Abstract: The common cause failure(CCF) due to the software design of the digital safety class instrument and control (I&C) system based on micro-processor technology for NPP is resolved by the diversity measures implemented based on FPGA, which could prevent the failure of the reactor protection system (RPS) when the Anticipated Transients Without Scram (ATWS) occurs. This paper presents the design of overall system, platform hardware and platform logic implemented with FPGA technology. The design is further validated for its capability and performance by RPS system of a nuclear power plant, demonstrating that the DCS system in this study is consistent to the requirement of digital safety I&C for NPP on feasibility, applicability and reliability.