Author(s): Zhi Xu , Daoqing Jiang
Westinghouse company (WEC) had developed a Nuclear Regulatory Commission (NRC) approved advanced logic system (ALS) platform based on field programmable gate array (FPGA) technology as the next generation 1E class platform for protection and monitoring system (PMS) development for nuclear power plants. In compliance with the requirements of typical PMS functions, a new ALS based PMS is designed by overcoming the restrictions of communication modules etc. The consistency with data communication independence and isolation, deterministic, diversity requirements etc. is analyzed. The evaluations indicate the design meets the requirements and can be applied for coming projects.
The rapid development of digital computer technology and the widely deployment in nuclear power plant results in the problem of the high complexity of instrument control system (I&C), which is being paid more and more attentions. The software common mode failure (CCF) in nuclear power plant digital control system cannot be eliminated completely with the current technology, therefore, in the development of PMS, the usage of the specific methods to deal with the problem, such as diversity design and/or diversity actuation system, is a common practice. However these methods increase the design, development and licensing difficulties and costs .
In 2004, CS Innovations Company (CSI) developed an FPGA technology based system and replaced part of the obsolete protection system inWolf Creek nuclear power plant. Based on the successful practice, CIS introduced
the ALS to industry as a safety system development platform. It is a “hard” logic based universal platform, which has the characteristics of high reliability and integrity. Main control functions do not rely on the microprocessor or software, but the simple FPGA based hardware architecture . After the acquisition of CSI, WEC continued carrying out a lot of licensing jobs and finally the final safety report was issued by NRC in September 2013. NRC approved that the platform can be used as a solution to solve the problem of diversity and defense in depth for digital safety system, which can be customized for safety system replacement or new safety system development .
To satisfy the typical PMS functional requirements, a new PMS based on ALS platform, by overcoming the restrictions of communication modules etc. with minimum development cost, is designed. Based on the requirements
in the Nureg-0800, the consistency with the rules and guidelines for the PMS in terms of data communication independence and isolation, deterministic, diversity requirements is studied.
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