The reactor can be shutdown during emergency by cutting off the power supply to the control rod driving mechanism which then causes the control rods to drop down to the reactor core by gravity quickly and thereby stopping the nuclear fission immediately 在需要紧急停堆时, ?须切断控制棒驱动机械的电源,控制棒便会因地心吸力而快速下坠至反应堆堆芯,立即停止核裂变。