• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.335-343
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• 2005

The Methodology of burnup calculation with EPMA test set up in this study. The spent fuel from PWR nuclear power plant was used as specimen. This $UO_2$ fuel with $3.2\%$ of enrichment had been irradiated up to 35,000 MWd/MTU(reference data). The burnup is very important factor for nuclear fuel to estimate all fuel behaviors in reactor. To measure amounts of fission products and actinides for the burnup calcualation, chemical analysis (destructive method) has been used but it mattes long experimental time and second radio-wastes. In this study, EPMA test was available to measure amount of fission products. Neodymium is able to be detected and quantified. It can be compared with the results from chemical analysis and ORIGEN-2 code calculation. Concentration of Nd from EPMA test showed good agreement with result of ORIGEN-2 code in the same burnup.

• Applied Microscopy
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• v.35 no.3
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• pp.113-119
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• 2005

The Methodology of burnup calculation with EPMA test set up in this study. The spent fuel from PWR nuclear power plant was used as specimen. This $UO_2$ fuel with 3.2% of enrichment had been irradiated up to 35,000 MWd/MTU. The burnup is very important factor for nuclear fuel to estimate all fuel behaviors in reactor. To measure amounts of fission products and actinides for the burnup calcualation, destructive method analysis has been used but it makes long experimental time and second radio-wastes. In this study, EPMA test was available to measure amount of fission products. Neodymium is able to be detected and quantified. It can be compared with the results from chemical analysis and ORIGEN-2 code calculation. Concentration of Nd from EPMA test showed good agreement with result of ORIGEN-2 code in the same burnup.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.251-253
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• 2015

선박에 의한 위험물 운송의 증가로 제정된 IMDG Code를 제정하고, 선원들은 그 규정에 따라 업무를 수행하고 있으며 몇 차례 개정이 되면서 위험물 안전운송 전문교육을 의무화하고 있다. 하지만 해마다 위험물에 의한 선박화재 및 폭발사고는 계속 일어나고 있으며, 이것은 위험물에 대한 기본 정보와 규정만 있으나 위험화물에 대한 자체 반응경로나 왜 규정대로 해야 하는지에 대한 정보가 선원들에게는 부족하다는 것을 알 수 있었다. 그리하여 최근에 발생한 선박화재 및 폭발사고 사례를 조사해보고, 적재된 화학물질 에 대한 기본정보를 분석하고 화재가 일어날 수 있는 가능성에 대해 화학적으로 접근 해석해 보았다. 화재의 원인은 다양하지만 기상 실험을 할 수 없는 어려움이 있어, 적재된 위험물의 정보와 대표적인 반응을 알아보고 화재원인을 가정해 보았다. 선원들은 IMDG Code에 대한 규정 이외에도 이러한 기본정보와 반응경로에 이해를 한다면 위험화물의 운송에 있어 위험한 환경요소를 제거할 수 있어 화재 및 폭발사고를 예방 할 수 있다.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.1-9
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• 2016

Local wall thinning elbow due to the water flow is one of the main degradation phenomenon in carbon steel pipe of plant system. The API579 code of FFS (fitness for service) used in the chemical plant gives a guideline to protect local wall thin problem in a straight pipe, but it does not include an elbow. In this study, the locally wall thinned elbow, which is considered an extrados or intrados wall thinned elbow, was carried out considering in-plane or out-plane bending using FEM (finite element method) analysis, and some of results were also compared with the experimental data. The results could give the structure integrity assessment to protect the local wall thinned elbow.

• Nuclear Engineering and Technology
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• v.24 no.1
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• pp.52-62
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• 1992

Radioactive nuclides deposited on out-of-core surface after the radiation in the core by the transport of corrosion products (CRUD) through the primary coolant system in PWR which is the major plant type in Korea, are leading sources of radiation exposure to plant maintenance personnel. Thus, the optimal chemistry operation method is required for the reduction of radiation exposure by the corrosion products. This study analysed the actual water chemistry operation data of four operating domestic PWRs. And in order to evaluate the coolant chemistry operation data, a computer code which can calculate the activity buildup in the various chemistry conditions of PWR coolant was employed. Through the analysis of comparison between the activity buildup of actual water chemistry operation mode and that of assumed Elevated Li operation mode calculated by the computer code, it was found that the out-of core radioactivity can be reduced by diminishing the deposition of corrosion products on the core in case that the Elevated Li operation mode is applied to the coolant chemistry operation of PWR. And the higher coolant pH operation was shown to have the advantage of the reduction of out-of-core activity buildup if the integrity of system structural materials and fuel cladding is guaranteed.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.258-264
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• 2010

