• Nuclear Engineering and Technology
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• 제31권3호
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• pp.276-286
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• 1999

A computer code PARS2 is developed for the analysis of PSDRS, which is the safety grade RHRS of HAMMER, and applied to the investigation of the relation between design parameters and performance of PSDRS. The concept of the heat transfer resistance network is applied in assessing the importance of the various heat transfer modes. From the analysis results, the qualitative relations between the PSDRS performance and design parameters are found and guidelines for the PSDRS design procedures are also proposed.

• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.687-694
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• 1999

This study was conducted to develop new drying process for automatic control and marine engi-neering system. Air-water tests were carried out to investigate dryer performance. The dispersed flow in he dryer test apparatuses was also simulated by using a numerical code which solves the Dittus-Boelter equation for continuous liquid phase and the Reynolds equation of droplet motion for continuous liquid phase and the Reynolds equation of droplet motion for dispersed phase to predict droplet removal efficiency. Proper conditions for dehumidification were optimized by response ambient conditions. When the selected indexes were constrained in the range of 85-98% moisture content above $15^{\circ}$ and more than mass flow rates of moist air 750kg/h. The numerical results were compared with the experimental data pertaining to the removal effi-ciency at chamber stage and overall pressure drop along concentric tubes Good agreement was obtained as for the efficiency while relatively poor agreement was obtained for the relative humidity. The results also showed that the efficiency depended strongly on the relative humidity at the inlet condition which indicated the importance of estimating the heat exchanger length. Effects of some design parameters in both removal efficiency and breakthrough onset condition are discussed.

• Journal of Radiation Protection and Research
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• 제43권1호
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• pp.20-28
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• 2018

Background: Heat energy produced in nuclear reactors and nuclear fuel cycle facilities interactions modifies the physical properties of the shielding materials containing water content. Therefore, in the present paper, effect of the heat on shielding effectiveness of the concretes is investigated for gamma and neutron. The mass attenuation coefficients, effective atomic numbers, fast neutron removal cross-section and exposure buildup factors. Materials and Methods: The mass attenuation coefficients, effective atomic numbers, fast neutron removal cross-section and exposure buildup factors of ordinary and heavy concretes were investigated using NIST data of XCOM program and Geometric Progression method. Results and Discussion: The improvement in shielding effectiveness for photon and reduction in fast neutron for ordinary concrete was observed. The change in the neutron shielding effectiveness was insignificant. Conclusion: The present investigation on interaction of gamma and neutron radiation would be very useful for assessment of shielding efficiency of the concrete used in high temperature applications such as reactors.

• 공업화학
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• 제31권5호
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• pp.575-580
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• 2020

본 연구에서는 열 안정성 염 제거장치가 추가된 아민 재생 공정을 모사하고, 폐수 량, 열 안정성 염 제거 량, MDEA(methyl diethanolamine) 손실량을 고려한 최적 운전조건 도출 전략을 제시하였다. 산성 가스를 흡수 및 탈거하는 아민 재생공정에서 열 안정성 염은 공정 장비 및 아민 용액의 흡수 효율을 저해한다. 열 안정성 염 제거 방법 중 하나인 이온교환수지법은 NaOH와 같은 강 염기성 용액을 사용하여 중화반응을 통해 염을 제거시키는 방법이다. 공정 모델링 과정에서 산성 가스의 탈거 과정은 Radfrac 모델을 사용했고, 반응의 평형상수는 Gibbs 자유에너지를 사용하여 계산하였다. 탈거된 아민 용액의 일부는 열 안정성 염 제거 장치로 들어가게 되고, 제거 장치는 중화반응을 이용한 Rstoic 모델을 사용하였다. 실제 운전데이터와 시뮬레이션 결과를 비교하여 검증하였고, 제거 장치로 들어가는 질량 유량을 조절하여 사례연구를 하고 최적 운전 조건을 제시하였다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2002년도 추계 학술발표회 논문집
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• pp.111-116
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• 2002

