Quantitative Effect Analysis of Input Diversities for ESF Component Actuation Signal

In recent years many nuclear power plants have adopted modern digital I&C technologies since they are expected to significantly improve their performance and safety. OPR1000 in Korea (Korean standard nuclear power plant), typically Ulchin 5 & 6 nuclear units, have adopted safetycritical digital systems due to the functional advantages of smart digital systems and the obsolescence of the traditional analog components. Recently, in Korea, there are several important industrial projects aiming at the development of digitalized safety-signal generation system for nuclear power plants. Among them, one of the most active research programs, Korean Nuclear I&C System (KNICS) project produced a new design of the engineered safety feature (ESF) component control system (CCS) based on newly developed microprocessor-based modules. Notable advances of this ESF-CCS design are active applications of new technologies: the in-module-test mechanism, the hot-standby redundancy, and the network communication technology for safety signal generation. In this study, we performed sensitivity study to quantify the unavailability of newly developed ESF-CCS. And a sensitivity analysis on the effect of input diversities on the component actuation signal unavailability is investigated.