• Nuclear Engineering and Technology
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• v.50 no.2
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• pp.313-317
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• 2018

Licenses for the storage of spent nuclear fuel (SNF) and vitrified highly active waste in casks under dry conditions are limited to 40 years and have to be renewed for prolonged storage periods. If such a license renewal has to be expected since as in accordance with the new site selection procedure a final repository for spent fuel in Germany will not be available before the year 2050. For transport and possible unloading and loading in new casks for final storage, the integrity and the maintenance of the geometry of the cask's inventory is essential because the SNF rod cladding and the cladding of the vitrified highly active waste are stipulated as a barrier in the storage concept. For SNF, the cladding integrity is ensured currently by limiting the hoop stress and hoop strain as well as the maximum temperature to certain values for a 40-year storage period. For a prolonged storage period, other cladding degradation mechanisms such as inner and outer oxide layer formation, hydrogen pick up, irradiation damages in cladding material crystal structure, helium production from alpha decay, and long-term fission gas release may become leading effects driving degradation mechanisms that have to be discussed.

• Journal of the Korean Home Economics Association
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• v.42 no.1
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• pp.167-180
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• 2004

This study was carried out to investigate quality characteristics of chopped garlic stored at various temperature. Chopped garlic was stored at room temp.($25^{\circ}C$), refrigerator temp.($5^{\circ}C$) and frozen temp. ($-18^{\circ}C$) for 1, 2, 4, 8, 24, 48, 72 hours(room temp.) and 1, 3, 5, 7, 10, 15, 20, 30 days(refrigerator temp. and frozen temp.), respectively. Brown color, Hunter color value, vitamine C contents and flavor patterns by electronic noes of chopped garlic were measured. Fresh chopped garlic was used as control and garlic powder by hot air drying was used for comparisons. Brown color of chopped garlic increased with increasing storage time, and the intensity of that was reduced as following order such as chopped garlic stored at room temp., refrigerator temp. and frozen temp. Brown color of garlic powder was most dark amomg all the samples. The results of Hunter color value was consistent with then of brown color in chopped garlic, whereas those of garlic powder showed relatively low browning. Above results might be caused by the difference of measurement as only surface color was measured in Hunter color value unlike brown color. Vitamine C contents of chopped garlic decreased with increasing storage time, and in particular those stored at room temp. decreased markedly as retention of those stored at room temp. was 60％ of control after 1 day storage. Vitamine C retention of chopped garlic stored at refrigerator temp. was 78％ of control after 10 day storage and that stored at frozen temp. was 86％ of control after 30 day storage. At room temp., flavor pattern by electronic nose showed a difference between chopped garlic stored for 1hour and control, and showed occurrence of off odor after 1 day storage. Flavor pattern of garlic powder by electronic nose showed a mild flavor. Flavor patterns of chopped garlic stored at refrigerator temp. were similiar until 10 day storage, whereas those showed occurrence of volitile components after 15 day storage. Flavor patterns of chopped garlic stored at frozen temp. were similiar after 30 day storage, and especially those after 3 day storage were almost the same as control. Therefore it is desirable to store chopped garlic within 1 day at room temp. and within 10 days at refrigerator temp. And it is most desirable to store chopped garlic at frozen temp. as retention of quality characteristics was superior than other storage temp.

• Restorative Dentistry and Endodontics
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• v.29 no.3
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• pp.249-266
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• 2004

