Sensitivity analysis on the effect of software-induced common cause failure probability in the computer-based reactor trip system unavailability

► Importance and sensitivity analysis has been performed for a digitized reactor trip system. ► The results show acceptable trip unavailability, for software failure probabilities below 1E−4. ► However, the value of Fussell-Vesley indicates that software common cause failure is still risk significant. ► Diversity and effective test is founded beneficial to reduce software contribution.