3-Dimensional Analysis of the Steam-Hydrogen Behavior from a Small Break Loss of Coolant Accident in the APR1400 Containment

Kim Jongtae,Hong Seong-Wan,Kim Sang-Baik,Kim Hee-Dong,Lee Unjang,Royl P.,Travis J. R. Korean Nuclear Society 2004 Nuclear Engineering and Technology Vol.36 No.1

In order to analyze the hydrogen distribution during a severe accident in the APR1400 containment, GASFLOW II was used. For the APR1400 NPP, a hydrogen mitigation system is considered from the design stage, but a fully time-dependent, three-dimensional analysis has not been performed yet. In this study GASFLOW code II is used for the three-dimensional analysis. The first step to analysis involving hydrogen behavior in a full containment with the GASLOW code is to generate a realistic geometry model, which includes nodalization and modeling of the internal structures such as walls, ceilings and equipment. Geometry modeling of the APR1400 is conducted using GUI program by overlapping the containment cut drawings in a graphical file format on the mesh view. The total number of mesh cells generated is 49,476. And the calculated free volume of the APR1400 containment by GASFLOW is almost the same as the value from the GOTHIC modeling. A hypothetical SB-LOCA scenario beyond design base accident was selected to analyze the hydrogen behavior with the hydrogen mitigation system. The source of hydrogen and steam for the GASFLOW II analysis is obtained from a MAAP calculation. Combustion pressure and temperature load possibilities within the compartments used in the GOTHIC analysis are studied based on the Sigma-Lambda criteria. Finally the effectiveness of HMS installed in the APR1400 containment is evaluated from the point of severe accident management

원자로 노심 용융물의 고압분출 및 비산 현상에 대한 수치해석적 연구

김종태(Jongtae Kim),김상백(Sang-Baik Kim),김희동(Hee-Dong Kim),정재식(Jae-Sik Jeong) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.11

During a hypothetical high-pressure accident in a nuclear power plant (NPP), molten corium can be ejected through a breach of a reactor pressure vessel (RPV) and dispersed by a following jet of a high-pressure steam in the RPV The dispersed corium is fragmented into smaller droplets in a reactor cavity of the NPP by the steam jet and released into other compartments of the NPP by a overpressure in the cavity. The fragments of the corium transfer thermal energy to the ambient air in the containment or interact chemically with steam and generate hydrogen which may be burnt in the containment. The thermal loads from the ejected molten corium on the containment which is called direct containment heating (DCH) can threaten the integrity of the containment. DCH in a NPP containment is related to many physical phenomena such as multi-phase hydrodynamics, thermodynamics and chemical process. In the evaluation of the DCH load, the melt dispersion rates depending on the RPV pressure are the most important parameter. Mostly, DCH was evaluated by using lumped-analysis codes with some correlations obtained from experiments for the dispersion rates. In this study, MC3D code was used 10 evaluate the dispersion rates in the APR1400 NPP during the high-pressure accidents, MC3D is a two-phase analysis code based on Eulerian four-fields for melt jet, melt droplets, gas and water. The dispersion rates of the corium melt depending on the RPV pressure were obtained from the MC3D analyses and the values specific to the APR1400 cavity geometry were compared to a currently available correlation.

Antisteatotic Efficacy and Safety of the Liver X Receptor Alpha Inhibitor, Dithiolethione in Patients with Nonalcoholic Fatty Liver Disease

Won Kim,June Sung Lee,Chun Kyon Lee,Jong Eun Yeon,Mee Soo Chang,Jung Ho Kim,Hyeonjin Kim,Jongtae Lee,Joo-Youn Cho,Byeong Kwan Kim,Yoon Jun Kim 한국간담췌외과학회 2014 한국간담췌외과학회 학술대회지 Vol.2014 No.4

APR1400의 급수완전상실사고 시 격납건물 내에서 수소와 수증기의 3차원 거동에 대한 수치해석

김종태(Jongtae Kim),홍성완(Seong-Wan Hong),김상백(Sang-Baik Kim),김희동(Hee-Dong Kim) 한국전산유체공학회 2005 한국전산유체공학회지 Vol.10 No.3

