• Advances in Energy Research
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• 제3권2호
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• pp.71-80
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• 2015

This paper describes nuclear energy technologies for the solution of long term energy problem with better reliability. A short overview about nuclear energy applications are explained with a basic analysis of energy. Furthermore, industrial application, space application of nuclear systems and ship propulsion in nuclear energy application are demonstrated in more detail. This report also includes some examples of the experienced nuclear power plant to identify energy production. The general purpose of the article is to understand how efficiently nuclear systems generates energy, and solve the world's increasing energy demand in our century.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2315-2324
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• 2023

Space nuclear reactors are becoming popular in deep space exploration owing to their advantages of high-power density and stability. Following the fourth-generation nuclear reactor technology, a conceptual design of the dual drum-controlled space molten salt reactor (D²-SMSR) is proposed. The reactor concept uses molten salt as fuel and heat pipes for cooling. A new reactivity control strategy that combines control drums and safety drums was adopted. Critical physical characteristics such as neutron energy spectrum, neutron flux distribution, power distribution and burnup depth were calculated. Flow and heat transfer characteristics such as natural convection, velocity and temperature distribution of the D²-SMSR under low gravity conditions were analyzed. The reactivity control effect of the dual-drums strategy was evaluated. Results showed that the D²-SMSR with a fast spectrum could operate for 10 years at the full power of 40 kWth. The D²-SMSR has a high heat transfer coefficient between molten salt and heat pipe, which means that the core has a good heat-exchange performance. The new reactivity control strategy can achieve shutdown with one safety drum or three control drums, ensuring high-security standards. The present study can provide a theoretical reference for the design of space nuclear reactors.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3039-3045
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• 2023

Fiber-reinforced polymer (FRP) composites are considered suitable candidates for structural materials of spacecrafts due to their excellent properties of high strength, light weight, and corrosion resistance. An online health monitoring method for FRP composites must be applied to space structures. However, the application of existing health monitoring methods to space structures is limited due to the harsh space environment. Here, carbon fiber-reinforced polymer (CFRP) composites embedded with fiber Bragg grating (FBG) sensors were prepared to explore the feasibility of strain monitoring using embedded FBG sensors in γ-radiation environment. The analysis of the influence of radiation on the strain monitoring demonstrated that the embedded FBG can be successfully applied to the health monitoring of FRP composites in radiation environment.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.678-699
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• 2015

Although the harsh space environment imposes many severe challenges to space pioneers, space exploration is a realistic and profitable goal for long-term humanity survival. One of the viable and promising options to overcome the harsh environment of space is nuclear propulsion. Particularly, the Nuclear Thermal Rocket (NTR) is a leading candidate for nearterm human missions to Mars and beyond due to its relatively high thrust and efficiency. Traditional NTR designs use typically high power reactors with fast or epithermal neutron spectrums to simplify core design and to maximize thrust. In parallel there are a series of new NTR designs with lower thrust and higher efficiency, designed to enhance mission versatility and safety through the use of redundant engines (when used in a clustered engine arrangement) for future commercialization. This paper proposes a new NTR design of the second design philosophy, Korea Advanced NUclear Thermal Engine Rocket (KANUTER), for future space applications. The KANUTER consists of an Extremely High Temperature Gas cooled Reactor (EHTGR) utilizing hydrogen propellant, a propulsion system, and an optional electricity generation system to provide propulsion as well as electricity generation. The innovatively small engine has the characteristics of high efficiency, being compact and lightweight, and bimodal capability. The notable characteristics result from the moderated EHTGR design, uniquely utilizing the integrated fuel element with an ultra heat-resistant carbide fuel, an efficient metal hydride moderator, protectively cooling channels and an individual pressure tube in an all-in-one package. The EHTGR can be bimodally operated in a propulsion mode of $100MW_{th}$ and an electricity generation mode of $100MW_{th}$, equipped with a dynamic energy conversion system. To investigate the design features of the new reactor and to estimate referential engine performance, a preliminary design study in terms of neutronics and thermohydraulics was carried out. The result indicates that the innovative design has great potential for high propellant efficiency and thrust-to-weight of engine ratio, compared with the existing NTR designs. However, the build-up of fission products in fuel has a significant impact on the bimodal operation of the moderated reactor such as xenon-induced dead time. This issue can be overcome by building in excess reactivity and control margin for the reactor design.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1660-1668
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• 2017