The purpose of this study was to determine whether pH and time has any influence on the degradation behavior of composite restoration by analyzing the leached monomers of dental composites qualitatively and quantitatively after storage in acetate buffer solution as a function of time using high performance liquid chromatography (HPLC) / mass spectrometer. Materials and Methods：Three commercial composite restorative resin materials (Z-250, Heliomolar and Aeliteflo) with different matrix structure and filler composition were studied. Thirty specimens (7mm $diameter{\times}2mm$ thick) of each material were prepared. The cured materials were stored in acetate buffer solution at different pH (4, 7) for 1, 7 and 45days. As a reference, samples of unpolymerized composite materials of each product were treated with methanol (10mg/ml). Identification of the various compounds was achieved by comparison of their mass spectra with those of reference compound, with literature data. and by their fragmentation patterns. Data were analysed statistically using ANOVA and Duncan's test. Results：1. Amounts of leached TEGDMA in Aeliteflo were significantly larger than those of UDMA in Z-250 and Heliomolar at experimental conditions of different storage time and pH variation (p<0.001). 2. As to comparison of the amounts of leached monomers per sorage time, amounts of leached TEGDMA in Aeliteflo and UDMA in Z-250 and Heliomolar were increased in the pH 4 solution more significantly than in the pH 7 solution after 1day, 7days and 45days, respectively (p<0.001). 3. In total amounts of all the leached monomers with storage times, the overall amounts of pH 4 extracts were larger than those of pH 7 extracts for all resin groups, but there was no significant difference (p>0.05).

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.26-38
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• 1997

The quality changes of hams and sausages in refrigerated storage were investigated. Seven types of hams and six types of sausages produced in Korea were collected from markets and stored at 1$0^{\circ}C$ according to the Food Code of Korea, and then chemical, microbiological, textural and sensory characteristics were evaluated at 30, 40 and 50 days. The proximal analysis showed considerable variation in fat with less variation in moisture and protein. The pH values of hams and sausages slightly changed with no consistent difference. Water activity values of all samples except one type of sausage were consistent over time in refrigerated storage. No purge losses of hams were observed except two types of samples in the intial stage. Several types of sausages showed purge losses with no consistency and one type of sausage showed consistent purge losses (0.44~11.29%) during the storage. The volatile basic nitrogen (VBN) content of hams and sausages was still within 20 mg% (Standard and Specification of Korea) on the 50th day, although the VBN of all samples significantly increased over time (p<0.05). The thiobarbituric acid (TBA) values of hams and sausages were well below 1.0 during the storage, although the TBA values of all samples significantly increased (p<0.05). However it was noticed that one type of ham and two types of sausages showed TBA values of 0.945, 0.928 and 0.978, respectively. All the standard plate counts (SPCs) of hams during the storage period showed a level below 30 CFU/g except one type of sample with 103 CFU/g at 50 days. All the SPCs of sausages showed a level below 50 CFU/g except one type of sample with 102 CFU/g and two types of samples with 104 CFU/g on the 50th day. Coliform groups were not counted in all samples during the storage. Instrumental texture analysis showed that springiness, cohesiveness, chewiness, gumminess and adhesiveness slightly changed with no consistent difference. The hardness of the hams showed a decreasing tendency, and the hardness of the sausages an increasing tendency with no significant difference. Sensory evaluation for color, flavor, taste, texture and overall acceptability showed decreasing tendencies over time (p<0.05). The scores of the five sensory characteristics maintained the medium level of quality at the termination of the experiment. Although the results indicated that the ham and sausage samples were acceptable after the 50 days' storage at 1$0^{\circ}C$, the shelf-life of the samples should be determined considering the rapid growth of bacteria and the high TBA values at 50 days.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.92-100
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• 2015

For the purpose of improving the efficiency of the radiation impact assessment of dry interim storage facilities for the spent nuclear fuel of pressurized water reactors (PWRs), radiation impact assessment was performed after the application of sensitivity assessment according to the radiation source term designation method, development of a 2-step calculation technique, and cooling time credit. The present study successively designated radiation source terms in accordance with the cask arrangement order in the shielding building, assessed sensitivity, which affects direct dose, and confirmed that the radiation dosage of the external walls of the shielding building was dominantly affected by the two columns closest to the internal walls. In addition, in the case in which shielding buildings were introduced into storage facilities, the present study established and assessed the 2-step calculation technique, which can reduce the immense computational analysis time. Consequently, results similar to those from existing calculations were derived in approximately half the analysis time. Finally, when radiation source terms were established by adding the storage period of the storage casks successively stored in the storage facilities and the cooling period of the spent nuclear fuel, the radiation dose of the external walls of the buildings was confirmed to be approximately 40% lower than the calculated values; the cooling period was established as being identical. The present study was conducted to improve the efficiency of the Monte Carlo shielding analysis method for radiation impact assessment of interim storage facilities. If reliability is improved through the assessment of more diverse cases, the results of the present study can be used for the design of storage facilities and the establishment of site boundary standards.

