The effectiveness of the present practice of introducing digital computers into the safety system of nuclear power plants in both Japan and Korea, has been reviewed referring an international guideline set by IAEA as the common basis for the discussion. The usefulness of the international guideline was ascertained for fostering ¡Çsafety culture¡Ç among the developers, regulators and plant operators, while the further research necessity was pointed out for enhancing software productivity with satisfying software reliability.