• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3732-3744
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• 2022

To investigate the effects of ocean conditions on the thermal stress and deformation caused by thermal stratification of a pressurizer surge line in a floating nuclear power plant (FNPP), the finite element simulation platform ANSYS Workbench is utilized to conduct the fluid-solid-thermal coupling transient analysis of the surge line under normal "wave-out" condition (no motion) and under ocean conditions (rolling and pitching), generating the transient response characteristics of temperature distribution, thermal stress and thermal deformation inside the surge line. By comparing the calculated results for the three motion conditions, it is found that ocean conditions can significantly improve the thermal stratification phenomenon within the surge line, but may also result in periodic oscillations in the temperature, thermal stress, and thermal deformation of the surge line. Parts of the surge line that are more susceptible to thermal fatigue damage or failure are determined. According to calculation results, the improvements are recommended for pipeline structure to reduce the effects of thermal oscillation caused by ocean conditions. The analysis method used in this study is beneficial for designing and optimizing the pipeline structure of a floating nuclear power plant, as well as for increasing its safety.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.37-48
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• 2021

Improving the plant protection system against unforeseen changes/transients during operation is essential to maintain plant safety. Under this condition, it requires rapid and accurate signal processing. The use of an Intellectual Property (IP) core for floating point calculations for Safety Critical MMIS can make numerical computations easier and more precise, improving system accuracy. It can represent and manipulate rational numbers as well as a much broader range of values with dynamic range in nuclear power plant. Systems engineering approach (SE) is used through the development process, it helps to reduce complexity and avoid omissions and invalid assumptions as delivers a better understanding of the stakeholders needs. For the implementation on the FPGA target board, the 32-bit floating-point arithmetic with IEEE-754 standards has designed using Simulink model in Matlab for all operations of addition, subtraction, multiplication and division and VHDL code generated.

• Earthquakes and Structures
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• v.14 no.1
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• pp.33-44
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• 2018

Base-isolated nuclear power plant (BI-NPP) structures are founded on expanded basemat as a flexible floating nuclear island, are still lacking the recommendation of the consideration of incoherent motion effect. The effect of incoherent earthquake motion on the seismic response of BI-NPP structure has been investigated herein. The incoherency of the ground motions is applied by using an isotropic frequency-dependent spatial correlation function to perform the conditional simulation of the reference design spectrum compatible ground motion in time domain. Time history analysis of two structural models with 486 and 5 equivalent lead plug rubber bearing (LRB) base-isolators have been done under uniform excitation and multiple point excitation. two different cases have been considered: 1) Incoherent motion generated for soft soil and 2) Incoherent motion generated for hard rock soil. The results show that the incoherent motions reduce acceleration and the lateral displacement responses and the reduction is noticeable at soft soil site and higher frequencies.

• New & Renewable Energy
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• v.9 no.4
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• pp.25-31
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• 2013

This paper describes an electrical linear generator (IntELG) based on permanent magnets, containing heaving buoy, and its applications for the floating wave energy converters riding in parallel waves. The permanent magnets are integrated with the heaving buoy as a component and the integrated component is configured within the cylindrical IntELG to be filled with fluid. Thus, the IntELG can effectively be applied for the power-take-off of the floating wave energy converter riding in parallel waves. Typical applications are exampled with the Pelamis and Anaconda and they are investigated for the diversely redundant power source of nuclear power plant and the cooperation with submerged tunnel(s).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1233-1234
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• 2011

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.35-44
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• 2018

Korea government aims to generate 20 percent of its electricity with clean, renewable energy by 2030, while reducing its reliance on fossil fuel and nuclear power plants. Technically, solar energy has resource potential that far exceeds the entire global energy demand. Solar energy industry has experienced phenomenal growth in recent years due to both technological improvements resulting in cost reductions and government policies for renewable energy development and utilization. Even though solar power generation has several advantages over other forms of electricity generation, the major problem is the requirement of land which is scarcely available in the local site and its cost. This study analyzes the available capacity of landing and floating solar plants for the case of chonnam province in korea. The results of design capacity show about 7.5GW for landing and 1.5GW for floating solar power plant. Also, with a purpose to comprehend intention-behaviour gap about acceptance of solar community, the solutions are suggested.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.5
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• pp.499-505
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• 2024

