• Nuclear Engineering and Technology
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• 제52권2호
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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.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.457-463
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• 2005

현재 HIC는 차폐용기를 이용하여 소내 중간저장시설로 운반되고 있으나, 차폐용기가 국내 방사성폐기물 운반관련 규정에 부합하는지에 대한 논란이 있어왔다. 이에 따라 한국수력원자력(주)에서는 국내 규정 및 IAEA 규정을 만족하는 HIC 전용 운반용기 개발을 추진 중에 있으며, 원자력 환경기술원에서는 이를 위한 개념설계를 수행 중에 있다. 본 연구에서는 원전 현장에서 활용중인 방사성핵종분석 프로그램 자료와 Micro Shield 전산코드를 활용하여 법적기준을 만족하는 차폐체의 두께를 계산하고자 하였다. 차폐체는 구조적 안전성을 고려하여 탄소강으로 결정하였으며, 차폐체의 두께를 HIC 표면선량율 500 R/hr와 100 R/hr의 경우로 각각 나누어 계산하였다. 계산결과 표면선량율이 500 R/hr일 경우 차폐체의 두께가 22 cm, 표면선량율이 100 R/hr일 경우는 차폐체의 두께가 17 cm 일 때 법적 제한치를 만족 하는 것으로 평가 되었다.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.455-476
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• 2009

The history of nuclear fusion research in Korea is rather short compared to that of advanced countries. However, since the mid-1990s, at which time the construction of KSTAR was about to commence, fusion research in Korea has been actively carried out in a wide range of areas, from basic plasma physics to fusion reactor design. The flourishing of fusion research partly owes to the fact that industrial technologies in Korea including those related to the nuclear field have been fully matured, with their quality being highly ranked in the world. Successive pivotal programs such as KSTAR and ITER have provided diverse opportunities to address new scientific and technological problems in fusion as well as to draw young researchers into related fields. The frame of the Korean nuclear fusion program is now changing from a small laboratory scale to a large national agenda. Coordinated strategies from different views and a holistic approach are necessary in order to achieve optimal efficiency and effectiveness. Upon this background, the present paper reflects upon the road taken to arrive at this point and looks ahead at the coming future in nuclear fusion research activities in Korea.

• Nuclear Engineering and Technology
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• 제27권1호
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• pp.33-44
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• 1995

원자력 발전에 대한 국민수용성은 체르노빌 사고와 급격한 민주화 이후 한국의 원자력발전 프로그램에 큰 영향을 주게 되었다. 국민수용성 향상을 위한 여론 반영 방법은 첫째. 국민들의 원자력발전에 대한 인식을 이해하고 둘째, 그에 따른 정책 대안들에 대한 국민들의 선호도를 알아내는 것이라고 할 수 있다. 이를 위해 이 연구에서는 다섯 가지 발전방식에 대한 국민들의 인식패턴을 분석하기 위해 단순화된 다요 소효용모델을 적용하고, 12개의 안전성 항상 및 발전소주변지역 지원 정책 등에 대한 선호도를 측정하기 위해 컨조인트 분석 방법을 적용하여 보았다. 원자력발전소 방문 경험이 있는 특정인들을 대상으로 실제 우편 설문조사를 통하여 그들의 인식을 진단하고, 가능성 있는 정책대안들에 대한 선호도를 알아본 후 이로부터 각 정책의 효과를 예측하여 보았다. 이 결과와 이러한 분석 방법은 새로운 원자력 발전소 정책대안들에 대한 국민수용성을 알아보는데 유용할 것이다.

• Nuclear Engineering and Technology
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• 제40권4호
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• pp.255-268
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• 2008

The greater demand for electricity and the available capacity within safety margins in some operating NPPs are prompting nuclear utilities to request license modification to enable operation at a higher power level, beyond their original license provisions. Such plant modifications require an in-depth safety analysis to evaluate the possible safety impact. The analysis must consider the thermo hydraulic, radiological and structural aspects, and the plant behavior, while taking into account the capability of the structures, systems and components, and the reactor protection and safeguard systems set points. The purpose of this paper is to introduce international experiences and approaches for implementation of power uprates related to the reactor thermal power of nuclear power plants. The paper is intended to give the reader a general overview of the major processes, work products, issues, challenges, events, and experiences in the power uprates program. The process of increasing the licensed power level of a nuclear power plants is called a power uprate. One way of increasing the thermal output from a reactor is to increase the amount of fissile material in use. It is also possible to increase the core power by increasing the performance of the high power bundles. Safety margins can be maintained by either using fuels with a higher performance, or through the use of improved methods of analysis to demonstrate that the required margins are retained even at the higher power levels. The paper will review all types of power uprates, from small to large, and across various reactor types, including light and heavy water, pressurized, and boiling water reactors. Generally, however, the content of the report focuses on power uprates of the stretch and extended type. The International Atomic Energy Agency (IAEA) is developing a technical guideline on power uprates and side effects of power uprates in nuclear power plants.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3808-3815
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• 2021

In this paper, the EPICS2017 photoatomic database was used to evaluate the photon mass attenuation coefficients and buildup factors of soils collected at different depths in the Philippine islands. The extraction and interpolation of the library was accomplished at the recommended linear-linear scales to obtain the incoherent and total cross section and mass attenuation coefficient. The buildup factors were evaluated using the G-P fitting method in ANSI/ANS-6.4.3. An agreement was achieved between XCOM, MCNP5, and EPICS2017 for the calculated mass attenuation coefficient values. The buildup factors were reported at several penetration depths within the standard energy grid. The highest values of both buildup factor classifications were found in the energy range between 100 and 400 keV where incoherent scattering interaction probabilities are predominant, and least at the region of predominant photoionization events. The buildup factors were examined as a function of different soil silica contents. The soil samples with larger silica concentrations were found to have higher buildup factor values and hence lower shielding characteristics, while conversely, those with the least silica contents have increased shielding characteristics brought by the increased proportions of the abundant heavier oxides.

