• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1658-1663
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• 2021

Research on climate change and global warming on the power generation systems are rapidly increasing because of the Importance of the sustainable energy supply, thus the electricity supply since its growing share, in the end, uses energy supply. However, some researchers conducted this field, but many research gaps are not mentioned and filled in this field's literature since the lack of general statements and the quantitative models and formulation of the issue. In this research, an exergy-based model is implemented to model a set of six power generation technologies (combined cycle, gas turbine, nuclear plant, solar PV, and wind turbine) and use this model to simulate each technology's responses to climate change impacts. Finally, using these responses to define and calculate a formulation for the relationship between the system's energy performance in different environmental situations and a dimensionless index to quantize each power technology's reliability against the climate change impacts called the Pahlev reliability index (P-index) of the power technology. The results have shown that solar and nuclear technologies are the most, and wind turbines are the least reliable power generation technologies.

• Nuclear Engineering and Technology
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• v.37 no.2
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• pp.127-138
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• 2005

Approaches to several recent issues in the operation of nuclear power plants using computational intelligence are discussed. These issues include 1) noise analysis techniques, 2) on-line monitoring and sensor validation, 3) regularization of ill-posed surveillance and diagnostic measurements, 4) transient identification, 5) artificial intelligence-based core monitoring and diagnostic system, 6) continuous efficiency improvement of nuclear power plants, and 7) autonomous anticipatory control and intelligent-agents. Several changes to the focus of Computational Intelligence in Nuclear Engineering have occurred in the past few years. With earlier activities focusing on the development of condition monitoring and diagnostic techniques for current nuclear power plants, recent activities have focused on the implementation of those methods and the development of methods for next generation plants and space reactors. These advanced techniques are expected to become increasingly important as current generation nuclear power plants have their licenses extended to 60 years and next generation reactors are being designed to operate for extended fuel cycles (up to 25 years), with less operator oversight, and especially for nuclear plants operating in severe environments such as space or ice-bound locations.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.838-843
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• 1998

Risk importance measures are widely wed to rank risk contributors in risk-based applications. Typically, Fussell-Vesely (F-V) importance and risk achievement worth (RAW) are used in the component importance raking for the reliability centered maintenance (RCM) analysis of safety system in nuclear power plants (NPPs). This study was performed as part of feasibility study on RCM for domestic NPPs, which is focused on the component importance ranking approach the maintenance recommendation. The approach of modulizing faulting tree basic events was applied in the simplification process of the PSA model and the validity of the approach was evaluated As a result of the case study, this paper included the importance and the maintenance recommendations for the safety-related equipments associated with safety injection and containment spray in large loss of coolant accident sequences.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.223-225
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• 2005

This paper will be introduce a new paradigm and prospects for energy supply system in near future which produces electric and district heat cogeneration with dispersed power grid with small nuclear power units. Recently, in nuclear field, a lot of effort has been done in nuclear major countries to develop small and medium reactor for enhancement of nuclear peaceful use as like in district heating, electric power generation, seawater desalination or hydrogen generation. This paper presents a new way and prospects for power source in distribution system by using the distributed & remote cogeneration system using small reactor.

• Environmental and Resource Economics Review
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• v.24 no.4
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• pp.629-655
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• 2015

Nuclear power generation is a major power source which accounts for more than 30% of domestic electricity generation. Electricity market needs to secure stability of base load. This study aimed at analyzing relationships between nuclear power generation and wholesale electricity price (SMP: System Marginal Price) in Korea. For this we conducted ARDL(Autoregressive Distributed Lag) approach and Granger causality test. We found that in terms of total effects nuclear power supply had a positive relationship with SMP while nuclear capacity had a negative relationship with SMP. There is a unidirectional Granger causality from nuclear power supply to SMP while the reverse was not. Nuclear power is closely related to SMP and provides useful information for decision making.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.321-328
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• 1998

A controller and sensor fault tolerant system jot a steam generator is designed with fuzzy logic. A structure of the : proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controlled and a sensor induced performances to identify Which Part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a charge in error of the system output an chosen as fuzzy variables. The fuzzy logic jot a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency, Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the : proposed fault tolerant control scheme jot a steam generator regulates welt water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even mote.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.887-892
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• 1998

A risk informed approach to relax AOTs and STIs of RPS/ESPAS in technical specifications of kori units 3, 4 was performed in this paper. With the proposed AOTs and STIs, system unavailabilities and core damage frequency were quantified using PSA model. The results shoe that core damage frequency is slightly increased by extending AOTs and STIs but negligible. As considering the benefits such as reduction of plant transients and man power for test and maintenance, the relaxation of AOTs/STIs of RPS/ESFAS is justified

• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.107-115
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• 2020

This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.36-40
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• 2019

In this study, we compared the operational rates of natural gas, coal, nuclear power and renewable energy based on the data of power generation and power generation facilities produced in summer season(from June to August) during the last four years(2015~2018). Nuclear power and coal power, which are responsible for basic power generation, were guaranteed to be economical as the actual generation capacity remained 60% higher than the cost of power generation. On the other hand, natural gas generation and new renewable energy generation have a very low actual operation rate of 29.5% and 27.3% compared to investments in power generation facilities, making it difficult to lower the cost of power generation. However, coal generation has structural problems in terms of greenhouse gas, fine dust. On the other hand, natural gas generation is relatively low and even though it is safe, it is difficult to secure economic feasibility as it is bound by a peak power system. Therefore, it is only possible to achieve balanced development of energy sources when there is a change in the development policy.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2883-2897
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• 2022

According to the Renewable Energy 3020 Implementation Plan announced in 2017 by the South Korean government, the electricity share of renewable energy will be expanded to 20% of the total electricity generation by 2030. Given the intermittency of electricity generation from renewable energy, realization of such a plan presents challenges to managing South Korea's isolated national electric grid and implies potentially large excess electricity generation in certain situations. The purpose of this study is: 1) to develop a model to accurately simulate the effects of excess electricity generation from renewables which would arise during the transition, and 2) to propose strategies to manage excess electricity generation through effective utilization of domestic electricity generating capabilities. Our results show that in periods of greater PV and wind power, namely the spring and fall seasons, the frequency of excess electricity generation increases, while electricity demand decreases. This being the case, flexible operation of coal and nuclear power plants along with LNG and pumped-storage hydroelectricity can be used to counterbalance the excess electricity generation from renewables. In addition, nuclear energy plays an important role in reducing CO₂ emissions and electricity costs unlike the fossil fuel-based generation sources outlined in the 8th Basic Plan.