The concrete silo dry storage system, which has been in operation at the Wolsong NPP site since 1992, consists of a concrete structure, a steel liner plate in the inner space, and a fuel basket. The silo system’s concrete structure must maintain structural integrity as well as adequate radiation shielding performance against the high radioactivity of spent nuclear fuel stored inside the storage system. The concrete structure is directly exposed to the external climatic environment in the storage facility and can be expected to deteriorate over time owing to the heat of spent nuclear fuel, as well as particularly cracks in the concrete structure. These cracks may reduce the radiation shielding performance of the concrete structure, potentially exceeding the silo system’s allowable radiation dose rate limits. For specimens with the same composition and physical properties as silo’s concrete structures, cracks were forcibly generated and then irradiated to measure the change in radiation dose rate to examine the effect of cracks in concrete structures on radiation shielding performance, and in the current state, the silo system maintains radiation shielding performance.

The 300 concrete silo systems installed and operated at the site of Wolsong nuclear power plant (NPP) have been storing CANDU spent nuclear fuel (SNF) under dry conditions since 1992. The dry storage system must be operated safely until SNF is delivered to an interim storage facility or final repository located outside the NPP in accordance with the SNF management policy of the country. The silo dry storage system consists of a concrete structure, liner steel plate in the inner cavity, and fuel basket. Because the components of the silo system are exposed to high energy radiation owing to the high radioactivity of SNF inside, the effects of irradiation during long-term storage must be analyzed. To this end, material specimens of each component were manufactured and subjected to irradiation and strength tests, and mechanical characteristics before and after irradiation were examined. Notably, the mechanical characteristics of the main components of the silo system were affected by irradiation during the storage of spent fuel. The test results will be used to evaluate the long-term behavior of silo systems in the future.

This study is in order to the effect of 1-methlycyclopropene (1-MCP) treatment and film package as modified atmosphere packaging (MAP) on the changes in fruit quality factors of 'Daehong' peaches during cold storage. The concentrations of 1-MCP were treated at 1μL·L-1 and 2μL·L-1, and peaches in film package were stored for 28 days in cold storage at 5±1°C and 85±5% RH. The fruits stored carton box were used as a control of MAP, and 1-MCP free fruits were used as the control of both packages. Rate of fresh weight loss during storage was not significantly different between groups with and without 1-MCP treatment, but was higher in the box package than in the MAP. The control group had a higher incidence of both gases with the 1-MCP treatment group showing statistically significantly low. Carbon dioxide in the package was lowered by about 12% compared to the non-treated group, and the ethylene concentration was maintained at 1μL·L-1, showing a significance low compared to other treated groups. As the storage period elapsed, the firmness of 1-MCP and MAP treated fruits remained significant at 5-9% compared to the control group. Regardless of the packaging method Hunter a* values of exocarp and mesocarp were significantly higher in fruit treated with 1-MCP 1μL·L-1 treatment than in the control group, and anthocyanin was significantly higher in the fruit during the storage period, especially high in MAP. In summary, fruits of MAP group with 1-MCP 1μL·L-1 had rate of lower respiration and ethylene production, and little changes in firmness, Hunter a* values of exo-carp and meso-carp, and anthocyanin, which is considered the most suitable method for preserving postharvest quality of the peach cultivar during the storage.

Plasma polymerized Styrene thin films were used as a memory layer in a memory device. As for the memory layer, a ppS thin films were used for the organic memory device and their charge storage characteristic was investigated comparatively, where the charge storage effect was evaluated by a hysteresis voltage. The organic memory device with ppS thin film of 30nm and 50nm as memory layer showed promising memory characteristics such as hysteresis voltage of 20V and 28V. The ppS revealed promising charge storage properties which confirms that an organic memory device without floating gate could be successfully implemented by using the ppS thin film as a memory layer.

