• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.512-515
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• 2000

A parallel reactor system which is consisted of two trickle bed reactors (TBR) was developed for the biodegradation of trichloroethylene (TCE) in waste gas stream. The reactor were packed with porous ceramic materials and Burkholderia cepacia G4 was inoculated to form biofilms. Each reactor was operated alternatively in TCE degradation or reactivation mode, and the effect of switching time on TBR performance was investigated. The MO (monooxygenase) activity during the TCE transformation decreased below 10 % within 24 hr, but could be recovered to the initial high level within 10 hr after supplying the reactivation medium supplemented with phenol as a carbon source. This shows that the parallel TBR system has a great potential for the long-term stable treatment of TCE.

• Nuclear Engineering and Technology
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• 제44권5호
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• pp.501-506
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• 2012

Many innovative design features are employed in the reactor vessel internals of SMART, a small integral-type pressurized water reactor, one of which is the flow skirt, which uniformly distributes flow and horizontally restrains the lower part of the core support barrel. This new design requires a comprehensive investigation of vibration characteristics. Therefore, in this study, modal characteristics of flow skirts are investigated with finite element analysis. Specifically, we investigate how the presence of holes, the presence of three rings attached to the flow skirt, and the thickness of the lowest shell effect vibration characteristics. In addition, the fluid effect is addressed, since the flow skirt is submerged in the fluid.

• 대한기계학회논문집A
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• 제36권10호
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• pp.1283-1288
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• 2012

수소를 대량으로 생산하기 위한 원자력수소생산시스템에서 공정열교환기는 초고온가스로로부터 생성된 초고온 열을 화학반응공정으로 전달하는 핵심기기이다. 한국원자력연구원에 구축되어 있는 소형 가스루프에서 $Hastelloy^{(R)}$-X 로 제작된 중형 공정열교환기 시제품에 대한 성능시험이 계획되어 있다. 본 연구에서는 중형 공정열교환기의 고온구조건전성을 파악하기 위한 선행 연구로서 소형가스루프 시험조건하에서 중형 공정열교환기 시제품의 고온구조해석을 이전 연구에서 확립된 경계조건을 적용하여 수행하였다. 해석결과는 소형가스루프에서의 중형 공정열교환기 시제품에 대한 성능시험 결과와 비교할 예정이다.

• 대한기계학회논문집B
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• 제34권5호
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• pp.553-561
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• 2010

한국원자력연구원에서는 초고온가스로를 모사할 수 있는 중형 헬륨 회로를 건설 중에 있다. 이 실험헬륨 회로에서 두 개의 전기 가열기가 헬륨 유체를 1 ~ 9 MPa 의 압력 하에서 $950^{\circ}C$ 까지 가열하게 된다. 이 실험 헬륨 회로의 설계 사양을 최적화하기 위하여, 본 연구에서는 두 개의 가열기 중 하류에 위치한 고온헬륨가열기 안의 복합열전달 현상을 전산유체역학으로 해석하였다. 해석 결과에서 헬륨 가열기 내 최대 온도는 허용 한계를 넘지 않았고, 이로써 선정된 기하구조의 열적 특성은 설계요건을 만족함이 확인되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3353-3358
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• 2007

The present paper is devoted to investigate dynamic effect and steady-state performance of methane autothermal reformer theoretically and numerically. In order to simplify the complicated phenomena in the system, axisymmetric heterogeneous reactor model is developed. As autothermal reaction takes places on catalyst surface between bulk gas and catalyst, volume averaging method is incorporated using porous medium approach. To understand the start-up process which occurs in the reactor is highly important. Therefore, in this paper we get various goverining equations to find out transient and steady solutions and time scale for start-up introducing dimensionless variables. Start-up is a significant issue in reforming reaction for automobile system and fueling of SOFC-based auxiliary power units. This paper deals with characteristics of heat and mass transfer and predicted light-off time in the reformer as oxygen to carbon ratio ($O_2$/C) and amount of feeding gas.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.227-234
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• 2004

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion(CLC) may yield great advantages of savings of energy to $CO_2$ separation and suppressing the effect on environment. In chemical-looping combustor, fuel is oxidized by metal oxide medium (oxygen carrier particle) in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. The purpose of this study is to demonstrate inherent $CO_2$ separation and no NOx emission and to confirm high $CO_2$ selectivity, no side reaction (i.e., carbon deposition, hydrogen generation) by continuous reduction and oxidation experiment in a 50kWtb chemical-looping combustor. NiO/bentonite particle was used as a bed material and $CH_4$ and air were used as reacting gases for reduction and oxidation respectively.