Most of fluid systems, such as P&ID in ships, power plants, and chemical plants, consist of various components. The components such as bends, tees, sudden-expansions, sudden-contractions, and orifices contribute to overall pressure loss of the system. The local pressure losses across such components are determined using a pressure loss coefficient, k-factor, in lumped parameter models. In many engineering problems Idelchik's k-factor models have been used to estimate them. The present work compares the k-factor based on CFD calculation against Idelchik's model in order to confirm whether a commercial CFD package can be used for pressure loss coefficient estimation of complex geometries. The results show that RSM is the best appropriate for evaluating pressure loss coefficient. Commercial CFD package can be used as a tool evaluating k-factor even though the accuracy is influenced by a turbulence model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.105-109
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• 2007

Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were used to rocket nozzle flow, those were coupled with the methods of computational fluid dynamics code. For a design of high temperature rocket nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be an efficient design tool for predicting maximum thermodynamic performance of the nozzle. In this study, shifting-equilibrium flow analysis was carried out for the 30 $ton_f$-class KARl liquid rocket engine nozzle together with frozen flow. The performance evaluation based on the 30 $ton_f$-class KARl LRE nozzle flow analyses will provide an understanding of the thermochemical process in the nozzle and performances of nozzle.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.85-96
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• 2003

For a design of rocket engine nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be used as an efficient design tool for predicting maximum thermodynamic performance of the nozzle. 10 this study, a chemical equilibrium flow analysis code was developed for the design of hydrocarbon fueled rocket engines. 10 oder to understand the thermochemical characteristics occurring in a nozzle through the expansion process, such as recombination of chemical components and the accompanying energy recovery, chemical equilibrium flow analysis was carried out for the KSR-III rocket engine nozzles together with frozen flow and non-equilibrium flow analyses. The performance evaluation based on the present KSR-III nozzle flow analyses has provided an understanding of the thermochemical process in the nozzle and additionally, it has confirmed that the newly designed nozzle shape modified to have a reduced exit area ratio is an adequate design for obtaining an increased ground thrust.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.11a
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• pp.50-55
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• 1995

향상되어진 93-PCGC-2는 기존의 PCGC-2와 같이 미분탄 연소를 포함하는 다양한 반응성흐름과 비반응성 흐름을 설명하기 위해 2차원 정상상태 모델로 제시되어 졌다. 93-PCGC-2는 실린더형의 축 대칭계에 응용되어질 수 있고, 난류(Turbulence)는 유체역학식과 연소기구 양쪽을 위해 고려되어졌으며, 불연속 세로좌표 방법(Discrete Ordinates Method)을 이용하여 기체, 벽 및 입자들로부터의 복사열(Radiation)을 모사하였다. 입자상은 입자 무리들의 평균 경로들을 따라 해석하는 Lagrangian계의 해석법으로 모델화되어졌다. 석탄의 팽윤(Swelling)과 촤의 반응성에 관한 부모델과 더불어 새롭게 일반화된 석탄 탈휘발화 부모델 (FG-DVC)도 첨가되어졌다. 비균일 반응기구는 확산과 화학반응 둘 모두를 고려하였다. 주요 기상반응은 국부 순간 평형을 가정하여 모델화하였다. 그래서 반응속도는 혼합의 난류속도에 의해 제한되어진다. Thermal NOx과 Fuel NOx의 유한속도 화학론(Finite Rate Chemstry)에 대한 부모델은 화학반응속도론와 난류성의 통계치를 통합하여 만들어져 있다. 기상은 반복적인 line-by-line기교에 의해 풀려지는 elliptic partial differential equation으로 묘사되어진다. 수치적인 안정을 고려하기 위해 under-relaxation이 이용되어졌다. 이렇게 코드화된 93-PCGC-2는 연소를 위해 모사되어졌다. 또한 더 나아가 이 수치모델의 활용범위는 미분탄의 가스화에도 활용되어질 것으로 기대되어진다.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.6
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• pp.48-55
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• 2008

We have simulated the performance of a simple engine model with a gas turbine engine simulation program based on CFD. 2-dimensional Navier-Stokes code for the viscous flow was applied to simulate a compressor and a turbine, and the chemical equilibrium code with the lumped method was applied to simulate the combustor. Unsteady-flow phenomenon between rotor and stator of the compressor and the turbine was analyzed by steady mixing-plane method. In this way, the influence of the turbine blade pitch on the engine was investigated. It was shown that the compressor is operated at more higher pressure conditions as narrower the pitch distance of the turbine.