• Food Science and Preservation
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• v.13 no.5
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• pp.589-595
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• 2006

Vitamin U (5-methylmethionine) levels of Chinese cabbages at $4^{\circ}C$ were investigated to establish its physiological characteristics and also amino acids and sugars levels to find out their relationship with vitamin U were determined The levels of vitamin U showed different from parts of Chinese cabbages. The highest value was shown in outward leaf in Wineter Pride (12.70 mg/100 g fresh wt.) and core leaf in 55 Days cultivars (18.60 mg/100 g fresh wt.). leaf pare were 1.7-9.0 times higher in vitamin U levels than those in midribs in both cultivars. levels of vitamin U in stored Chinese cabbages increased with storage time. Moreover, two cultivars used far this experiment showed different pattern during storage. In Winter Pride, vitamin U levels sharply increased in leaf and midrib of cote part during storage. This value reached about 2.5 times for leaf and 4 times for midrib compared to the levels of initial storage time in core part In 55 Days cultivars, outward leaf showed an increased level of vitamin U of 1.8 times compared to that of 1 month storage time. Methionine known as a precursor of vitamin U synthesis did not showed clear relationship with vitamin U levels. Methionine was either not detected or at negligibly low levels in Chinese cabbages during storage. Methionine may not play a role in an increase of vitamin U during storage of Chinese cabbages at $4^{\circ}C$. No clear relationship of free amino acids and soluble sugars for vitamin U accumulation during storage of Chinese cabbages was shown in this study.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.158-167
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• 1987

The purpose of this study is to inquire and analyse the relation between traveltime (Tc) and watetshed physical characteristics surveyed such as river length (L), Lea, river main slope (s), base length of time area diagram, and storage constant (k). The results obtained in this study are as follows. The average widths of watersheds were with the range from 4.6 kilometers to 16.7 kilometers. The shape factors of main stream ranged from 0.08 to 0.37. The average slopes to main 8tream were within the range of 1.7-5.5 meter per kilometer. The relation between the base length and traveltime from S. C. S. method, Rational method, and RZIHA+KRAVEN method were derived $Tc=0.524{\times}1.35^c$ (r=0.98), $Tc=0.628{\times}1.339^c$, (r=0.98), $Tc=0.667{\times}1.342^c$ (r=0.97). The base length of the time-area diagram (c) for the IUH was derived as $c=0.9(\frac{L.L_{ca}}{\sqrt{s}})^{0.35}$ and correlation coefficient was 0.98 which defined a high significance. The storage constant K, derived in this study was $K=8.32+0.0213{\frac{L}{\sqrt{s}}}$ with correlation coefficient (0.96). The relation between storage Constant and conventional formula were figured out $Tc=0.0003{\times}3.323^k$ (r=0.97). $Tc=0.00045{\times}3.268^k$ (r=0.99) and $Tc=0.0004{\times}3.26^k$ (r=0.963). The base length (c) and storage constant (k) of time-Area Diagram were very important parts that determined traveltime for flood events. In the estimate of travel time for predicting flood volume, the formula of $Tc=0.524{\times}1.35^c$ that would be available to apply the Nak - Dong river watershed area and homogeneous watershed characteristics was found.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.582-589
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• 2010