The flow of liquids submerged with nanoparticles is of significance to industrial applications, specifically in nuclear reactors and the cooling of nuclear systems to improve energy efficiency. The application of nanofluids in water-cooled nuclear systems can result in a significant improvement of their economic performance and/or safety margins. Therefore, in this paper, Marangoni thermal convective boundary layer dusty nanoliquid flow across a flat surface in the presence of solar radiation is studied. A two phase dusty liquid model is considered. Unlike classical temperature-dependent heat source effects, an exponential space-dependent heat source aspect is considered. Stretching variables are utilized to transform the prevailing partial differential system into a nonlinear ordinary differential system, which is then solved numerically via the Runge-Kutta-Fehlberg approach coupled with a shooting technique. The roles of physical parameters are focused in momentum and heat transport distributions. Graphical illustrations are also used to consider local and average Nusselt numbers. We examined the results under both linear and quadratic variation of the surface temperature. Our simulations established that the impact of Marangoni flow is useful for an enhancement of the heat transfer rate.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1589-1599
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• 2017

Field programmable gate arrays (FPGAs) are getting more attention in safety-related and safety-critical application development of nuclear power plant instrumentation and control systems. The high logic density and advancements in architectural features make static random access memory (SRAM)-based FPGAs suitable for complex design implementations. Devices deployed in the nuclear environment face radiation particle strike that causes transient and permanent failures. The major reasons for failures are total ionization dose effects, displacement damage dose effects, and single event effects. Different from the case of space applications, soft errors are the major concern in terrestrial applications. In this article, a review of radiation effects on FPGAs is presented, especially soft errors in SRAM-based FPGAs. Single event upset (SEU) shows a high probability of error in the dependable application development in FPGAs. This survey covers the main sources of radiation and its effects on FPGAs, with emphasis on SEUs as well as on the measurement of radiation upset sensitivity and irradiation experimental results at various facilities. This article also presents a comparison between the major SEU mitigation techniques in the configuration memory and user logics of SRAM-based FPGAs.

• 항공우주정책ㆍ법학회지
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• 제22권1호
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• pp.29-54
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• 2007

우주활동이 환경과 관련되어 문제가 되는 것은 우주의 탐사활동과 이용을 통해 우주공간이나 천체 및 지구의 환경이 현저하게 오염될 수 있기 때문이다. 특히 우주에서 핵연료(Nuclear Power Sources; 약칭하여 'NPS')를 사용하는 위성이나 우주물체가 기능부전(malfunction)으로 인하여 지구에 재진입하면서 추락했을 경우, 그에 따른 재앙은 실로 엄청날 것이다. 1961년 미국에서 원자력 발전기에 의한 인공위성을 쏘아 올린 이래 원자로를 핵연료로 이용한 원자력위성은 무수히 많다. 주로 달이나 혹성에 발사하는 위성이라든지 군사적인 목적을 띤 위성이 주로 이러한 위성들인데 이들이 우주공간에서 파괴되던가 또는 지표면에 충돌하는 경우에 발생하는 피해는 상당히 심각한 것으로 우려되고 있다. 본 논문은 이와 관련하여 대표적인 인공위성 추락사건인 1978년 소련의 핵원료 위성 Cosmos 954 사건과 이로 인해 UN내에서 '외기권 우주의 평화적 이용에 관한 위원회'(Committee on the Peaceful Uses of Outer Space : 약칭하여 'COPUOS')를 통해서 장기간 논의하다가 1992년 UN총회의 결의를 통해 채택된 "우주에서의 핵원료사용에 관한 원칙"(Principles Relevant to the Use of Nuclear Power Sources in Outer Space; 일명 'NPS원칙')의 내용과 그것의 우주법적 의미에 관하여 살펴보았다. 우주법으로서는 1967년 우주조약, 1968년 구조협정, 1972년 책임협약, 1976년 등록협약, 1979년 달조약의 관련조항을 들 수 있고, 그밖에 핵관련조약들과 국제환경법상 일반원칙들을 살펴보았다. NPS원칙과 같은 연성법은 조약과 같은 경성법에 비하여 효력면에서 구속력은 없으나 국가들이 점차 수용할 때 그것은 국제관습법이 될 수 있으며 국제관습법은 모든 국가를 구속한다는 점에서 그 의의를 찾을 수 있다. 예를 들어 1963 년 12윌 13 일 UN총회가 우주의 법적지위에 관하여 우주 활동을 규제하는 법원칙인 "외기권 우주의 탐사 및 이용에 관한 국가들의 활동을 규제하는 법원칙의 선언"(Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space)을 채택하였는데 이는 1967년 우주조약으로 발전하였다. 조약의 체결에도 불구하고 아직도 이 결의가 중요한 의미를 가지고 있는 것은 이 결의의 주요내용인 우주이용의 자유체제, 우주의 점령이나 주권주장을 통한 전유화 금지, 국제법의 준수, 국제책임, 우주비행사의 구조, 인류 전체의 이익지향 등의 원칙들이 국제관습법으로 발전하여 현재 우주관계법에 가입하지 않은 국가들도 구속하고 있다는 점이다.

