[en] Before May 17, 2005, Korea's nuclear power plant (hereinafter referred to as 'NNP') regulation system was two-pronged. Every NPP system consists of primary or secondary system, and each type was respectively regulated by the Atomic Energy Act(hereinafter referred to as 'AEA') and the Electric Utility Act(hereinafter referred to as 'EUA'). This unusual regulatory regime gave rise to a number of problems with respect to operation and safety. For this reason, the Enforcement Regulation of AEA and applicable Notice were revised on May 17, 2005 to the effect that all regulation on NPPs subject to EUA was brought under the purview of AEA, except regulation on business license for nuclear power generation under Article 7 of EUA and approval of plan of works for setting up electric installations (hereinafter referred to as 'construction plan') (including approval of any changes; the same shall apply hereinafter) under Article 61 thereof. From the point of view of the Ministry of Science and Technology, the regulation of NPPs by a single law has enhanced their safety. However, the Ministry of Commerce, Industry and Energy retains regulatory authority regarding NPPs. It reviews and approves construction plans for secondary system pursuant to Article 61 of EUA and Article 28 of the Enforcement Regulation thereof. This situation arose because Article 28 of the Enforcement Regulation of EUA continues to provide for matters related with nuclear power. Therefore, continued control of NPPs under EUA ignores the relationship and respective nature of AEA and EUA. There is also possibility of violation of a superseding law. Even if said provision is not in violation of a superseding law, Article 28 of the Enforcement Regulation of EUA poses the possibility of overlapping regulation, which may violate the principle of prohibiting excessive regulation, one of the principles of the Korean Constitution. Assessment of the dual regulatory system for review of secondary system requires (i) identifying problems by analyzing the nature of AEA and EUA and the regulatory law system on NPPs and (ii) ascertaining the legitimacy of the dual regulatory system according to the legal principles of the Constitution and administrative law