Optimization of software development life cycle quality for NPP safety software based on a risk-cost model

Abstract

As I&C systems in NPPs are being replaced with digital-based systems, the need for cost-effective safety-critical software engineering plans has been received increased attention. This paper proposes a framework for optimizing software development and V&V qualities by incorporating and estimating various risk-cost factors related to SDLC processes. The model determines the optimal software development or V&V quality that gives the minimum value of an objective function which includes three risk-cost factors: 1) software quality control cost; 2) software defect fixing cost; and 3) the cost from NPP accident consequence considering software failure probability. We present a case study using OPR-1000 plant model. The study results showed important SDLC phases where the risk-cost factors can be minimized by achieving high software quality. The proposed method is expected to be useful to software developers and decision makers for assisting NPP software project and quantifying risk from software life cycle on NPP safety.