고온의 소듐을 냉각재로 사용하는 풀형 액체금속로인KALIMER[1]는 기존의 경수로에 비해 고온에서 운전되므로, 잔열제거계통은 공기 자연순환에 의해 격납용기(CV) 외벽을 직접 냉각하는 방식의 PSDRS(Passive Safety-grade Decay Heat Removal System)[1]를 사용하며, 특히 고온의 구조물 표면온도에 의해 대류전열 외에도 복사전열과정이 활발히 일어난다.(중략)

• 동력기계공학회지
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• 제13권6호
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• pp.76-81
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• 2009

Thermal desorption systems are designed to remove organic compounds from solid matrices such as soils, sludges and filter cakes without thermally destroying them. It is a separation technology, not a destruction technology. Since it is a thermal process, there is a common belief that temperature is the only significant parameter to be monitored. While it is true that better removal efficiencies are usually achieved at higher temperatures, other factors must be considered. Since the process is governed by mass transfer, heating time and the amount of mixing are also key parameters in optimizing removal efficiency. Thermal desorption have been successfully used for just about every organic contaminant found to date. It has also been used to remove mercury. In the present study, the numerical simulation has been performed to investigate the characteristics of heat transfer of LTTD(low temperature thermal desorption). The commercial software, AMESIM was applied for analyzing the heat transfer process in the LTTD.

• 한국의류산업학회지
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• 제2권5호
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• pp.411-415
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• 2000

To be able to work safely and efficiency, the Threshold Limit Values (TLV) for work in the heat are widely used. Since these TLV are only applicable to workers in regular clothing, TLV should be adjusted when applied to the asbestos removal workers who wear extra impermeable protective clothing. Although abbreviated guidelines for heat stress exposure have been proposed, literature advocating their use in the asbestos removal industry is limited. Therefore, we planed a survey to evaluate the workload of asbestos abatement workers in summer, and an experiment with climatic chambers to evaluate the effects of resting in a cool environment between work periods. From these studies, we got following conclusions. There is a high risk of suffering from heat illness by asbestos abatement work in summer in Japan. It is proposed to create a cool room inside the workplace of asbestos abatement work to reduce thermal stress.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3413-3417
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• 2007

In recent semiconductor manufacturing clean rooms, air washers are used to remove airborne gaseous contaminants such as $NH_3$, SOx and organic gases from the outdoor air introduced into clean room. In the present study, an experiment was carried out to examine the improvement of removal efficiency for the gaseous contaminants. In order to improve the gas removal efficiency, a hot water contact heat exchanger was installed upstream of the air washer to heat and humidify the incoming outdoor air before entering the air washer.

• Architectural research
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• 제10권1호
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• pp.1-11
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• 2008

A Steel column with damaged spray-applied fire resistive material (SFRM) may exhibit reduced structural performance due to the effects of elevated temperature during fire events. Thus, the fire load behavior of steel columns with removed or reduced SFRM needs to be examined to predict the structural damage by fire. FEM analyses were performed for the flange thinning removal models in which the SFRM was reduced as a constant strip in thickness at the top flange of the column. The temperature results for all models obtained from the heat transfer analyses were included as an initial condition in the FEM structural analyses. In this study, the results of analysis show that even small remnants of SFRM led to an effective reduction of temperature at any given fire duration, and improved significantly the axial load capacity of a column as compared to the complete removal cases of SFRM.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.347-350
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• 2005

The strength level for removal of lining concrete in tunnel is increased from 2.94MPa to 4.9MPa in 2004. This result in the increase of concrete curing time, and construction time would be delayed. In this study, in order to improve the efficiency of construction cycle and satisfy the strength criterion, a curing method is adopted, which is considering the hydration heat in the lining concrete member. As a result, it is shown that the concrete curing time for form removal is about 20hrs without the adjustment of concrete mix design. And construction cycle time is not changed compared to that before the change of strength criterion.