Abstract: An emergency system of nuclear facility includes a gas turbine generator 35 serving as an emergency power supply that can supply power to the nuclear facility, a separation valve 38 that can separate an interior and an exterior of a containment vessel 10 from each other at a time of an accident in the nuclear facility, a battery 39 that can supply power to the separation valve 38 at a time of loss of the power from the external power supply, and a control device 32 that can control operations of the gas turbine generator 35, the separation valve 38, and the battery 39, wherein when loss of the power from the external power supply and an accident in the nuclear facility occur, the control device 32 starts the gas turbine generator 35 and closes the separation valve 38 to which power is supplied from the battery 39.