短语词组短語melt -through 全部熔化Reactor Vessel Melt -Through 壓力容器的熔融貫通core melt through 堆芯全熔化core melt through accident 堆芯全部溶化事故melt through accident 全部熔化事故through melt 通過熔融Gas blows through melt front 吹破 返回 melt through