A field-programmable gate array (FPGA) is a type of integrated circuit that is programmed after being manufactured. These FPGA-based systems are considered to be viable alternatives to replace many obsolete instrumentation and control (I&C) systems that are used in nuclear plants. This paper describes an FPGA-based lab-scale implementation of a postaccident monitoring system (PAMS), for a Westinghouse AP1000 reactor. This system will monitor vital parameters in the event of a serious reactor accident. The system reliability was analyzed using the dynamic flowgraph methodology (DFM). DFM was applied to fine-tune the design parameters by determining the potential causes of faults in the design.