides, the invention further provides a mounting method of the reactor core vessel. By means of the structure of the reactor core vessel, long-distance replacement can be achieved, the reactor corevessel is convenient to m