Safety Activities on Safety-Critical Software for Reactor Protection System

摘要

A fully-digitalized reactor protection system (RPS), which is called the IDiPS, is being developed under the KNICS (Korea Nuclear Instrumentation & Control Systems) project in order to be used in newly-constructed nuclear power plants and also in the upgrade of existing analog-based RPSs [1]. In the KNICS project, the software for the IDiPS is being developed under a strict procedure [1] and also, independent verification & validation (V&V) activities are being arranged [2]. The IDiPS is configured based on the POSAFE-Q PLC-based platform. The software of the IDiPS is programmed by the use of a function block diagram (FBD) which is complaint with the IEC 61131-3 [3]. The software modules in the detailed design description are also represented by the FBD. In order to improve the software quality, a software safety analysis (SSA) was performed as a part of the V&V activities in the KNICS project, and the strategy and methods for the safety analysis for the FBD are presented in this paper.