In Korea, additional regulatory requirements are increasing due to the full-scale decommissioning of nuclear power plants following the permanent shutdown of Kori Unit 1 and Wolseong Unit 1. Accordingly, it is necessary to preemptively expand the scope of physical protection regulations from design, construction, and operation stage to back-end nuclear fuel cycle such as cessation of operation and decommissioning. According to Article 2, Paragraph 24 of the Nuclear Safety Act, the decommissioning of nuclear facilities is defined as all activities to exclude them from the application of the Nuclear Safety Act by permanently suspending the operation of nuclear facilities, demolishing the facilities and sites, or removing radioactive contamination. In other words, it refers to a series of technologies or activities to safely and efficiently dismantle nuclear power plant and remove radioactive contamination and restore them to their original state after permanently shut down of nuclear power plant. Security changes during decommissioning and decontamination since removing fuel from the reactor alters the plant’s safety status, some of the systems or components considered as vital equipment during plant operation will no longer be needed. The vital areas may be reduced as fewer buildings, equipment and systems need to be protected, which means access controls, surveillance and so on can be reduced. And also, decommissioning will probably require more workers than operation would, although this might not be the case at all times. From a security point of view, this might require more personnel or additional access points. Changing operating require changed security measures, to ensure that the required security level will be maintained while at the same time work proceeds efficiently. Once all of the fuel is removed from the plant, radiological release risk is much lower. The lower risk requires a lower level of security measures. Even during the removal of nuclear material and contaminated equipment from nuclear facilities, lower level of security measures should meet regulatory requirements based on a graded approach. Therefore, this study intends to examine the responsibilities and obligations of regulatory authorities, regulator, and nuclear operators in terms of protection after permanent shutdown and decommissioning.

• Minho Kang(Korea Institute of Nuclear Nonproliferation and Control (KINAC)) Corresponding author
• Sundo Choi(Korea Institute of Nuclear Nonproliferation and Control (KINAC))