• 한국환경농학회지
• /
• 제27권4호
• /
• pp.456-459
• /
• 2008

Quality of rice grain changes during dry storage with internal physiological changes and external injury by organism. Storage rice changes by condition with respiration via variable temperature, hydrolysis enzyme reaction, lipid peroxidation occurs with change of palatability. During dry storage, physiological change with protein variation pattern was examined by image analysis on proteomic technology. Analysis revealed that protein activity had no change store at room temperature and store at $40^{\circ}C$, but decreased store at $60^{\circ}C$. Analysis of variable hydrophobic protein pattern revealed that protein activity of beta-tubulin, protein disulfide isomerase, vacuolar ATPase b subunit, globulin was not significantly decreased all dry and store condition. However, heat shock protein 70, and glutathione transferase was significantly decreased when rice dried at $60^{\circ}C$ compared with room temperature and $40^{\circ}C$ dry condition.

• Nuclear Engineering and Technology
• /
• 제39권2호
• /
• pp.143-148
• /
• 2007

Spent nuclear fuel generated at nuclear power plants must be safely stored during interim storage periods. A dry storage cask to safely store the spent nuclear fuel should be able to adequately emit the decay heat from the spent nuclear fuel. Therefore, heat removal tests using a half scale dry storage cask have been performed to estimate the heat transfer characteristics of a dry storage cask under normal, off-normal, and accident conditions. In the normal condition, the heat transfer rate to an ambient atmosphere by convective air through a passive heat removal system reached 83%. Accordingly, the passive heat removal system is designed well and works adequately. In the off-normal condition, the influence of a half blockage in the inlet on the temperature appears minimal. In the accident condition, the temperature rose for 12 hours after the accident, but the temperature rise steadied after 36 hours.

• Nuclear Engineering and Technology
• /
• 제45권1호
• /
• pp.115-124
• /
• 2013

Among the several options to solve PWR spent fuel accumulation problem in Korea, the dry storage method could be the most realistic and applicable solution in the near future. As the basic objectives of dry storage are to prevent a gross rupture of spent fuel during operation and to keep its retrievability until transportation, at the same time the importance of a spent fuel integrity evaluation that can estimate its condition at the final stage of dry storage is very high. According to the national need and technology progress, two representative nations of spent fuel dry storage, the USA and Japan, have established different system temperature criteria, which is the only controllable factor in a dry storage system. However, there are no technical criteria for this evaluation in Korea yet, it is necessary to review the previously well-organized methodologies of advanced countries and to set up our own domestic evaluation direction due to the nation's need for dry storage. To satisfy this necessity, building a domestic spent fuel test database should be the first step. Based on those data, it is highly recommended to compare domestic data range with foreign results, to build our own criteria, and to expand on evaluation work into recently issued integrity problems by using a comprehensive integrity evaluation code.

• 방사성폐기물학회지
• /
• 제19권2호
• /
• pp.205-214
• /
• 2021

Currently, the interim storage pools of spent fuels in South Korea are expected to become saturated from 2024. It is required to prepare an operation plan of a domestic dry storage facility during a long-term period, with the researches on safety evaluation methods. This study modified the FRAPCON code to predict the spent fuel integrity evaluation such as the axial cladding temperature, the hoop stress and hydrogen distribution in dry storage. The cladding temperature in dry storage was calculated using the COBRA-SFS code with the burnup information which was calculated using the FRAPCON code. The hoop stress was calculated using the ideal gas equation with spent fuel information such as rod internal pressure. Numerical analysis method was used to calculate the degree of hydrogen diffusion according to the hydrogen concentration and temperature distribution during a dry storage period. Before 50 years of dry storage, the cladding temperature and hoop stress decreased rapidly. However, after 50 years, they decreased gradually and the cladding temperature was below 400 K. The initial temperature distribution and hydrogen concentration showed a parabolic line, but hydrogen was transferred by the hydrogen concentration and temperature gradient over time.

