DCS two-layer network system of nuclear power plant

The invention relates to a DCS two-layer network system of a nuclear power plant, the DCS two-layer network system comprises an SCID looped network subsystem and an MNET looped network subsystem, the SCID looped network subsystem comprises a plurality of first SCID devices arranged in an operator workstation of a master control room; the plurality of second SCID devices are arranged on the simplified operator work station of the remote shutdown station; a first gateway module; a second gateway module; the plurality of first SCID devices are sequentially connected through the corresponding ring network switches according to a preset sequence to form a first branch line, and the plurality of second SCID devices are sequentially connected through the corresponding ring network switches according to the preset sequence to form a second branch line; one end of the first branch line and one end of the second branch line are respectively connected with the MNET ring network subsystem through the first gateway module