• 항공우주정책ㆍ법학회지
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• 제spc호
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• pp.35-58
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• 2007

우주활동이 환경과 관련되어 문제가 되는 것은 우주의 탐사활동과 이용을 통해 우주공간이나 천체 및 지구의 환경이 현저하게 오염될 수 있기 때문이다. 특히 우주에서 핵연료(Nuclear Power Sources; 약칭하여 'NPS')를 사용하는 위성이나 우주물체가 기능부전(malfunction)으로 인하여 지구에 재진입하면서 추락했을 경우, 그에 따른 재앙은 실로 엄청날 것이다. 1961년 미국에서 원자력 발전기에 의한 인공위성을 쏘아 올린 이래 원자로를 핵연료로 이용한 원자력위성은 무수히 많다. 주로 달이나 혹성에 발사하는 위성이라든지 군사적인 목적을 띤 위성이 주로 이러한 위성들인데 이들이 우주공간에서 파괴되던가 또는 지표면에 충돌하는 경우에 발생하는 피해는 상당히 심각한 것으로 우려되고 있다. 본 논문은 이와 관련하여 대표적인 인공위성 추락사건인 1978년 소련의 핵원료 위성 Cosmos 954 사건과 이로 인해 UN내에서 '외기권 우주의 평화적 이용에 관한 위원회'(Committee on the Peaceful Uses of Outer Space : 약칭하여 'COPUOS')를 통해서 장기간 논의하다가 1992년 UN총회의 결의를 통해 채택된 "우주에서의 핵원료사용에 관한 원칙"(Principles Relevant to the Use of Nuclear Power Sources in Outer Space; 일명 'NPS원칙')의 내용과 그것의 우주법적 의미에 관하여 살펴보았다. 우주법으로서는 1967년 우주조약, 1968년 구조협정, 1972년 책임협약, 1976년 등록협약, 1979년 달조약의 관련조항을 들 수 있고, 그밖에 핵관련조약들과 국제환경법상 일반원칙들을 살펴보았다. NPS원칙과 같은 연성법은 조약과 같은 경성법에 비하여 효력면에서 구속력은 없으나 국가들이 점차 수용할 때 그것은 국제관습법이 될 수 있으며 국제관습법은 모든 국가를 구속한다는 점에서 그 의의를 찾을 수 있다. 예를 들어 1963 년 12윌 13 일 UN총회가 우주의 법적지위에 관하여 우주 활동을 규제하는 법원칙인 "외기권 우주의 탐사 및 이용에 관한 국가들의 활동을 규제하는 법원칙의 선언"(Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space)을 채택하였는데 이는 1967년 우주조약으로 발전하였다. 조약의 체결에도 불구하고 아직도 이 결의가 중요한 의미를 가지고 있는 것은 이 결의의 주요내용인 우주이용의 자유체제, 우주의 점령이나 주권주장을 통한 전유화 금지, 국제법의 준수, 국제책임, 우주비행사의 구조, 인류 전체의 이익지향 등의 원칙들이 국제관습법으로 발전하여 현재 우주관계법에 가입하지 않은 국가들도 구속하고 있다는 점이다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.224-225
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• 2019

Virtual reality technology can be defined as human-computer interface that makes virtual place of specific environments or situation is an interactive computer-generated experience taking place within a simulated environment. In order to combine virtual reality technology of domestic nuclear power industry, the R&D Project has been developing a virtual/augment reality system for nuclear power plant from April 2018 to March 2021. To effectively apply virtual reality technology of domestic nuclear industry, it is necessary to build virtual space similar to real environment. Therefore, This study is analysed 3d model status for nuclear power plant during the life-cycle, and suggested a method to build 3D cad model close to real environment.

• Nuclear Engineering and Technology
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• 제32권5호
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• pp.485-494
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• 2000

In this work, a fuzzy neural network is used to estimate the relevant sensor signal using other sensor signals. Noise components in input signals into the fuzzy neural network are removed through the wavelet denoising technique . Principal component analysis (PCA) is used to reduce the dimension of an input space without losing a significant amount of information. A lower dimensional input space will also usually reduce the time necessary to train a fuzzy-neural network. Also, the principal component analysis makes easy the selection of the input signals into the fuzzy neural network. The fuzzy neural network parameters are optimized by two learning methods. A genetic algorithm is used to optimize the antecedent parameters of the fuzzy neural network and a least-squares algorithm is used to solve the consequent parameters. The proposed algorithm was verified through the application to the pressurizer water level and the hot-leg flowrate measurements in pressurized water reactors.