Most of the spent nuclear fuel generated by domestic nuclear power plants (NPPs) is temporarily stored in wet storage which is spent fuel pool (SFP) at each site. Currently, in case of Kori Unit 2, about 93.6% of spent nuclear fuel is stored in SFP. Without clear disposal policy determined for spent nuclear fuel, the storage capacity in each nuclear power plant is expected to reach saturation within 2030. Currently, the SFP stores not only spent fuel but also various non-fuel assembly (NFA). NFA apply to all device and structures except for fuel rods inserted in nuclear fuel assembly. The representative NFA is control element driving mechanism (CEDM), in-core instrument (ICI), burnable poison, and neutral resources. Although these components are irradiated in the reactor, they do not emit high-temperature heat and high radiation like nuclear fuel, so if they are classified as intermediate level waste (ILW) and low level waste (LLW) and moved outside the SFP, positive effects such as securing spent fuel storage space and delaying saturation points can be obtained. Therefore, this study analyzes the status of spent fuel and Non Fuel Assembly (NFA) storage in SFP of domestic nuclear power plants. In addition, this study predict the amount of spent fuel and NFA that occur in the future. For example, this study predicts the percentage of current and future ICIs and control rods in the SFP when stored in the spent fuel storage rack. In addition, the positive effects of moving NFA outside the SFP is analyzed. In addition, NFA withdrawn from SFP is classified as ILW & LLW according to the classification criteria, and the treatment, storage, and disposal methods of NFA will be considered. The study on the treatment, storage, and disposal methods of NFA is planned to be conducted by applying the existing KN-12 & KN-18 containers and ILW & LLW containers being developed for decommissioning waste.

For Korean nuclear fuel cycle project, it is necessary to design and evaluate the integrity of spent fuel storage. For the design and evaluation of spent fuel storage, it is necessary to evaluate the properties of various materials used in spent fuel storage. The materials previously considered in the design of nuclear power plants were limited to static properties and were listed in design and manufacturing code and standards. However, for the evaluation of the storage containers in scenarios such as transportation and events, dynamic material property evaluations are required. Research on the dynamic properties of materials is generally conducted in the fields of automotive and aerospace, and most of the studies are on metal materials under sheet conditions. Since the structural materials of the storage containers for used nuclear fuel are mostly composed of thick materials, consideration should be given to property evaluation methodology and quantitative comparison. In this study, the mechanical properties of stainless steel material with canister application were evaluated according to the strain rate, and the crack resistance evaluation was also performed. It was confirmed the changes in strength and crack resistance according to the increase in strain rate and observed differences in microstructural hardening behavior.

In this study, we analyzed the effect of storage conditions on the survival of fungi in red pepper powder. Red pepper powder was inoculated with a total of six fungal species, namely Aspergillus terreus, Aspergillus flavus, Rhizopus microsporus, Aspergillus fumigatus, Aspergillus niger, and Aspergillus ochraceus at a final cell count of 4–6 log CFU/g. After inoculating the sterilized red pepper powder with fungi, we dried the powder on a clean bench and packaged it in zipper bags. Following drying, the water activity was 0.502±0.001. Subsequently, the red pepper powder inoculated with fungi was stored at -20oC, 5oC, 15oC, and 25oC. All six species of fungi perished the quickest at 25oC and survived for the longest (168 days) at -20oC. In summary, this study showed that fungi survive for an extended period in red pepper powder at -20oC and 5oC compared to 15oC and 25oC. Therefore, to prevent fungal contamination, red pepper powder should have a water activity below 0.6 and be stored in a zipper bag at room temperature.

수경 재배한 멜론의 생육과 수확 후 모의유통 시 품질 차이를 검토하였다. ‘루비볼춘추계’의 수경재배 된 멜론을 이용하여 저장 온도를 2℃와 5℃, 10℃, 20℃하여 모의유통 시 특성과 가용성고형물(SSC), 경도, 생체중 변화, 외관 등의 변화를 조사하였다. 멜론을 상온으로 유통하는 조건 하에서 저온저장에 따른 과실 특성을 본 연구에서 확인하였다. 멜론 저장 시 가용성고형물, 경도, 생체중, 외관이 저장온도에 따라 차이를 보였다. 가용성고형물은 멜론을 저온(2~5℃)에서 저장하여 모의유통 된 것이 상온(20℃)에서 다른 온도처리보다 높은 수준인 것으로 나타났다. 외관과 경도는 모의유통 중 저장 온도에 따른 영향이 지속적이지는 못하였지만 유통초기 저온(2~10℃) 저장이 외관 지수 및 경도 수치가 높은 경향이었다. 저장 온도에 따른 영향이 모의유통 시 계속 효과를 유지하지 못하여 국내 유통 시 이를 고려하여야 할 것이다. 본 연구 결과, 저장 온도에 따른 모의유통 중에 미치는 영향은 저장 직후 짧은 단기간에만 효과를 유지하여, 국내 유통 하에서 저장할 경우에는 바로 소비할 수 있도록 유도해야 할 것으로 생각된다.

