• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.38-41
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• 2007

The increase of $CO_2$ emission by increasing of fossil fuel usage has been understood a major cause of global warming. The supply of electric energy is heavily dependent on the massive thermal power and nuclear power plant before developing the renewable energy to supply the electric energy stably at a low price. The large and sound forged components of pressure vessel, turbine and generator are widely used in power plant such as wind power, hydroelectric power generation, nuclear power and thermal power plant. This paper is discussed the trend of manufacturing technology for pressure vessel and turbine to satisfy the required condition of utility company. It is also introduced a strategy of forging industry to cope with carbon tax.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.8-12
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• 2011

For reducing greenhouse gas emissions, the short-term strategy is of existing energy-efficient appliances to facilitate the spread of energy efficiency improvements to improve energy efficiency, energy saving projects that will include investments to enable. R&D is at the core of the long-term strategy. To reduce energy demand, the equipments and processes improved energy efficiency should be developed. In terms of energy supply, the policies for greenhouse gas reduction is to replace fossil fuels by expanding the supply of renewable energy such as solar, wind, geothermal, biomass and nuclear power as nearly zero-emission of greenhouse gas. In terms of energy consumption, measures to reduce greenhouse gas emissions is in line with the policy for efficiency improvement. The buildings & work-site of high-energy consumption in the building & Industry sectors, should implement a policy to strengthening the voluntary agreement on energy-saving facilities and expand to invest in energy saving facilities.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3581-3590
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• 2023

High-temperature design evaluations were conducted on Type 316L stainless steel piping for a 700 ℃ large-capacity thermal energy storage verification test loop (TESET) under construction at KAERI. The hot leg piping with sodium coolant at 700 ℃ connects the main components of the loop heater, hot storage tank, and air-to-sodium heat exchanger. Currently, the design rules of ASME B31.1 and RCC-MRx provide design procedures for high-temperature piping in the creep range for Type 316L stainless steel. However, the design material properties around 700 ℃ are not available in those rules. Therefore, a number of material tests, including creep tests at various temperatures, were conducted to determine the insufficient material properties and relevant design coefficients so that high-temperature design on the 700 ℃ piping may be possible. It was shown that Type 316L stainless steel can be used in a 700 ℃ high-temperature piping system of Generation IV reactor systems or a renewable energy systems, such as thermal energy storage systems, for a limited operation time.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.865-885
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• 2022

Korean government updated her Nationally Determined Contribution (NDC) in 2021 and announced the target and various measures for reductions. Among the many issues, final energy demand and renewable energy power mix for 17 provinces to achieve the target are being analyzed using GCAM-Korea. Simulation results show that final energy demand of 2030 is approximated at the similar level to that of 2018. This is being enabled by the conservation of coal with higher electrification especially in industry sector. Higher power demand with lower coal consumption in final energy consumption is shown to be provided by 33.1% of renewable, 24.6% of gas, and 18.0% of nuclear power generation in 2030. Meanwhile, the share of coal-fired power generation is expected to be reduced to 12.8%. Major future power provider becomes Gyeongbuk (Nuclear), Gyeonggi (Gas), Jeonnam (Nuclear, Gas) and Gangwon (PV, Wind), compared to one of current major power provider Chungnam (Coal). This analysis is expected to provide a useful insight toward the national and provincial energy and climate change policy.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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• pp.51-58
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• 2007

Gas hydrate is a special kind of inclusion compound that can be formed by capturing gas molecules to water lattice in high pressure and low temperature conditions. When referred to standard conditions, $1m^3$ solid hydrates contain up to $172Nm^3$ of methane gas, depending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming methane hydrate were theoretically obtained in aqueous single electrolyte solution containing 3wt% NaCl. The results show that the predictions match the previous experimental values very well, and it was found that NaCl acts as an inhibitor.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1472-1479
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• 2024

Cyber-Physical Energy Systems (CPESs) integrate cyber and hardware components to ensure a reliable and safe physical power production and supply. Renewable Energy Sources (RESs) add uncertainty to energy demand that can be dealt with flexible operation (e.g., load-following) of CPES; at the same time, scenarios that could result in severe consequences due to both component stochastic failures and aging of the cyber system of CPES (commonly overlooked) must be accounted for Operation & Maintenance (O&M) planning. In this paper, we make use of Deep Reinforcement Learning (DRL) to search for the optimal O&M strategy that, not only considers the actual system hardware components health conditions and their Remaining Useful Life (RUL), but also the possible accident scenarios caused by the failures and the aging of the hardware and the cyber components, respectively. The novelty of the work lies in embedding the cyber aging model into the CPES model of production planning and failure process; this model is used to help the RL agent, trained with Proximal Policy Optimization (PPO) and Imitation Learning (IL), finding the proper rejuvenation timing for the cyber system accounting for the uncertainty of the cyber system aging process. An application is provided, with regards to the Advanced Lead-cooled Fast Reactor European Demonstrator (ALFRED).

