Abstract
In the design of non-safety I&C system of nuclear power plants, different safety classification and power supply sequence design need to meet the characteristics of system network redundancy and self-healing. Therefore, engineers often use ring network configuration in system network design. When the ring network design or network wiring is wrong, it is easy to cause a network storm, resulting in the abnormal operation of the main control unit of the first-floor control network control station, and the mis-operation of the control unit on the field equipment, resulting in nuclear power safety accidents. This requires that the main control unit of the control station could resist the attack of network storm. This paper provides a method to prevent network storm based on link layer. The abnormal packets are filtered in the network protocol layer of the control unit, and the network storm threshold detection algorithm is used to monitor the network storm attack in time, and the network loopback protection control unit is set. Experiments show that this method can effectively resist the attack of network storm. When the main control unit is attacked by network storm, it can normally complete the task of logic unit, ensure that the field instrument and control equipment is in safe working mode, and the system can automatically return to normal state after the network storm stops. At present, this technology has been realized and applied in the digital I&C system of nuclear power plants, which has good adaptability and broad development space.