Livestock production costs are heavily influenced by the cost of feed, The use of domestically grown forages is more desirable for livestock feed production. As part of this study, triticale, which is an extremely palatable and easily cultivable crop in Korea, was used to produce low moisture silage bales with lactic acid bacteria (LAB) and then stored for different periods. We examined the nutrient content of silage, such as crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF), as well as their organic acids, including lactic acid, acetic acid, butyric acid, at different storage periods. The nutrient content of silages, such as crude protein, ADF, and NDF, did not change significantly throughout storage periods. Organic acid data indicated that lactic acid concentrations increased with increasing moisture contents and storage periods up to nine months. However, further extending storage to 12 months resulted in a reduction in the lactic acid content of all silages as well as an increase in their pH. Based on the present results, it suggested that the production of low moisture silage with the LAB may be able to preserve and maintain its quality without altering its nutritional composition. Also, the lactate content of the silage remained significant for at least nine months.

The acoustic emission (AE) is proposed as a feasible method for the real-time monitoring of the structural damage evolution in concrete materials that are typically used in the storage of nuclear wastes. However, the characteristics of AE signals emitted from concrete structures subjected to various environmental conditions are poorly identified. Therefore, this study examines the AE characteristics of the concrete structures during uniaxial compression, where the storage temperature and immersion conditions of the concrete specimens varied from 15℃ to 75℃ and from completely dry to water-immersion, respectively. Compared with the dry specimens, the water-immersed specimens exhibited significantly reduced uniaxial compressive strengths by approximately 26%, total AE energy by approximately 90%, and max RA value by approximately 70%. As the treatment temperature increased, the strength and AE parameters, such as AE count, AE energy, and RA value, of the dry specimens increased; however, the temperature effect was only minimal for the immersed specimens. This study suggests that the AE technique can capture the mechanical damage evolution of concrete materials, but their AE characteristics can vary with respect to the storage conditions.

본 연구는 ‘스마트꿀’ 참외를 수확 후 ascorbic acid (AA) 및 salicylic acid (SA) 침지 처리와 PE film 처리가 저온저장(10℃) 중 과골 갈변 발생과 과실품질 변화에 미치는 영향을 조사하였다. 참외 과실의 저장기간 동안 과골 갈변 발생 정도는 무처리 과실의 경우 저장기간 동안 꾸준히 증가하여 저장 15일후 3.8 수준으로 증가하였으나, PE film 처리 과실은 저장 15일후 2.7 수준으로 낮은 과골 갈변 증상을 보였다. 참외 과실의 고유색을 나타내는 황색 과피의 황색도(b*)의 경우, 무처리 과실은 저장 15일 후 38.1로 감소하였으나, PE film 처리 과실은 저장 15일 후에도 39.8로 높은 황색도를 보였다. 흰색 과골 명도(L*)는 무처리 과실은 저장 15일 후 67.9로 감소하였으나, PE film 처리 과실은 72.9로 높게 유지되었다. 그리고 흰색 과골 적색도(a*)의 변화는 무처리 과실의 경우 저장 15일 후 1.0으로 증가하였나, PE film 처리 과실은 저장 15일 후에도 –1.4 이었으며, AA 처리 과실 역시 –0.5로 적색도 변화를 효율적으로 억제하였다. 가용성 고형물 함량은 무처리 과실은 저장기간 동안 점차 감소하였으나 PE film, AA 및 SA 처리 과실들은 거의 변화가 없었다. 그리고 과실 중량감소율은 무처리 과실은 저장 15일 후 1.98%이었으나, PE film 처리 과실은 1.33%로 가장 낮은 중량감소율을 나타내었다. 따라서 ‘스마트꿀’ 참외를 저장 및 유통할 때 과골 갈변 발생과 과색 및 품질의 변화를 억제하는데 PE film 처리가 효과를 보여 처리방법에 대한 효율적인 적용 방안을 모색할 필요가 있다고 판단되었다.

