Design of a Platform for Safety Justification of Safety-Critical Software

Since safety-critical software is crucial to nuclear safety in the occurrence of accident, it is required to have rather higher requirements in both reliability and safety than the non-safety one. However, since the complexity of a software product, how to ensure the reliability and safety of a software product is still a challenging work. The paper presents a design of a platform for safety justification of safety-critical software of nuclear power plants. A syllogism referred as to Claim, Argument and Evidence (CAE) is applied to clarify the key factors that will affect software reliability and the dependencies between them. The proposed safety justification platform offers a user-friendly graphical interface to help construct a CAE model by a drag and drop way. The proposed safety justification platform could be used for the rigorous argument of various factors that may affect the reliability of a safety-critical software product during different phases of its life cycle and establishing their causalities. In this way, it could greatly improve its creditability and applicability and lowering the uncertainties in software development and application, and therefore has a significant engineering values in ensuring and improving the quality and reliability of nuclear software products.