PLC-Based Safety Critical Software Development for Nuclear Power Plants

This paper proposes a PLC(Programmable Logic Controller)-based safety critical software development technique for nuclear power plants’ I&C software controllers. To improve software safety, we write the software requirements specification using a formal specification notation named NuSCR [1]. NuSCR specification is then mechanically transformed into semantically equivalent Function Block Diagram(FBD), a widely used PLC programming language. Finally, we manually refine the FBD programs so that redundant function blocks are identified and removed. As CASE tool supplied by PLC vendors automatically compiles the resulting FBD programs into PLC machine code, PLC software development is completed when the final FBD programs are essentially tested.