Post-slaughtering storage of pork meat is important to improve the flavor and texture profile. Although irradiation of meat improves the keeping qualities of red meat, less work was done on the effect of quality in irradiated pork leg meat during post-slaughtering storage. Therefore, this study was done to compare low dosages of single beam irradiation treated pork leg meat on eating quality parameters over the nontreated meat stored at different storage temperatures. Freshly slaughter pig carcasses were brought to the irradiation unit for treatment. Pork leg meat was treated at 2 kGy with single beam. Treated (2 kGy) and non-treated pork leg meat were kept in three different temperatures as 2, 10 and 25°C for 1, 3 and 5 days and analyzed for cooking loss, shear force, color and nitrogenous flavor compounds. Cooking loss in day 5 in irradiated pork leg (30.29) was significantly lower than the control (33.27) (p<0.05). Shear force of treated (1.93) and non-treated (1.29) pork leg meat after day 5 had significant difference (p<0.05). “L*” and “b*” values of pork leg meat had significant difference at day 5 compared non treated leg meat (p<0.05) whereas the “a*” value was increased with storage time and temperature. Hypoxanthine level was significantly lower in pork leg meat at day 5 in treated (16.07) and non-treated (24.59) meats at 25°C (p<0.05) whereas the changes in AMP, IMP and Inosine was not significantly difference (p>0.05). As conclusion, post-slaughtering storage and irradiation with single beam of 2 kGy could ensure the meat quality of leg pork at even higher storage temperatures, with cooking loss, tenderness, flavor and the color which will be benefited in the processing industry.

흑타리 UV-B조사시간에 따른 저장특성과 에르고스테 롤함량의 변화를 조사하였다. 중량감모율은 조사시간이 길어질수록 중량의 감소율이 증가하는 경향을 보였다. CO2/O2 조성의 경우 UV-B 조사시간이 길어질수록 증가하는 것으로 나타났다. ΔE는 Lightness와 Redness에서 30분처리와 무처리에서 큰 차이를 보이지 않았지만, Yellowness에서 무처리가 15분처리보다 2.7, 30분처리보다 1.6 높은 값이 나온 것을 확인할 수 있다. 경도에서도 마찬가지로 UV-B 조사시간이 길어지면 빠르게 물러지는 것을 확인할 수 있다. 에르고스테롤의 함량변화의 경우 30분처리가 무처리보다 약 2배 정도 높은 값이 나온 것을 볼 수 있었다. 전자현미경으로 관찰한 결과 UV-B조사시 간이 길어지면 길어질수록 세포벽이 부서지는 경향을 나타냈으며, 30분처리에 비해서 15분처리의 세포벽이 좀 더 양호한 것을 볼 수 있었다. 전체적인 결과로 보았을 때 UV-B 조사시간이 길어지면 저장특성이 나빠지며, 세포벽이 파괴되지만, 에르고스테롤의 함량이 증가하는 것으로 보인다. 하지만, 30분처리의 저장특성에 비해 15분처리의 저장특성이 높았으며, 에르고스테롤의 함량 차이가 크게 나지 않는 것으로 확인되었다. 따라서, UV-B 30분처리를 하게 되면 에르고스테롤의 함량은 증가하지만, 중량의 감소율이 증가하며, 색차값이 달라지며, 세포벽이 많이 부서지는 경향을 나타내었다. 추후 UV-B의 적정조사시간에 대한 추가적인 연구가 필요할 것으로 판단된다.

The purpose of this study was to investigate at how the quality of citron changed during storage as a result of the browning inhibitor treatment. In the browning inhibitor treatment, Vit.C, Vit.C+NaCl, Vit.C+NaCl+CD substances were used. As a result of investigating the browning degree, Vit.C+NaCl+CD showed the lowest value of 0.76 when stored for 12 weeks. The ΔE of the chromaticity value indicated that significant color change occurred when the value was high. As the Vit.C+NaCl+CD mixture showed the lowest value of 46.01 at 25℃, it was found that browning did not occur much compared to other treatments. The change in polyphenol oxidase (PPO) activity of citron increased as browning progressed. Among the browning inhibitor solutions, Vit.C+NaCl+CD solution showed the lowest value 118.8 u/g at 25℃ after 12 weeks. Based on these findings, it seems that CD mixing solution can be used as a citron browning inhibitor.