• 한국콘텐츠학회논문지
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• 제10권7호
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• pp.305-316
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• 2010

기술과학의 발달로 의료분야를 비롯한 이 공학 및 원자력분야에서 방사선학의 중요성은 매우 크다. 과거 특정 분야의 연구만을 하던 과학자들이 현재의 과학기술 환경에서 새로운 분야를 개척하기 위해서는 학문의 융합이 필수적이며, 현재 방사선학과는 여러 학문의 융합으로 주목을 받고 있다. 따라서 본 논문에서는 외국의 환경에 맞게 설계된 선진국의 방사선학과 대학원 및 연구 시스템을 조사 분석하여 국내 방사선학과 대학원 운영 현황과 미래의 학문적 발전을 위한 제안을 하고자 한다. 선진국에서는 학부 및 석사학위 과정 설치 대학의 프로그램 패턴에서는 임상전문가양성 프로그램(초음파 전문가, 방사선 치료 전문가, 핵의학 전문가)을 운영하고 있으며, 학부, 석사 및 박사과정이 설치된 대학의 프로그램 패턴에서는 과학자양성 프로그램(핵의과학자, 방사선공학자, 의학물리학자)을 운영하고 있다. 이를 바탕으로 국내 환경에 맞게 대학원을 수정 및 발전시킨다면 방사선학과는 세계에서도 선도적인 역할을 하는 중요한 학문의 한 분야로 성장할 것으로 사료된다.

• 대한기계학회논문집A
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• 제20권11호
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• pp.3516-3524
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• 1996

Service conditions for structures at elevated temperatures in nuclear power plant involve transient thermal and mechanical load levels that are severe enough to caeuse inelastic deformations due to creep and plasticity. Therefore, a systematic mehtod of inelastic analysis is needed for the design of structural components in nuclear poser plants subjected to such loading conditions. In the present investigation, the Chabodhe model, one of the unified viscoplastic constitutive equations, was selected for systematic inelastic analysis. The material response was integrated based on GMR ( generallized mid-point rule) time integral scheme and provided to ABAQUS as a material subroutine, UMAT program. By comparing results obtaned from uniaxial analysis using the developed UMAT program with those from Runge-Kutta solutions and experimentaiton, the validity of the adopted Chaboche model and the numerical stability and accuracy of the developed UMAT program were verified. In addition, the developed material subroutine was applied for uniaxial creep and tension analyses for the plate with a hole in the center. The application further demonstrates usefulness of the developed program.

• Journal of Nutrition and Health
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• 제43권3호
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• pp.246-259
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• 2010

The incidence of chronic disease is continuously increasing in Korea. Especially, office workers have higher risk of chronic disease because of their dietary habit and lifestyle. The study aimed to investigate the effect of tailored nutrition counseling on improving chronic disease risk factors. Ninety-nine male workers (age $46.9{\pm}7.0$ yrs) volunteered for 12 weeks of nutrition program containing dietary intake and physical activity adjustment. Five individualized programs were performed with the main theme of weight loss (WL, n = 16), blood pressure lowering (BL, n = 34), normalizing blood glucose (GL, n = 21), lipid lowering (LL, n = 13) and reducing MS risk factors (ML, n = 15). Anthropometric data, blood-pressure, self-reported questionnaire, blood profiles were measured before and after 12weeks of nutrition education. The education program included 5 times of 1：1 interview. Compared to 0 week, anthropometric data (weight, BMI, fat, visceral fat, waist, SBP, DBP) were significantly decreased after 12 weeks (p < 0.001). Fasting blood glucose and total cholesterol were decreased (p < 0.05). The primary outcomes with individually tailored programs showed to be more effective than one general nutrition program.

• Corrosion Science and Technology
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• 제19권3호
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• pp.131-137
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• 2020

A number of piping components in the secondary system of nuclear power plants (NPPs) are exposed to aging mechanisms, such as flow-accelerated corrosion (FAC), cavitation, flashing, solid particle erosion, and liquid droplet impingement erosion. Those mechanisms may lead to thinning, leaking, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 in the USA in 1986 and Mihama unit 3 in Japan in 1994, pipe wall thinning management has emerged as one of the most important issues in the nuclear industry. To manage pipe wall thinning, a foreign program has been utilized for NPPs in Korea since 1996. As our experience and knowledge of pipe wall thinning management have accumulated, our program needs to reflect our experience, requests from users, and the result of recent experiments using Flow Accelerated Corrosion Testing System (FACTS). FACTS is the empirical experimental facility developed by Korea Atomic Energy Research Institute (KAERI) for tests. Accordingly, KEPCO-E&C developed a 3D-based pipe wall thinning management program called ToSPACE in 2016. This paper describes a comparison between the FAC analysis results using ToSPACE and the experimental results using FACTS to verify their applicability to pipe wall thinning management in NPPs.