The fusion DEMO program of Korea has been conceptualized to realize magnetic fusion energy with the tokamak concept at the end of 2030 s or early 2040 s. In this program, to expedite the development of a fusion DEMO plant, cross-cutting based on the commonalities between the fusion DEMO plant and existing systems. Among the existing systems, the current and generation IV nuclear power plants will have many areas of commonalities with the fusion DEMO plant including regulatory requirements and licensing processes, codes and standards, design methods and computational codes for thermo hydraulic analysis, and safety analysis methods. Theses commonalities will be used for discovering a pathway of resolving the nested logic dilemma incurred by the inherent first-of-a-kind nature of the fusion DEMO plant. This paper presents the result of an exploratory study on the subject cross-cutting.