• Nuclear Engineering and Technology
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• 제32권2호
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• pp.108-127
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• 2000

Hot leg break LBLOCA(Large Break LOCA) had a potential to be a containment maximum pressure accident in YGN3&4, which was induced from excessive conservatism in the CE analysis methodology of mass and energy release. This study conducted mass and energy release experiment for the hot leg break LBLOCA during post blowdown with an integral test facility, SNUF(Seoul National University Facility). This facility simulated YGN 3&4 with volume ratio of 1/1140 based on Ishii's three level scaling. Experiment showed that SI(Safety Injection) water refilled cold leg first and core later. SI water was vaporized in the core, which resulted in the repressurization of reactor. This increase of pressure drove the water in cold leg to flow up half height of U tubes. However, since the water was drained back soon, the release through the SG side broken section by evaporation was negligibly small. This study also provided experimental assessment of RELAP5 results by KAERI for the release through the SG side broken section.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.772-777
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• 1997

Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and in the hot leg and SG during the TMLB' scenrio. The objective of this study is to develop a natural circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models.

• 한국축산식품학회지
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• 제31권5호
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• pp.676-683
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• 2011

The aim of this study was to compare the physicochemical changes of hot-boned chicken breast and leg muscles. Chicken breast and leg muscles from 56 broilers were excised within a 15 min post-mortem (PM) and stored at $20^{\circ}C$. Physicochemical traits were determined at 0.5, 6, 12, and 24 h PM. The ultimate pH of leg muscle was higher than that of breast muscle (p<0.05). The content of glycogen in the breast muscle was relatively higher than that in the leg muscle until 6 h PM (p<0.05). R-values showing rigor mortis of breast and leg muscles were completed after or before 6 h PM. Breast muscle had less cooking loss than leg muscle (p<0.05). Drip loss did not significantly differ between breast and leg muscles with the exception of that at 6 h PM. The sarcomere length of leg muscle was relatively longer than that of breast muscle (p<0.05). The MFI of leg muscle was significantly lower than that of breast muscle (p<0.05). The shear force of leg muscle was lower than that of breast muscle at 6 and 12 h PM (p<0.05); however, that of both muscles did not significantly differ at 24 h PM.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.29-35
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• 1996

For the Reactor Coolant System(RCS) flow rate measurement by the secondary calorimetric heat balance method, the coolant temperature of the hot leg is needed. Several Resistance Temperature Detectors(RTD) are installed in the hot leg to measure the temperature, but the average value of RTDs does not correctly represent the energy-averaged(bulk) temperature because of the thermal stratification phenomenon. Therefore some correction is introduced to predict the bulk temperature, but the correction inevitably contains uncertainty because the stratification is not defined well quantitatively yet. Therefore a large uncertainty for the correction has been used for the conservative estimation. But unrealistically large uncertainty causes degradation of the measurement method and yields difficulty to meet the acceptance criterion in start-up flow measurement test. In this paper, an analytical estimation is made on the correction and the related uncertainty using the measured hot leg velocity profile of System 80 reactor flow model test and the measured temperatures of YGN 3&4 and PVNGS 1&2 start-up tests. The results reveal that the magnitude of the correction uncertainty is much smaller than that used in the previous design. Therefore, the confidence on the flow rate measurement method can be improved and the difficulty in start-up flow measurement test can be lessened if the smaller correction uncertainty obtained through this estimation is applied.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.405-410
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• 1996

New methodology for mass and energy release assessment in LBLOCA post blowdown is needed and, first of all, the phenomenologically improved and quantitative assessments through experiment are essential. For tile experiment of a hot leg break LBLOCA in post blowdown, the test facility was set and its feature is that tile broken hot leg has two broken sections in the tore side and in the SG side respectively and a separation valve between the two in order to measure the release rate dividedly. Specially it was focused on whether the mass release through the SG side broken section happened or not. The mass release through the core side broken section is dependent on tile safety injection flow and that through the SG side broken section varies depending on several factors. The principal factor is the primary system pressure and the subfactors such as SI flow rate, SI temperature and initial primary pressure, may contribute, too.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.829-841
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• 2018

An experiment was conducted for the OECD/NEA ROSA-2 Project using the large-scale test facility (LSTF), which simulated a 17% hot leg intermediate-break loss-of-coolant accident in a pressurized water reactor (PWR). In the LSTF test, core uncovery started simultaneously with liquid level drop in crossover leg downflow-side before loop seal clearing, and water remaining occurred on the upper core plate in the upper plenum. Results of the uncertainty analysis with RELAP5/MOD3.3 code clarified the influences of the combination of multiple uncertain parameters on peak cladding temperature within the defined uncertain ranges. For studying the scaling problems to extrapolate thermal-hydraulic phenomena observed in scaled-down facilities, an experiment was performed for the OECD/NEA PKL-3 Project with the Primarkreislaufe Versuchsanlage (PKL), as a counterpart to a previous LSTF test. The LSTF test simulated a PWR 1% hot leg small-break loss-of-coolant accident with steam generator secondary-side depressurization as an accident management measure and nitrogen gas inflow. Some discrepancies appeared between the LSTF and PKL test results for the primary pressure, the core collapsed liquid level, and the cladding surface temperature probably due to effects of differences between the LSTF and the PKL in configuration, geometry, and volumetric size.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.693-694
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• 2005