• 한국약용작물학회지
• /
• 제27권6호
• /
• pp.390-396
• /
• 2019

Background: Usually ginseng seeds are sown during autumn and spring. Sowing in spring often results in poorer seedling establishment than in autumn. One of the reasons for poor germination could be cold-treatment condition for breakage of physiological dormancy during winter. Here we tested the effects of storage temperature used during cold treatment on germination. Methods and Results: Germination properties were observed after dehiscent seeds were stored as wet and dry at 2℃, -2℃, -3.5℃ and alternating temperature (AT). Seed dryness and storage temperature affected germination properties (p < 0.01). Wet and AT condition germinated highest, and wet and -3.5℃ condition germinated lowest, which was 91.2% and 1.4% respectively. Mean germination time (MGT) of the wet and AT condition was faster than other treatments at 2.4 days, and the dry and -2℃ condition was the longest. Germination performance index (GPI) was highest for wet and AT condition (37.7%) and the lowest for wet and -3.5℃ condition (0.5%). The growth of above-ground and below-ground were the best for wet and 2℃ condition, and wet seeds showed better growth than dry seeds (p < 0.01). Conclusions: For cold treatment, ginseng seeds may not be stored below -2℃ for successful germination during spring sowing.

• 방사선산업학회지
• /
• 제18권2호
• /
• pp.133-140
• /
• 2024

The Korean 2^nd basic plan for management of high-level radioactive waste presented a plan to manage spent nuclear fuel through dry storage facilities in NPP on-site. For the construction and operation of the facility, it is necessary to develop the monitoring system of the integrity of spent nuclear fuel before operation. NUREG-1536 recommends that the theoretical cask array, typically in the 2×10 array, should account for shadowing effect among the dry storage casks. The objective of this study was to evaluate neutron flux accounting for shadowing effect among dry storage casks. The neutron release rate was evaluated using ORIGEN based on the design basis fuel condition. And the simulation of dry storage casks and evaluation of the shadowing effect were performed using MCNP. Shadowing effect of other dry storage casks was the highest at the center of the dry storage facility of the 2×10 array compared with the outside of the cask. The shadowing effect of neutron flux on the surface among the metal casks was approximately 18% at point 1, 23% at point 2, and 43% at point 3. For the concrete casks, the shadowing effect of neutron flux on the surface was approximately 46% at point 1, 51% at point 2, and 52% at point 3. This means that correction is necessary to monitor the integrity of spent nuclear fuel in each dry storage cask through evaluation of shadowing effect. The results of this study will be used for comparative analysis of neutron measurement data from spent nuclear fuels in dry storage cask. Additionally, the neutron flux evaluation procedure used in this study could be used as the basic data of safety assessment of dry storage cask and development of safety guide.

• 방사성폐기물학회지
• /
• 제15권2호
• /
• pp.135-149
• /
• 2017

사용후핵연료 건식저장의 실증연구는 건식저장 시스템의 안전성과 사용후핵연료의 저장 건전성 평가를 위한 확증적인 데이터 생산을 위하여 수행되어 왔다. 사용후핵연료의 건식저장을 가장 먼저 시작하였고 핵연료 건전성에 대한 법적 요건이 엄격하게 제시되어 있는 미국에서는 건식저장의 개시, 인허가 갱신을 위하여 주목할만한 몇몇 실증연구 프로그램을 운영한 바 있다. 건식저장 초기 단계에 건식저장 시스템 성능 검증 목적으로 실증연구가 수행된 바 있으며 저연소도 사용후핵연료의 건식저장 인허가 갱신을 위하여 건식저장 특성평가 프로젝트를 진행한 바 있다. 현재는 고연소도 사용후핵연료 인허가 연장을 위한 실증연구가 진행 중이며 이 연구는 향후 최소 10년이상 진행될 것으로 예상된다. 건식저장을 본격적으로 시작하지 않은 우리나라에서는 미국에서 진행해온 이러한 건식저장 실증연구가 훌륭한 타산지석이 될 것으로 생각되며 이에 본 논문에서는 미국의 건식저장 실증연구 프로그램의 과거와 현재를 분석하고 우리나라에서 진행할 필요가 있다고 사료되는 실증연구에 대한 제언을 담았다.

• Nuclear Engineering and Technology
• /
• 제45권4호
• /
• pp.421-426
• /
• 2013

The need for extended storage of used nuclear fuel is increasing globally as disposition schedules for used fuel are pushed further into the future. This is creating a situation where dry storage of used fuel may need to be extended beyond normal regulatory licensing periods. While it is generally accepted that used fuel in dry storage will remain in a safe condition, there is little data that demonstrate used fuel performance in dry storage environments for long periods of time. This is especially true for high burnup used fuel. This paper discusses a technical approach that defines a process that develops the technical basis for demonstrating the safety of used fuel over extended periods of time.

