The Risk Effect Analysis of the Digital Safety-Critical Systems in a Nuclear Power Plant

Abstract

The impact analysis of digital safety-critical systems, the digital plant protection system and the digital engineered safety feature actuation system, on plant risk is embodied and illustrated based on the digital systems’ fault-tree models combined with a typical PSA model of a Korean Standard Nuclear Power Plant. This paper presents the sensitivity study results which used three variables: human failure probability, software failure probability and watchdog timer coverage. The result quantitatively shows that plant risk largely depends on these variables.