• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.595-598
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• 2005

The thermal performance of glass evacuated tube solar collectors are numerically and experimentally investigated. Four different shapes of solar collectors are considered and the performances of these solar collectors are compared. Dealing with a single collector tube, the effects of not only the shapes of the absorber tube but also the incidence angle of solar irradiation (beam radiation) on thermal performance of the collector are studied. However the solar irradiation consists of the beam radiation as well as the diffuse radiation. Also, the interference of solar irradiation and heat transfer interaction between the tubes exist in an actual solar collector. These effects are considered in this study experimentally and numerically the accuracy of the numerical model is verified by the experimental results. The result shows that the thermal performance of the absorber used a plate fin and U-tube is the best.

• 멤브레인
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• 제13권4호
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• pp.283-290
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• 2003

BSA 용액을 대상으로 한 dead-end 및 cross-flow 한외여과에서 막모듈에의 초음파 조사가 막성능 향상에 미치는 효과를 연구하였다. 이 결과 막모듈에의 간헐적 또는 연속적 초음파 조사는 막오염의 형성 억제 및 막오염 층의 제거에 상당한 효과가 있음이 확인되었다. 초음파 조사에 의한 막성능 향상 효과는 막오염을 크게 유발시키는 운전조건(도입액 농도와 TMP가 높고, 유량이 낮은 운전조건)일수록 더 컸으며, 막모듈에 초음파를 조사시키면 조사시키지 않은 경우와 비교할 때 dead-end 한외여과에서는 최대 약 1.9배, cross-flow 한외여과에서는 최대 약 1.5배의 투과플럭스 향상을 얻을 수 있었다.

• 방사성폐기물학회지
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• 제19권3호
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• pp.279-287
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• 2021

For application in nuclear decommissioning, underwater laser cutting studies were conducted on thick stainless-steel plates for various cutting directions using a 6 kW fiber laser. For cutting along the horizontal direction with horizontal laser irradiation, the maximum cutting speed was 110 mm·min^-1 for a 48 mm thick stainless-steel plate. For cutting along the vertical direction with horizontal laser irradiation, a maximum speed of 120 mm·min^-1 was obtained for the same thickness, which confirmed that the cutting performance was similar but slightly better. Moreover, when cutting with vertically downward laser irradiation, the maximum cutting speed was 120 mm·min^-1 for a plate of the same thickness. Thus, the cutting performance for vertical irradiation was nearly identical to that for horizontal irradiation. In conclusion, it was possible to cut thick stainless-steel plates regardless of the laser irradiation and cutting directions, although the assist gas rose up due to buoyancy. These observations are expected to benefit laser cutting procedures during the actual dismantling of nuclear facilities.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3176-3180
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• 2022

A gamma irradiator is a well-developed installation for gamma radiation sterilization. A "shuffle-dwell" mode is preferable for high dose applications. A novel configuration of a shuffle-dwell gamma irradiator is proposed to increase energy utilization and throughput, which would result in higher profitability. While the minimum distance between any irradiation position and each source pencil, the minimum distance between the neighboring irradiation positions and the size of source pencils are kept the same as the current configuration, the irradiation positions and source pencils are rearranged based on the fact that radiation is emitted in an isotropic fashion. The computational results suggest that the proposed configuration requires an 8.7% smaller area and exposes the product to 11.8% more gamma radiation in a 10.7% shorter irradiation time. In other words, the proposed configuration needs a smaller area and shorter irradiation time to have a better performance compared to the current shuffle-dwell gamma irradiator. Note that the claim is based primarily on an analytical calculation. Experimental and manufacturing among other practical considerations will be taken into account in the future work to exhaustively evaluate the performance of the proposed configuration and to compare it with that of the traditional configuration.

• 태양에너지
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• 제5권2호
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• pp.28-34
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• 1985

There are two kinds of irradiation intensity deviation, depending on time and position, on illuminated plane when thermal performance of solar collector is tested by using solar simulator. In this study we measured only position deviation of irradiation intensity using 45-cds photosensors and data acqusition system and found the point of average value. By this result we can improve the accuracy of irradiation measurement in indoor test of solar collector.

