The purpose of jsri and Nippon Steel is to develop and produce the ductile iron nuclear spent fuel container with the size of 4850 mm ＞＜ 2450 mm and inner diameter of 1490 mm. The test of small proportion specimen is used to master the key technology of producing thick wall nodular iron castings. The small proportion specimen is taken as the cylinder with bottom in the test of Nippon Steel and Nippon Steel. The dimensions of nodular iron nuclear spent fuel container and small proportion specimen developed by Japan are shown in the figure.

Through strict control of chemical composition, reasonable riser design and other measures, the shrinkage defects of ductile iron nuclear spent fuel container were reduced, and the production cost was reduced. The relationship between elongation and eutectic solidification time of ductile iron studied by Japan steel company found that if the central solidification time of ductile iron with wall thickness of 500mm is less than 120 minutes, the central elongation of casting can reach more than 12%. On the basis of the research, Nippon Steel adopts the metal mold on the outside side and the chill process on the inside. The outer part of the Japanese made steel adopts metal mold, and the inner side adopts the chill and spray cooling process, and finally the performance of the small proportion sample is obtained. Although Japan has done a lot of experiments and research work, it has not been put into practical production and application.