To address the issue of global warming, various regulations and policies for reducing greenhouse gas emissions are being implemented. In this context, the number of countries targeting carbon neutrality, the latter of which entails reducing net carbon emissions to zero, is increasing, and small modular reactors (SMRs) are investigated extensively as a new model for power plants. SMRs, although measuring only 5%-10% of the size of conventional large nuclear power plants, are highly efficient systems that can generate hundreds of megawatts of power. Compared with fossil fuel-based power plants, SMRs generate less carbon emissions and can complement the unstable energy supply from renewable sources. However, the use of SMRs is opposed by local residents owing to the risk of significant radioactive-material leakage when a nuclear-power-plant accident occurs. Hence, floating, small nuclear-power vessels are being investigated and installed in the ocean, thus simplifying the process of securing land, compensating nearby residents, and increasing safety against natural disasters. In this study, the towing stability of SMR power ships is analyzed, and the result shows no significant risk of towing to the destination in sea states 3, 4, and 5.

• Structural Engineering and Mechanics
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• v.76 no.3
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• pp.367-378
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• 2020

This paper presents a new design concept for ocean nuclear power plants (ONPPs) using a tension leg platform (TLP). The system-integrated modular advanced reactor, which is one of the successful small modular reactors, is mounted for demonstration. The authors define the design requirements and parameters, modularize and rearrange the nuclear and other facilities, and propose a new total general arrangement. The most fundamental level of design results for the platform and tendon system are provided, and the construction procedure and safety features are discussed. The integrated passive safety system developed for the gravity based structure-type ONPP is also available in the TLP-type ONPP with minor modifications. The safety system fully utilizes the benefits of the ocean environment, and enhances the safety features of the proposed concept. For the verification of the design concept, hydrodynamic analyses are performed using the commercial software ANSYS AQWA with the Pierson-Moskowitz and JONSWAP wave spectra that represent various ocean environments and the results are discussed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.3
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• pp.120-124
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• 1998

The present study was initiated to protect floating nuclear power plants from the tornado. The solution shows that a tonado induces extreme waves of 27 ft (8.2 m) in height if it crosses the basin with a speed close to the critical speed. Waves generated by wind stress are ignored.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1738-1748
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• 2019

Previous research has shown that the inclined condition has an impact on the natural circulation (natural circulation) mode operation of Floating Nuclear Power Plant (FNPP) mounted on the movable marine platform. Due to its compact structure, small volume, strong maneuverability, the Integral Pressurized Water Reactor (IPWR) is adopted as marine reactor in general. The OTSGs of IPWR are symmetrically arranged in the annular region between the reactor vessel and core support barrel in this paper. Therefore, many parallel natural circulation loops are built between the core and the OTSGs primary side when the main pump is stopped. and the inclined condition would lead to discrepancies of the natural circulation drive head among the OTSGs in different locations. In addition, the flow rate and temperature nonuniform distribution of the core caused by inclined condition are coupled with the thermal hydraulics parameters maldistribution caused by OTSG group operating mode on low power operation. By means of the RELAP5 codes were modified by adding module calculating the effect of inclined, heaving and rolling condition, the simulation model of IPWR in inclined condition was built. Using the models developed, the influences on natural circulation operation by inclined angle and OTSG position, the transitions between forced circulation (forced circulation) and natural circulation and the effect on natural circulation operation by different OTSG grouping situations in inclined condition were analyzed. It was observed that a larger inclined angle results the temperature of the core outlet is too high and the OTSG superheat steam is insufficient in natural circulation mode operation. In general, the inclined angle is smaller unless the hull is destroyed seriously or the platform overturn in the ocean. In consequence, the results indicated that the IPWR in the movable marine platform in natural circulation mode operation is safety. Selecting an appropriate average temperature setting value or operating the uplifted OTSG group individually is able to reduce the influence on natural circulation flow of IPWR by inclined condition.