• 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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• 제29권4호
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• pp.348-359
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• 1997

This paper reviews cooling aspects of the diverter system in Tokamak fusion devices with primary emphasis on the critical heat flux (CHF) issues for oater-cooled designs. General characteristics of four (4) coolant options for diverter cooling gases, oater, liquid metal, and organic liquid - are discussed first, focusing on the comparison of advantages and disadvantages of those options. Then results of recent studies on the high-heat-flux CHF of water at subcooled high-velocity conditions are reviewed to provide a general idea on the feasibility of the water-cooled diverter concept for future Tokamak fusion reactors. Water is assessed to be the most viable and practical coolant option for diverters of future experimental Tokamaks.

• Nuclear Engineering and Technology
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• 제38권6호
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• pp.561-574
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• 2006

This study presents the results of an economic analysis for a comparison of the single layer and double layer alternatives with respect to a HLW-repository. According to a cost analysis undertaken in the Korean case, the single layer option was the most economical alternative. The disposal unit cost was estimated to be 222 EUR/kgU. In order to estimate such a disposal cost, an estimation process was sought after the cost objects, cost drivers and economic indicators were taken into consideration. The disposal cost of spent fuel differs greatly from general product costs in the cost structure. Product costs consist of direct material costs and direct labor and manufacturing overhead costs, whereas the disposal cost is comprised of construction costs, operating costs and closure costs. In addition, the closure cost is required after a certain period of time elapses following the building of a repository.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.58-63
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• 1996

This paper is devoted to evaluating the accuracy of general 2D geometric transport code, HELIOS, and determining the order of merit in modeling for some important HELIOS input parameters. Benchmark test for 12 critical lattices show that HELIOS predicts criticality accurately within experimental uncertainties, showing only 250 pcm overestimation with a standard deviation of 450 pcm. The sensitivity test suggest that current coupling order, neutron group library, geometrical modeling, and resonance options must be considered carefully to obtain accurate results. Especially, current coupling order and sub-rings in fuel regions turn out to be most critical in HELIOS modeling. For MOX loaded cores, it is additionally necessary to pay attention to the resonance option and the validity of small group neutron library.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2295-2303
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• 2021

To investigate wall-thinning impact on axial load resistance of Zircaloy-4 cladding rods after a LOCA transient, axial tensile samples have been machined on as-received tubes with reduced thicknesses between 370 and 580 ㎛. After high temperature oxidation under steam at 1200 ℃ with measured ECR ranging from 10 to 18% and water quenching, machined samples were axially loaded until fracture. These tests were modeled using a fracture mechanics approach developed in a previous study. Fracture stresses are rather well predicted. However, the slightly lower fracture stress observed for wall-thinned samples is not anticipated by this modeling approach. The results from this study confirm that characterizing the axial load resistance using semi-integral tests including the creep and burst phases was the best option to obtain accurate axial strengths describing accurately the influence of wall-thinning at burst region.

• Journal of Radiation Protection and Research
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• 제18권1호
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• pp.71-82
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• 1993

원자력 발전소 작업과의 피폭량은 발전소의 안전 운영에 관한 척도일 뿐 아니라, 일반 대중이 원자력 발전의 안전을 평가하는 기본 요소이다. 또한, 최근 ICRP 60에 의한 개인 피폭선량 한도의 하향조정 권고는 지속적인 피폭저감에의 노력을 요구하고 있다. 본 논문에서는 작업자의 피폭저감에 관한 대안선정시 사용할 수 있는 최적화 기법을 제시하고 실제로 원전 운영자예 의해 제안된 대안들을 검토하는데 이 기법을 적용하여 보았다. 분석과정에서 기본분석이외에 가변 경제변수를 고려한 민감도 분석을 통해 계산 결과의 불확실성을 보완하였다. 분석결과를 살펴보면, 먼저 비용-이득 분석에서는 '증기 발생기 Nozzle Dam 및 Torquing Machine'이 총 이득면에서 가장 우수한 것으로 평가되었고, 다속성 효용 분석의 경우 'Co-No Seal 조임장치'가 가장 높은 효용을 가진 것으로 나타나 약간의 차이를 보이고 있다. 따라서, 최적화 기법의 적용시에는 두 가지이상의 정량적 기법을 보완적으로 사용하고, 정성적 인자도 충분히 고려하는 것이 필요하다.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.73-87
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• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• Nuclear Engineering and Technology
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• 제42권3호
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• pp.249-258
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• 2010

Recently, many utilities have considered interim dry storage of spent nuclear fuel as an option for increasing spent fuel storage capacity. Foreign nuclear regulatory committees have provided some regulatory and licensing requirements for relatively low- and medium-burned spent fuel with respect to the prevention of spent fuel degradation during transportation and interim dry storage. In the present study, the effect of cladding creep and hydride distribution on spent fuel degradation is reviewed and performance tests with high-burned Zircaloy-4 and advanced Zr alloy spent fuel are proposed to investigate the effect of burnup and cladding materials on the current regulatory and licensing requirements. Creep tests were also performed to investigate the effect of temperature and tensile hoop stress on hydride reorientation and subsequently to examine the temperature and stress limits against cladding material failure. It is found that the spent fuel failure is mainly caused by cladding creep rupture combined with mechanical strength degradation and hydride reorientation. Hydride reorientation from the circumferential to radial direction may reduce the critical stress intensity that accelerates radial crack propagation. The results of cladding creep tests at $400^{\circ}C$ and 130MPa hoop stress performed in this study indicate that hydride reorientation may occur between 2.6% to 7.0% strain in tube diameter with a hydrogen content range of 40-120ppm. Therefore, it is concluded that hydride re-orientation behaviour is strongly correlated with the cladding creep-induced strain, which varies as functions of temperature and stress acting on the cladding.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.148-164
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• 2017

The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.37-44
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• 2007

For the past few years, the concern for clean energy has been greatly increased. Ocean Thermal Energy Conversion(OTEC) power plants are studied as a viable option for the supply of clean energy. In this paper, the thermodynamic performance of OTEC cycle was examined. Computer simulation programs were developed under the same condition and various working fluids for closed Rankine cycle, regeneration cycle, Kalina cycle, open cycle and hybrid cycle. The results show that the regeneration cycle using R125 showed a 0.17 to 1.56% increase in energy efficiency, and simple Rankine cycle can generate electricity when the difference in warm and cold sea water inlet temperatures are greater than $15^{\circ}C$. Also, the cycle efficiency of OTEC power plant using the condenser effluent from nuclear power plant instead of the surface water increased about 2%.