During a hypothetical severe accident in a nuclear power plant (NPP), hydrogen is generated by the active reaction of fuel-cladding and steam in the reactor pressure vessel and released with steam into the containment. In order to mitigate hydrogen hazards possibly occurred in the NPP containment, hydrogen mitigation system (HMS) is usually adopted. The design of the next generation NPP (APR1400) designed in Korea specifies 26 passive autocatalytic recombiners and 10 igniters installed in the containment for the hydrogen mitigation. In this study, the analysis of the hydrogen and steam behavior during a total loss of feed water (TLOFW) accident in the APR1400 containment has been conducted by using the CFD code GASFLOW. During the accident, a huge amount of hot water, steam, and hydrogen is released in the in-containment refueling water storage tank (IRWST). The current design of the APR1400 includes flap-type dampers at the IRWST vents which are operated depending on the pressure difference between inside and outside of the IRWST. It was found that the flaps strongly affects the flow structure of the steam and hydrogen in the containment. The possibilities of a flame acceleration and transition from deflagration to detonation (DDT) were evaluated by using Sigma-Lambda criteria. Numerical results indicate the DDT possibility could be heavily reduced in the IRWST compartment when the flaps are installed.

한국 발전주의의 담론 구조

김종태(Kim Jongtae) 비판사회학회 2014 경제와 사회 Vol.- No.103

이 논문은 ‘근대화’, ‘세계화’, ‘선진화’ 등 시대 별로 제시된 대표적인 발전주의적 구호를 둘러싼 담론에 대한 분석을 통해 발전주의의 담론 구조를 밝히고자 한다. 박정희, 김영삼, 이명박 대통령의 연설문을 분석 자료로 삼았다. 연구결과, 한국의 지배적 발전주의 담론은 ‘목표 설정’, ‘문제 제기’, ‘위기 조성’, ‘저력 상기’, ‘전략’ 등 다섯 개의 주요 요소로 구성되어 있는 것으로 나타났다. 목표는 모든 시기에 ‘선진국’이 궁극적으로 추구되었지만, 박정희 집권 초기에는 ‘후진국 탈피’가 더 시급하게 여겨지는 경향이 강했다. 발전주의는 ‘저발전’ 상태를 ‘문제화’하는데, 대체로 박정희 집권 초기 ‘후진국’의 상태를, 이후에는 ‘선진국 문턱’의 상태를 문제화했다. 이와 함께 발전주의는 치열한 국제경쟁속에서 한국은 선진국 진입과 탈락의 갈림길에서 쫓기는 위치에 있다는 인식을 통해 위기의식을 조성했다. 위 담론 요소들이 목표 달성의 막중함과 관계가 있다면, 민족적, 국가적 ‘저력의 상기’는 그 가능성을 강조한다. 발전주의는 근대화, 세계화, 선진화 등 시대별 상황을 반영한 전략적 하위 담론을 통해 구체적인 국가 변화의 방향을 설정해왔다. 이 연구는 발전주의가 한국 사회의 물질적 향상에 기여했지만 동시에 한국인의 삶을 매우 피로하게 해온 요인임을 지목하고, 발전주의와 선진국 개념에 대한 재성찰을 요구한다. This paper examines the structure of developmentalism in Korea through the analysis of historically representative developmental discourses: ‘geundaehwa’ (modernization), ‘segyehwa’(globalization), and ‘seonjinhwa’(becoming advanced). It analyzes the presidential addresses of Park Chung-Hee, Kim Young-Sam, and Lee Myung-Bak. The analysis shows that developmentalism in Korea mainly consists of five elements: ‘goal setting,’ ‘problematization,’ ‘crisis construction,’ ‘reminding of national potential,’ and ‘strategies.’ As for the goal setting, it has pursued ‘seonjinguk’ all through the periods, while there was a tendency to focus on ‘escaping from hujinguk(underdeveloped country)’ in the early Park era. As developmentalism problematizes ‘underdevelopment,’ its Korean version has problematized the status of hujinguk in the early Park era, and the status of ‘seonjinguk munteok’ (on the threshold of seonjinguk) afterwards. Korean developmentalism also raises the consciousness of crisis by promoting a perception that Korea is on a forked road either entering into or dropping out of seonjinguk. While those elements are relevant to the significance of achieving the goal, the reminding of national potential is to emphasize its prospect. Developmentalism has directed national transformation through the strategic sub-discourses of geundaehwa, segyehwa, and seonjinhwa, reflecting different historical circumstances. This paper argues that developmentalism is a main discursive factor for Koreans’ tiredness despite its contribution to Korea’s material improvement, and raises a need to reconsider developmentalism and the concept of seonjinguk.

