Methods of software V and V for a programmable logic controller in NPPs

This paper addresses the Verification and Validation (V and V) process and methodology for embedded real time software of a safety-grade Programmable Logic Controller(PLC). This safety-grade PLC is being developed in the Korea Nuclear Instrumentation and Control System (KNICS) projects. KNICS projects are developing a Reactor Protection System(RPS) and an Engineered Safety Feature-Component Control System (ESF-CCS) as well as safety-grade PLC. Safety-grade PLC will be a major component that composes the RPS systems and ESF-CCS systems as nuclear instruments and control equipments. This paper describes the V and V guidelines and procedure, V and V environment, V and V process and methodology, and the V and V tools by the KNICS projects. Specially, it describes the real-time operating system V and V experience which corresponds to the requirement analysis phase of the software development life cycle. Main activities of the real-time operating system Software Requirement Specification(SRS) V and V of the PLC are the technical evaluation, licensing suitability evaluation, inspection and traceability analysis, formal verification, software safety analysis, and software configuration management. The proposed V and V methodology satisfies the Standard Review Plan(SRP)/Branch Technical Position(BTP)-14(MOST-KSRG 7/Appendix 15 in Korea will be issued soon) criteria for the safety software in nuclear power plants. The proposed V and V methodology is going to verify the upcoming software life cycle in the KNICS projects. (author)