• 시스템엔지니어링학술지
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• 제10권1호
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• pp.33-41
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• 2014

New design concept of Reactor Coolant System (RCS) including a reactor assembly for the SMR is introduced in this work. An exploration of new type of reactor that is advanced from proposed SMRs is performed by using systems engineering approach. In this point of view project structured on three main phases; needs analysis (NA), concept exploration (CE), and concept definition (CD). Main objectives as an output of the CE stage are a small size, low cost, shortening the schedule, and enhancing safety. The SMRs usually have a small size requirement. In order to meet the size requirement and to achieve a productivity, in other words, easiness to manufacture, this paper suggests an integrated PWR design concept through researching predecessors. Although the integrated PWR concept provides many advantages, it has disadvantages that composite of maintenance and a low availability problem. Therefore, this paper comes up with a run-to-fail design concept based on modular design to address the maintenance problem and to maximize the availability of SMRs as well as to be compatible with the overall-SMRs including Barge Mounted(BM)type.

• 에너지공학
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• 제6권1호
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• pp.87-95
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• 1997

금속염화물과 암모니아간의 가역반응을 이용한 화학열펌프는 비프레온계 냉동 냉장시스템으로서 환경규약의 제한이 없고 가스, 전기 및 산업폐열 등 다양한 구동열원을 사용할수 있으며 축열에 의한 에너지 저장이나 산업공정에서의 대용량 에너지관리 시스템 등 응용분야가 다양한 장점을 갖고 있다. 통상 소규모의 실험실 장치에서 파일롯트 플랜트(pilot plant)로 전환하는 과정에서 시스템의 성능에 대한 해석이 필요하며 화학반응기의 거동에 대한 컴퓨터 모사도 필수적이다. 따라서 본 연구에서는 작동조건에 따라 화학식 냉동기 성능계수가 어떻게 변하는지를 예측하였고 반응기 모델링에 의한 동적모사를 수행하여 반응기의 온도거동, 작동조건에 따른 전화율 변화, 반응혼합물의 제조변수가 냉동기 성능에 미치는 영향 등을 고찰하였다.

• 생명과학회지
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• 제14권1호
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• pp.167-173
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• 2004

Lactobacillus brevis BH-21의 균체를 고정화하여 column형 reactor를 이용하여 $\gamma$-aminobutyric acid의 연속적 생산을 검토하였다. Lactobacillus brevis BH-21에 의한 $\gamma$-aminobutyric acid 생산조건은 고정화 담체로는 3.0% sodium alginate가 좋았고 직경 2.2 mm의 bead를 사용하여 기질의 주입속도는 10 mL/h이 최적 조건이었다. Lactobacillus brevis BH-21의 고정화 균체와 유리 균체를 사용하여 $\gamma$-aminobutyric acid의 생산을 최적 조건하에서 1, 2, 3, 및 4차 발효 동안 48시간마다 신선한 기질을 주입하면서 비교ㆍ조사한 결과 고정화 균체를 사용 시에 생산량이 더 많았다. Column형 reactor에 의한 연속 발효 시 발효 25일까지 생산이 우수하였고 발효 30일까지는 $\gamma$-aminobutyric acid를 생산할 수 있었다.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.732-740
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• 2021

Scattering resonance of medium mass nuclides leads complex spectrum in the fast reactor, which requires thousands of energy groups in the spectrum calculation. When the broad-group cross sections are collapsed, reaction rate cannot be completely conserved. To eliminate the error from energy collapsing, the Super-homogenization method in energy collapsing (ESPH) was employed in the fast reactor code SARAX. An ESPH factor was derived based on the ESPH-corrected SN transport equation. By applying the factor in problems with reflective boundary condition, both the effective multiplication factor and reaction rate were conserved. The fixed-source iteration was used to ensure the stability of ESPH iteration. However, in the energy collapsing process of SARAX, the vacuum boundary condition was adopted, which was necessary for fast reactors with strong heterogeneity. To further reduce the error caused by leakage, an additional conservation factor was proposed to correct the neutron current in energy collapsing. To evaluate the performance of ESPH with conservation factor, numerical benchmarks of fast reactors were calculated. The results of broad-group calculation agreed well with the direct full-core Monte-Carlo calculation, including the effective multiplication factor, radial power distribution, total control rod worth and sodium void worth.