• Nuclear Engineering and Technology
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• 제29권3호
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• pp.229-239
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• 1997

To investigate the realistic behavior of mass and energy release and resultant containment response during large break Loss of Coolant accident (LOCA), analyses are performed for Yonggwang (YGN) 3&4 nuclear power plants by using a merged version of RELAP5/CONTEMPT4 computer code. Comparative analyses by using conservative design computer codes are also peformed. The break types analyzed are the double-ended guillotine breaks at the cold leg and hot leg. The design analysis resulted in containment peak pressure during post-blowdown phase for the cold leg break. However, the RELAP5/CONTEMPT4 analyses show that the containment pressure has a peak during blowdown phase, thereafter it decreases monotonously without the second port-blowdown peak. For the hot leg break, revised design analysis shows much lower pressure than that reported in YGN 3&4 final safety analysis report. The RELAP5/CONTEMPT4 analysis shoos similar trend and confirmed that the bypass flow through the broken loop steam generator during post-blowdown is negligibly small compared to that of cold leg break. The low pressure and temperature predicted tv realistic analysis presented in this paper suggest that the design analysis methodology contains substantial margin and it can be improved to provide benefit in investment protection, such as, relaxing plant technical specifications and reducing containment design pressure.

• 한국식품영양학회지
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• 제12권3호
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• pp.258-264
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• 1999

This study was carried out to investigate the status in weight loss yield of edible meat quality and free amino acid contents of the snow crab(Chionoectes japonicus) by steaming and various drying treat-ment. Change of body weight loss in steaming treatment sample were 20.48∼26.72% and yield of edible meat of steaming sample was higher than raw sample(p<0.05) The pH value was increased with steam-ing and drying and pH of trunk meat was more increased than leg meat. Volatile basic nitrogen(VBN) content of vacuum dried sample was highest and VBN of hot-air and freezing dried sample were about 10mg%. Content of vaccum dried sample wre 41.33 and 48,56mg%. Thirty kind of free amino acids dectected in the snow crab and changes of free amino acid in leg meat were markedly reduced by vacuum drying and the reducing ratio of leg meat by freeze drying was little. The major free amino acid of leg and trunk meat were 39.94% 46.78% respectively. The formation of flavor free amino acid in freezing dried sample were high but its hot-air aried sample were small.

• 한국식품영양과학회지
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• 제11권4호
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• pp.47-52
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• 1982

broiler의 가슴근육(筋肉)과 다리근육(筋肉)을 고온(高溫)$(30^{\circ}C)$과 저온(低溫)$(2^{\circ}C)$에 저장(貯藏)하였을때 저장기간(貯藏期間) 경과(經過)에 따른 무기물함량(無機物含量)과 사후(死後) 생화학적(生化學的) 고찰(考察)하였으며 가슴근육(筋肉)과 다리근육(筋肉)은 $2^{\circ}C$와 $30^{\circ}C$에 저장(貯藏)하면서 0.4.8. 20 32시간마다 실험분석(實驗分析)한 결과(結果)는 아래와 같다. (1) 다리근육(筋肉)과 가슴근육(筋肉)은 물리적조성(無機物組成)에 차이(差異)가 있다. (2) 전질소함량(全窒素含量)은 가슴근육(筋肉)과 다리근육(筋肉)이 저장온도(貯藏溫度)와 저장기간(貯藏期間)에 따라 변화(變化)의 유의차(有意差)가 인정(認定)되었다.(P<0.05) (3) 가슴근육(筋肉)의 인산(燐酸)(P<0.05), 마그네슘(P<0.05) 나트륨(P<0.025) 함량은 다리근육보다 높게 나타났으나 저장온도(貯藏溫度)나 기간(期間)에 따른 변화(變化)는 없었다. (4) 칼슘과 철함량(含量)은 근육(筋肉)의 부위(部位)에 따라서는 차이(差異)가 없으나 저장기간(貯藏期間)과 온도(溫度)에 있어서는 감소(減少)되었다.(P<0.01) (5) 나트륨은 여러 요인간(要因間)에는 유의차(有意差)가 없었으며 pH는 다리근육(筋肉)과 가슴근육간(筋肉間)에 유의차(有意差)가 인정(認定)되었다(P<0.05). 극한(極限) pH는 8시간에 보였으나 고온저장(高溫貯藏)한 가슴근육(筋肉)은 20시간(時間)에 보였다. 저온저장(低溫貯藏)한 가슴근육(筋肉)의 pH감소(減少)는 고온저장(高溫貯藏)한 가슴근육(筋肉)보다 빨랐다. (6) 가슴근육(筋肉)의 침입도(侵入度)는 다리근육(筋肉)보다 높았다(P<0.005) (7) 저온저장(貯藏)한 가슴근육(筋肉)과 고온저장(高溫貯藏)한 다리근육(筋肉)은 사후강직(死後强直)이 없었으며 저온저장(低溫貯藏)한 다리근육(筋肉)과 고온저장(高溫貯藏)한 가슴근육(筋肉)은 4시간에 사후강직(死後强直)이 발생(發生)하였다.