Development of a Safety I and C System for NPP

Plant Protection System (PPS) in Nuclear Power Plant (NPP) trips the reactor and mitigate accident condition during the plant abnormal or accident conditions. PPS is safety grade system, and PPS shall be developed in accordance with safety design requirements. Analog logic and relay were used in the PPS before 1980's, and digital PPS were developed in 1980's. Board level digital equipment was used for PPS in Early of 1980's, but there were limitations in the expandability and maintainability. The PLC (Programmable Logic Controller) was used for PPS in later of 1980's, which was reliable and technically proved in many industrial fields. Digital PPS and safety grade PLC are developing in the Korea Nuclear Instrumentation and Control System (KNICS) R and D project. For the optimization of PPS design, the PLC shall meet communication, real time, reliability, performance, equipment hardware qualification, and software qualification requirements. The Digital PPS and PLC to be developed in KNICS R and D project will be used for I and C systems upgrade in operating NPPs and for new I and C systems in NPPs