KINAC has regulated cyber security of nuclear facilities based on「Act on Physical Protection and Radiological Emergency」and KINAC/RS-015 “Security for Computer and Information System of Nuclear Facilities”, a regulatory guide. By that law and regulatory guide, nuclear licensees shall protect digital assets so-called CDAs, which are conducting safety, security, and emergency preparedness functions from cyber-attack. First of all, to protect CDAs from cyber-attack, licensees should identify CDAs from their assets according to the RS-015. The identification methods are provided in another regulatory guide, RS-019. To research the best practice, a reference case is selected as a U.S. case. In this study, a comparison analysis was conducted especially focused on EP CDAs identification methodology between R.O.K. and U.S., because the regulation basis is relatively insufficient in R.O.K., and improvement plans for the cyber security regulations in R.O.K were proposed. From the analysis, it was identified that detailed methods to identify EP function are provided in NEI 10-14 “Identifying Systems and Assets Subject to the Cyber Security Rule” published by Nuclear Energy Institute (NEI), an institute of nuclear power reactor licensees. Also identified that the definition of EP function is provided clearly in NEI 10-04 based on related regulation, 10 CFR 50.47 “Emergency Plans”. In that regulation, licensees shall follow and maintain the effectiveness of an emergency plan that meets the sixteen planning standards of 10 CFR 50.47(b). So, these sixteen planning standards correspond to the emergency preparedness functions. In NEI 10-04, scoping considerations for emergency preparedness function are provided referring to sixteen planning standards. Moreover, in that scoping considerations, planning standards, planning standard functions and 10 CFR 73.54 “Protection of digital computer and communication systems and networks” scoping guidance are provided, so, licensees identify EP CDA in their assets conveniently. In case of R.O.K., because these sixteen planning standards are not established, there is an ambiguity in identifying EP CDAs. The only related provision is “Detailed Standards for Establishment of Emergency Plan”. To resolve the ambiguity, it is needed to analyze sixteen planning standards in 10 CFR 50.47(b) and “Detailed Standards for Establishment of Emergency Plan”. Then, should be developed ‘scoping considerations for emergency preparedness function’ based on the analysis as provided in NEI 10-04.

The crisis of climate change aroused international needs to reduce the greenhouse gas emission in energy sector. Government of South Korea formulated an agenda of carbon neutrality through announcing 2050 Net-Zero Carbon Scenario A and B in October 2021. As the power supply from renewable energy increases, it becomes a core element to take into account the daily intermittency of renewable energy in analyzing the upcoming energy plans. However, the existing yearly Load Duration Curve is insufficient for applying day and night power change in daily scale into energy mix analysis, since it derives the energy mix for whole year on the basis of classifying annual base load and peak load. Therefore, a new energy mix simulation model based on the daily power load and supply simulation is needed for the future energy analysis. In this study we developed a new model which simulates the average power supply and demand daily (over a 24 hour period) for each season. The model calculates the excess and shortage power during day and night by integrating each energy’s daily power pattern. The 2050 Net-Zero Carbon Scenario A was used for the model verification, during which the same amounts of power production from each energy source were applied: nuclear, renewable, carbon-free gas turbine, fuel cell and byproduct gas. Total power demand pattern and renewable energy production pattern were drawn from the data of 2017 power production, and Pumped-storage Hydroelectricity and Energy Storage System were used as day-to-night conversion. Detailed assumptions for each energy were based on the Basis of Calculation for Net-Zero Carbon Scenario from Government. The model was verified with three cases which were divided depending on the method of hydrogen production and whether the Curtailment and Conversion Loss (CCL) of renewable energy were considered or not. Case 1 assumed production of hydrogen occurred for 24 hours while not considering CCL, had 0% relative error in comparison of total annual power production, and case 2, considering CCL, had a 1.741% relative error. Case 3 assumed production of hydrogen occurred only during daytime with excess power and CCL consideration, yielded 0.493% relative error in total amount of hydrogen production, confirming that the model sufficiently describes the Government’s Scenario A with the input of total power production. This model is expected to be used for analyzing further energy mix with different ratios of each energy source, with special focus on nuclear and renewable energy sources.