As a part of the back-end fuel cycle, transportation of spent nuclear fuel (SNF) from nuclear power plants (NPPs) to a fuel storage facility is very important in establishing a nuclear fuel cycle. In Korea, the accumulated amount of SNF in the NPP pools is troublesome since the temporary storage facilities at these NPP pools are expected to be full of SNF within ten years. Therefore, Korea cannot help but plan for the construction of an interim storage facility to solve this problem in the near future. Especially, a decision on several factors, such as where the interim storage facility should be located, how many casks a transport ship can carry at a time and how many casks are initially required, affect the configuration of the transportation system. In order to analyze the various possible candidate scenarios, we assumed four cases for the interim storage facility location, three cases for the load capacity that a transport ship can carry and two cases for the total amount of casks used for transportation. First, this study considered the currently accumulated amount of SNF in Korea, and the amount of SNF generated from NPPs until all NPPs are shut down. Then, how much SNF per year must be transported from the NPPs to an interim storage facility was calculated during an assumed transportation period. Second, 24 candidate transportation scenarios were constructed by a combination of the decision factors. To construct viable yearly transportation schedules for the selected 24 scenarios, we created a spreadsheet program named TranScenario, which was developed by using MS EXCEL. TranScenario can help schedulers input shipping routes and allocate transportation casks. Also, TranScenario provides information on the cask distribution in the NPPs and in the interim storage facility automatically, by displaying it in real time according to the shipping routes, cask types and cask numbers that the user generates. Once a yearly transportation schedule is established, TranScenario provides some statistical information, such as the voyage time, the availability of the interim storage facility, the number of transported casks sent from the NPPs, and the number of transported casks received at the interim storage facility. By using this information, users can verify and validate a yearly transportation schedule. In this way, the 24 candidate scenarios could be constructed easily. Finally, these 24 scenarios were compared in terms of their operation cost.

• Journal of Environmental Health Sciences
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• v.30 no.1
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• pp.22-28
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• 2004

This study was performed to investigate the changes of amino nitrogen, total amino acids, free amino acids, and color of Korean traditional soy sauce (kan-jang) during the ripening and storage for 12 months and the characteristics of the changes. All of the preparation methods for soy sauce followed the recommendations of the Korea Food Research Institute. The components of soy sauce were analyzed at 0,6, and 12 months. The contents of amino nitrogen of soy sauce were significantly higher than that of soybeans or meju (soybean cakes) at the initial stage of storage (p<0.05), and decreased during the storage. The content of total amino acids of soybean sauce was significantly lower than that of soybeans, and the content of free amino acids was higher than that of soybeans (p<0.05). The contents of total and free amino acids decreased in soy sauce after 12 months of storage (p<0.05). The composition of total and free amino acids and their ratios of soy sauce were changed during the storage. The ratios of free to total amino acids of soybeans, meju, and soy sauce were 0.8％, 17.3％, and 53.1-59.8％, respectively. Glutamic acid, which represents the savory taste, was detected the most abundantly in soy sauce during the storage. The ratios of free to total amino acids of glutamic acid were 42.9-59.5％ in soy sauce. Lightness of Hunter color of soy sauce decreased over time (p<0.05). This study indicates that the ratios of free to total amino acids of soy sauce were much higher than those of soybeans, although its contents of total amino acids were much lower than those of soybeans. This study also indicates that this comes from the preparation and fermentation of meju. It was suspected that the organoleptic characteristics of soy sauce derived from the amino nitrogen, amino acids, and color might be inferior over 1 year of storage time. However, more detailed research should be conducted to interpretate this characteristics more accurately.

• Restorative Dentistry and Endodontics
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• v.42 no.4
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• pp.309-315
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• 2017

Objectives: This study assessed the effect of water storage on the flexural strength (FS) of low shrinkage composites. Materials and Methods: A total of 165 bar-shaped specimens ($2{\times}2{\times}25mm$) were fabricated of 2 low shrinkage composites (Filtek P90 [3M ESPE], GC Kalore [GC International]) and a conventional methacrylate-based composite (Filtek Z250 [3M ESPE]). The specimens were subjected to 3-point bending test at 6 time intervals, namely: immediately after curing, at 24 hours, 1 week, 1 month, 6 months, and 1 year following storage in wet and dry conditions. The FS of the specimens were measured by applying compressive load at a crosshead speed of 1.0 mm/min. Data was analyzed using 3-way analysis of variance (ANOVA) and Tukey's test. Results: Three-way ANOVA revealed significant interactions between time, type of composite, and storage condition (p = 0.001). Tukey's multiple comparison test revealed significant reductions in FS of all composites after 6 months and 1 year of storage in distilled water compared to dry condition. Conclusions: Filtek P90 showed the highest and GC Kalore showed the lowest FS after 1 year storage in distilled water. The immediate high strength of Filtek Z250 significantly decreased at 1 year and its final value was lower than that of Filtek P90.