• 한국포장학회지
• /
• 제23권1호
• /
• pp.27-36
• /
• 2017

오리엔탈 나리 '시베리아'의 건식저장 기간에 따른 절화 보존 시 수분함량 변화와 절화수명을 구명하고자 하였다. 본 실험에서 저장 기간에 따라 저온 저장($5^{\circ}C$)을 한 다음 절화수명에 관계된 수분 및 품질 변화와 개화 정도를 검토하여 '시베리아' 나리의 절화 수확 후 관리 기술에 관계된 기본적인 자료를 얻고자 하였다. '시베리아' 나리를 채화하여 저온에서 건식저장 기간에 따라 3일, 6일, 12일한 후 절화보존 동안에 생체중 변화, 수분균형, 개화정도 등을 조사하였으며 대조구로서 상온 건식저장과 비교하였다. 저온 건식저장 후에 '시베리아' 나리의 수분함량은 건식저장 기간에 영향을 받아 저장하는 기간이 짧을수록 높아져 저장 3일이 다른 처리구보다 높아지는 경향을 보였다. 꽃의 수분함량은 절화보존 시 지속적으로 증가하는데, 저장 기간이 짧을수록 수분이 높게 유지되었다. 생체중 변화는 건식저장 기간에 영향을 받아 저장 기간이 짧았던 것에서 생체중의 증가 정도가 컸으며 음(-)의 값에 이르는 기간이 늦어지는 것으로 나타났다. 또한 절화보존 시 생체중 변화는 저온 건식저장 3일이 생체중 증가 정도가 완만하게 변하며 수분균형도 8일째에 음(-)의 값에 도달하는 것으로 나타났다. 그러나 저장 온도 차이에 따른 생체중 변화는 상온에서 저장한 절화가 저온저장보다 증감 정도가 더 빠른 것으로 나타났다. 개화정도는 '시베리아' 나리의 건식저장 기간이 길어질수록 개화시기가 빨라지며, 절화가 빨리 시들어 상품으로써 유지 기간이 짧아졌다. 개화상태를 비교해 보면 3일 저온 건식저장이 다른 처리보다 개화하는 속도가 늦었으나 절화수명은 다른 처리구보다 길게 나타났다. '시베리아' 나리의 저온 건식저장은 저장 기간이 짧을수록 저장 후 수분함량이 높고 수분 균형값이 음(-)에 늦게 도달하였으며 개화상태가 좋고 절화수명도 길어지는 것으로 나타났다. '시베리아' 나리는 건식저장을 통한 작물체내 수분 함량 감소가 절화보존 시 개화 특성에도 영향을 미쳐 저장기간이 길수록 절화수명이 감소하여 상품 가치를 떨어뜨렸다. '시베리아' 나리 절화를 소비자가 이용 시, 상품 가치 유지를 위해서는 기존 결과의 6일 동안 저온 건식저장도 절화수명을 단축시키므로 저장 기간을 최소화하는 것이 절화 품질 유지를 위해 바람직하다고 판단된다.

• 터널과지하공간
• /
• 제7권2호
• /
• pp.91-99
• /
• 1997

To stabilize the energy price, the more storage facilities of energy are required and among the storage methods of LPG and LNG, the method of storage at low temperature under normal confining pressure is considered. It is needed to understand the mechanical and thermal characteristics of rock under temperature variation so that the behaviors of rock can be predicted. In this paper, the variation of the rock charateristics of the Hwangdeung granite and the Boryung sandstone is studied at low temperature. The mechanical characteristics of rock under low temperatures are that as temperature decreased, unaxial compression strength and Young's modulus increased for Hwangdeung granite; strength and Young's modulus in wet condition were greater than those in dry condition. In the case of Boryung sandstone, as temperature decreases unaxial compression strength and Young's modulus increase but decrease below -10$0^{\circ}C$ in dry condition and below -16$0^{\circ}C$ in wet condtion. The mechanical characteristics of rock after cooling to previous temperature and thawing are that uniaxial compression strength and Young's modulus decrease as temperature decreases. Uniaxial compression strength and Young's modulus in wet conditon decrease more than those in dry condition. Brazilian tension strength decreases as temperature decreases.