원자력발전소 격실에서의 수소화염 가속에 대한 수치해석 연구

김종태(Jongtae Kim),김상백(Sang-Baik Kim),김후중(Hoo-Joong Kim) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11

hydrogen safety is one of impotant issues for future public usage of hydrogen. When hydrogen is released in a compartment, the occurance of detonation must be prohibited. In order to evaluate the possibility of DDT in the compartment with the hydrogen release, sigma-lambda criteria which were developed from experimental data are commonly used. But they give a little conservative results because they do not consider the detailed geometrical effect of the compartment. This is the main reason of the need to mechanistic combustion model for evaluation of hydrogen flame propagation and acceleration. In this study, sigma-lambda criteria and combustion model were systematically applied to evaluate a possibility of DDT in a IRWST compartment of APR1400 nuclear power plant during a hypothetical accident. A combustion model in an open source CFD code OpenFOAM has been applied to analyses of hydrogen flame propagation. The model was validated by evaluating the flame acceleration tests conducted in FLAME facility. And it was applied to evaluate the characteristics of a hydrogen flame propagation in the IRWST compartment of APR1400.

비압축성 열유동 해석을 위한 비엇갈림 격자법에 대한 연구

김종태(Jongtae Kim),김상백(Sang-Baik Kim),김희동(Hee-Dong Kim) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.9

The non-staggered(colocated) approach for which all the solution variables are located at the centers of control volumes are very popular in finite volume methods. Rhie and Chow’s paper is the first in using non-staggered method for incompressible SIMPLE algorithm. They used pressure weighted interpolation to prevent decoupling of pressure and velocity. During the authers’ recent research it was found that Rhie-Chow’s interpolation to define face velocity contaminates velocity fields near walls especially for natural convection problems. The reason to unwanted solution is from overspecified third derivative of pressure in interpolated face velocity. The pressure damping term in face velocity is limited to prevent physically unreasonable solutions. The wall pressure extrapolation which is necessary for cell-centered FVM is another source of numerical diffusion. Some methods are applied in a unstructured FV solver and analyzed in view of numerical accuracy.

APR1400 원자력발전소 격납건물 내에서 급수완전상실사고 발생시 수소와 수증기의 3차원 거동에 관한 연구

김종태(Jongtae Kim),홍성완(Seong-Wan Hong),김상백(Sang-Baik Kim),김희동(Hee-Dong Kim) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.8

밀폐된 격실에서의 수소화염 가속에 대한 수치해석

김종태(Jongtae Kim),김상백(Sang-Baik Kim),김군홍(GunHong Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11

When a hydrogen released and mixed with air in a tightly-closed volume is burnt, its flame can be accelerated in the case of its concentrations higher than 10 vol%. The accelerated flame could become a detonation which is led by a shock wave. It has been shown from the accident of the nuclear power plants at Hukushima how a hydrogen burn in a confined volume such as the reactor building is explosive and devastating. For a confined volume which has a possibility of a hydrogen leakage, it is needed to evaluate the characteristics of the flame propagation and to install a hydrogen control system or to ensure structural strength resisting to pressure load from an explosion. In order to numerically evaluate the possibility of a hydrogen flame acceleration in a confined volume, efforts have been made to implement existing numerical schemes and combustion models. Recently international research projects for hydrogen flame propagation in confined vessels such as ENACEFF and THAI have been conducted the purpose of the projects is to generate experimental data for the validation of numerical codes. In this study, a combustion solver in OpenFOAM is applied to simulation of the hydrogen flame propagations in the ENACEFF and THAI vessels. The numerical results are compared with the experimental data to show the applicability of the CFD code to real containments.

원자력발전소 격실에서의 수소화염 가속에 대한 수치해석 연구

김종태(Jongtae Kim),김상백(Sang-Baik Kim),김후중(Hoo-Joong Kim) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.4

Hydrogen safety is one of important issues for future public usage of hydrogen. When hydrogen is released in a compartment, the occurrence of detonation must be prohibited In order to evaluate the possibility of DDT (Deflagration to Detonation Transition) in the compartment with the hydrogen release, sigma-lambda criteria which were developed from experimental data are commonly used But they give a little conservative results because they do not consider the detailed geometrical effect of the compartment. This is the main reason of the need to mechanistic combustion model for evaluation of hydrogen flame propagation and acceleration. In this study, sigma-lambda criteria and combustion model were systematically applied to evaluate a possibility of DDT in a IRWST compartment of APRI400 nuclear power plant during a hypothetical accident. A combustion model in an open source CFD code Open FOAM has been applied for analyses of hydrogen flame propagation. The model was validated by evaluating the flame acceleration tests conducted in FLAME facility. And it was applied to evaluate the characteristics of a hydrogen flame propagation in the IRWST compartment of APR1400.