| Nuclear power plant digital control system(DCS) refers to the control center and neural system of the nuclear power plants. By controlling, monitoring and protecting various parts and system of nuclear power plants, it ensures that nuclear power plants can be operated reliably, safely and economically. To solve the problem of communication between safety DCS system and external system, this paper presents the design as well as the implementation of gateway software in the nuclear power plants safety DCS system. The main contents and results can be listed below:First of all, this paper describes the development of domestic and foreign nuclear power plants and its control system, as well as research contents and purpose of this study. Then, by taking Ling Ao Phase II safety I&C(instrument and control) system as an example, it studies the program of nuclear power plant safety DCS system, describes the design criteria and classification of nuclear power plant DCS system, and focuses on analyzing the system components and network structure of reactor protection system(RPS), as well as the location and role of gateway in the system network. Then, it introduces the research projects of safety DCS platform of nuclear power plant the author participated in and the job contents the author is responsible for in the project.Beyond that, this paper conducts a demand analysis on the target application of gateway in the nuclear power plant DCS system. By taking system components and network structure of platform in this project as reference, it designs the overall program of operation mechanism, as well as internal and external interfaces of the gateway. Moreover, it analyses the link access procedure of traditional Modbus gateway solution and its limitation in this project, and designs a real-time data pool to solve unidirectional transmission problems in new gateway solution. Meanwhile, it analyses and realizes TCP/IP protocol, Modbus protocol and NTP protocol in the embedded environment to achieve the basic communication of gateways. Based on the demand analysis and program design requirements, the software functions of overall gateway system are designed and implemented as well.Last but not the least, this paper selects security CPU product, which is designed according to the requirements of IEC 61508 SIL-3, as hardware simulation platform to conduct simulation and verification. As shown by the results, the gateway system can reliably and safely achieve communication isolation, protocol conversion and data transfer between the safety and non-safety systems. Moreover, the gateway software has been successfully applied into the platform in this project. |
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