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.723-726
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• 2009

As a preliminary study of cost estimates for nuclear hydrogen systems, the hydrogen production costs of the nuclear energy sources benchmarking GT-MHR are estimated in the necessary input data on a Korean specific basis. G4-ECONS developed by EMWG of GIF in 2008 was appropriately modified to calculate the cost for hydrogen production of SI process with VHTR as a thermal energy source rather than the LUEC. The estimated costs presented in this paper show that hydrogen production by the VHTR could be competitive with current techniques of hydrogen production from fossil fuels if $CO_2$ capture and sequestration is required. Nuclear production of hydrogen would allow large-scale production of hydrogen at economic prices while avoiding the release of $CO_2$. Nuclear production of hydrogen could thus become the enabling technology for the hydrogen economy. The major factors that would affect the cost of hydrogen were also discussed.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.1-15
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• 2020

Nuclear power plants in South Korea are operated to cover the baseload demand. Hence they are operated at 100% rated power and do not deploy power tracking control except for startup, shutdown, or during transients. However, as the contribution of renewable energy in the energy mix increases, load follow operation may be needed to cover the imbalance between consumption and production due to the intermittent nature of electricity produced from the conversion of wind or solar energy. Load follow operation may be quite challenging since the operators need to control the axial power distribution and core reactivity while simultaneously conducting the power maneuvering. In this paper, a systems engineering approach for multi-physics load follow simulation of APR1400 is performed. RELAP5/SCDAPSIM/MOD3.4/3DKIN multi-physics package is selected to simulate the Korean Advanced Power Reactor, APR1400, under load follow operation to reflect the impact of feedback signals on the system safety parameters. Furthermore, the systems engineering approach is adopted to identify the requirements, functions, and physical architecture to provide a set of verification and validation activities that guide this project development by linking each requirement to a validation or verification test with predefined success criteria.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.248-257
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• 2020

This study presents an initial design for a novel system consisting in a coupled nuclear reactor and a phase change material-based thermal energy storage (TES) component, which acts as a buffer and regulator of heat transfer between the primary and secondary loops. The goal of this concept is to enhance the capacity factor of nuclear power plants (NPPs) in the case of high integration of renewable energy sources into the electric grid. Hence, this system could support in elevating the economics of NPPs in current competitive markets, especially with subsidized solar and wind energy sources, and relatively low oil and gas prices. Furthermore, utilizing a prismatic-core advanced high temperature reactor (PAHTR) cooled by a molten salt with a high melting point, have the potential in increasing the system efficiency due to its high operating temperature, and providing the baseline requirements for coupling other process heat applications. The present research studies the neutronics and thermal hydraulics (TH) of the PAHTR as well as TH calculations for the TES which consists of 300 blocks with a total heat storage capacity of 150 MWd. SERPENT Monte Carlo and MCNP5 codes carried out the neutronics analysis of the PAHTR which is sized to have a 5-year refueling cycle and rated power of 300 MW_th. The PAHTR has 10 metric tons of heavy metal with 19.75 wt% enriched UO₂ TRISO fuel, a hot clean excess reactivity and shutdown margin of $33.70 and -$115.68; respectively, negative temperature feedback coefficients, and an axial flux peaking factor of 1.68. Star-CCM + code predicted the correct convective heat transfer coefficient variations for both the reactor and the storage. TH analysis results show that the flow in the primary loop (in the reactor and TES) remains in the developing mixed convection regime while it reaches a fully developed flow in the secondary loop.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3054-3070
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• 2023

Nuclear Power Plants (NPP) are widely utilized around the globe from different base forms as it is one of the most dependable renewable resources that technological advancements have offered. However, different perceptions of the usage of NPPs emerged from different generations. The purpose of this study was to investigate the acceptance of nuclear energy as an alternative source of energy among Generation Z in the Philippines by utilizing an extended Theory of Planned Behavior (TPB) approach. An online questionnaire which consisted of 31 items was distributed using a purposive sampling approach and 450 respondents of Generation Z voluntarily answered. Structural Equation Modeling (SEM) showed that the knowledge regarding NPP had significant effects on risk perception and benefit perception which subsequently led to subjective norms. In addition, perceived behavioral control and subjective norms had significant effects on behavioral intention which led to nuclear acceptance. Interestingly, the respondents perceived the benefit of NPP as slightly higher than the perceived risk. With these, it was clear that the commissioning Nuclear Power Plant must consider as an alternative source of electric energy in the Philippines. Moreover, this study is one of the first studies that investigated the acceptance of NPP among Generation Z. Lastly, the model could be a basis to strengthen the acceptance strategy of opening NPP among Generation Z, particularly in developing countries.