Chernobyl was indeed Grade 7, but the hazard and index were 180 times of the Grade 7 standard, and the hazard was particularly serious.

Without the stupid command of the Japanese Atomic Energy Department, the Fukushima nuclear accident would have been at most 4 -5, but because of this series of commands, it eventually rose to 7, and the measured radiation value was about 1.6 times of the 7-level standard. The damage is not as intuitive as Chernobyl, but it is lasting, especially in countries along the Pacific Ocean.