[en] The study of activities to solve software safety and quality must be executed in base of establishing software development process for digitalized nuclear plant. Especially study of software testing and verification and validation must executed. For this purpose methodologies and tools which can improve software qualities are evaluated and software testing and V and V which can be applied to software life cycle are investigated. This study establish a guideline that can assure software safety and reliability requirements in digitalized nuclear plant systems and can be used as a guidebook of software development process to assure software quality many software development organization