• Nuclear Engineering and Technology
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• 제45권3호
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• pp.311-322
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• 2013

High-Cr martensitic steel HT-9 is one of the candidate materials for advanced nuclear energy systems. Thanks to its excellent thermal conductivity and irradiation resistance, ferritic/martensitic steels such as HT-9 are considered for in-core applications of advanced nuclear reactors. The harsh neutron irradiation environments at the reactor core region pose a unique challenge for structural and cladding materials. Microstructural and microchemical changes resulting from displacement damage are anticipated for structural materials after prolonged neutron exposure. Consequently, various irradiation effects on the service performance of in-core materials need to be understood. In this work, the fundamentals of radiation damage and irradiation effects of the HT-9 martensitic steel are reviewed. The objective of this paper is to provide a background introduction of displacement damage, microstructural evolution, and subsequent effects on mechanical properties of the HT-9 martensitic steel under neutron irradiations. Mechanical test results of the irradiated HT-9 steel obtained from previous fast reactor and fusion programs are summarized along with the information of irradiated microstructure. This review can serve as a starting point for additional investigations on the in-core applications of ferritic/martensitic steels in advanced nuclear reactors.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1602-1611
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• 2021

A varying degree of eccentricity always exists in the initial configuration of a nuclear fuel rod. Its impact on traditional LWR fuel is limited as the radial gap closes relatively early during irradiation. However, the effect of misalignment is expected to be more relevant in rods with highly conductive fuels, large initial gaps and low conductivity filling gases. In this paper, we study similar characteristics in the experimental setup of two fuel disc irradiation campaigns carried out in the OECD Halden Boiling Water Reactor. Using the multi-dimensional fuel performance code OFFBEAT, we combine 2-D axisymmetric and 3-D simulations to investigate the effect of eccentricity on the fuel temperature distribution. At the same time, we illustrate how the advent of modern tools with multi-dimensional capabilities might further improve the design and interpretation of in-pile separate-effect tests and we outline the potential of such an analysis for upcoming experiments.

• Nuclear Engineering and Technology
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• 제45권7호
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• pp.847-858
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• 2013

Since 2001, a series of five irradiation test campaigns for atomized U-Mo dispersion fuel rods, KOMO-1, -2, -3, -4, and -5, has been conducted at HANARO (Korea) in order to develop high performance low enriched uranium dispersion fuel for research reactors. The KOMO irradiation tests provided valuable information on the irradiation behavior of U-Mo fuel that results from the distinct fuel design and irradiation conditions of the rod fuel for HANARO. Full size U-Mo dispersion fuel rods of 4-5 $g-U/cm^3$ were irradiated at a maximum linear power of approximately 105 kW/m up to 85% of the initial U-235 depletion burnup without breakaway swelling or fuel cladding failure. Electron probe microanalyses of the irradiated samples showed localized distribution of the silicon that was added in the matrix during fuel fabrication and confirmed its beneficial effect on interaction layer growth during irradiation. The modifications of U-Mo fuel particles by the addition of a ternary alloying element (Ti or Zr), additional protective coatings (silicide or nitride), and the use of larger fuel particles resulted in significantly reduced interaction layers between fuel particles and Al.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.179-182
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• 2006

The effect of electron beam irradiation on dye sensitized solar cell (DSSC) has been studied to examine degradation of DSSC. The high-energy electron beam irradiation affects on the materials and performance of dye sensitized solar cells. We have checked the effects of electron beam irradiation of $TiO_2$ substrate with and without dye adsorption on the photovoltaic performances of resulting DSSCS and also studied the structural and electrical properties of polymers after irradiation. All solar cells materials were irradiated by electron beams with an energy source of 2MeV at different dose rates of 60 kGy, 120 kGy 240 kGy and 900 kGy and then their photoelectrical parameters were measured at 1 sun $(100 mW/cm^2)$. It was shown that the efficiency of DSSC was decreased as increasing the dose of e-beam irradiation due to lowering in $TiO_2$ crystallinity, decomposition of dye and oxidation of FTO glasses. On the other hand, the performance of solid-state DSSC with polyethylene oxide based electrolyte was improved after irradiation of e-beam due to enhancement of its conductivity and breakage of crosslinking.

• Journal of Ceramic Processing Research
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• 제20권4호
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• pp.363-371
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• 2019

In this study, physical properties of normal concrete, magnetite concrete, EAF concrete, and EAF concrete with added iron powder were evaluated and a feasibility of radiation shielding is also evaluated through irradiation tests against X-rays and gamma-rays. While the unit weight of EAF concrete (3.21 t/㎥) appeared lower than that of magnetite concrete (3.50 t/㎥), the results in compressive strength of EAF concrete were greater than those in magnetite and normal concrete. While the radiation transmission rate of normal concrete reaches 26.0% in the X-ray irradiation test, only 6.0% and 9.0% of transmission rate were observed in magnetite concrete and linear relationship with unit volume weight and radiation shielding. In the gamma-ray irradiation test, the performance of EAF and magnetite concretes appeared to be similar. Through the results on the excellent physical properties and radiation shielding performance a potential applicability of EAF concrete to radiation shielding was verified.