• Tunnel and Underground Space
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• v.23 no.1
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• pp.13-30
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• 2013

Increase of pore fluid pressure resulting from injection of $CO_2$ may reactivate pre-existing faults, and the induced seismic activities can raise the safety issues such as seal integrity, restoration of storage capacity, and, in the worst case, removal of previously injected $CO_2$. Thus, fault stability and potential for $CO_2$ leakage need to be assessed at the stage of site selection and planning of injection pressure, based on the results of large-scale site investigations and numerical modeling for various scenarios. In this report, studies on the assessment of fault stability during injection of $CO_2$ were reviewed. The seismic activities associated with an artificial injection of fluids or a release of naturally trapped high-pressure fluids were first examined, and then site investigation methods for the magnitude and orientation of in situ stresses, the distribution and change of pore fluid pressure, and the location of faults were generally summarized. Recent research cases on possibility estimation of fault reactivation, prediction of seismic magnitude, and modeling of $CO_2$ leakage through a reactivated fault were presented.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.141-148
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• 1992

Field experiment was carried out to investigate the effect of plant growth regulator (PGR); IAA, GA, Kinetin to regrowth of sorghum and pearlmillet according to variety and plant growth stage. Kinetin application after cut increased tiller number and decreased dry weight of regrowth, but its application on sorghum stubble in water stress increased tiller number and leaf elongation rate, consequently increased regrowth dry weight. GA application reduced tiller production in both species, but tiller formation in pearlmillet was decreased more than in sorghum by promoting leaf elongation of old tiller. Nonstructural carbohydrate (NSC) of stubble during regrowth was consumed less at anthesis than at stem elongation stage because of senescence of tiller primordia. GA treatment reduced NSC content more than other PGR in both plant species, by consuming reserve NSC and stimulating rapid elongation of old tiller after cut. Dry matter increase during regrowth had high correlation with tiller number and tiller elongation a week after cut, while it did not have any correlation with NSC at cutting stage or with consumption of NSC during regrowth. Therefore, regrowth in sorghum and pearmillet must depend upon activity of tiller primordia more than upon amount of reserved NSC.

• Journal of Soil and Groundwater Environment
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• v.14 no.4
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• pp.33-44
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• 2009

Water curtain of an underground LPG storage cavern is a facility to prevent leakage of high pressure gases, for which groundwater should flow freely towards the cavern and groundwater level also must be stably maintained. In this study, in order to evaluate qualities of seepage water and surrounding groundwater of an underground LPG storage cavern in Yeosu, 4 rounds of samplings, field measurements and laboratory analyses (February, May, August, October of 2007) were conducted. According to field measurements, pH was weak acidic to neutral but it gradually increased with time. Electrical conductivity (EC) of groundwater near a salt stack showed very high values between 10.47 and 38.50 mS/cm. Dissolved oxygen (DO) showed a very wide range of 0.20~8.74 mg/L and a mean of oxidation-reduction potential (ORP) was 159 mV, which indicated an oxidized condition. Levels of $Fe^{2+}$ and $Mn^{2+}$ were mostly less than 3 mg/L. All of seepage waters showed a Na-Cl type while only groundwater near the salt stack showed a Na-Cl type with a high total dissolved solid. The other groundwaters exhibited typical $Ca-HCO_3$ types. Levels of aerobic bacteria were mostly very high (573-39,520 CFU/mL). Based on the analyses of these hydrochemistry and biological characteristics, it is concluded that there are no particular problems in groundwater and seepage water, which not causing a trouble in the cavern operation. However, both for control of bio-clogging and for sustainable operation of the water curtain system, a regular hydrochemical and microbiological monitoring is required for the seepage water and surrounding groundwater.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.167-183
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• 2023

Gases originated from the final SNF (spent nuclear fuel) disposal site are very mobile in the barrier and they may also affect the migration of radioactive nuclides generated from the SNF. Mechanisms of gas-nuclide migration in the multi-barrier and their influences on the safety of the disposal site should be understood before the construction of the final SNF disposal site. However, researches related to gas-nuclide coupled movement in the multi-barrier medium have been very little both at home and abroad. In this study, properties of gas generation and migration in the SNF disposal environment were reviewed through previous researches and their main mechanisms were summarized on the hydrogeological evolution stage of the SNF disposal site. Gas generation in the SNF disposal site was categorized into five origins such as the continuous nuclear fission of the SNS, the Cu-canister corrosion, the oxidation-reduction reaction, the microbial activity, and the inflow from the natural barriers. Migration scenarios of gas in porous medium of the multi-barrier in the SNF repository site were investigated through reviews for previous studies and several gas migration types including ① the free gas phase flow including visco-capillary two-phase flow, ② the advection and diffusion of dissolved gas in pore water, ③ dilatant two-phase flow, and ④ tensile fracture flow, were presented. Reviewed results in this study can support information to design the further research for the gas-nuclide migration in the repository site and to evaluate the safety of the Korean SNF disposal site in view points of gas migration in the multi-barrier.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.3
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• pp.266-271
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• 1991

The salted and dried mullet roe was manufactured by the conventional processing method. The processing conditions were the salting with soybean sauce of 10% NaCl, 1.2cm of thickness, 3m/sec of air velocity, 70% of RH and $20^{\circ}C$ of wind-drying temperature for 20 days. The fractional compositions of free and bound lipids were classified in neutral, Glyco - and phospholipids of the processed roe. The fatty acid content of glycolipids was measured during processing and storage. Major fatty acids of glycolipids were $C_{16:0},\;C_{18:1}\;and\;C_{18:2}$ whose total amount was 7.71mg/100mg occupying 77% of the total fatty acids of glycolipids. The ratio of unsaturated fatty acid to the saturated fatty acid of bound glycolipids was 2.09 and that of free glycolipids was as low as about 0.92. The rations of the polyenoic acids to the monoenoic acids were very low as 0.10-0.78. The essential fatty acids of bound glycolipids were 4.32mg/100mg and a very much decreased content of 1.46mg/100mg at 9 week storage time.

• Journal of the Korean Geographical Society
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• v.44 no.4
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• pp.429-446
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• 2009

To understand the sulfur flux and cycle in the forest catchment, the hydrological processes and chemical variation of soil solution, groundwater and stream water were analyzed at the Matsuzawa catchment located in the Kiryu Experimental Basin, Shiga Prefecture, central Japan. Unsaturated soil layer at the upper slope of catchment was the source area of ${SO_4}^{2-}$, and deep soil layer and groundwater were the sink zone of ${SO_4}^{2-}$. The vertical distribution of ${SO_4}^{2-}$ concentrations in groundwater affected seasonal variation of ${SO_4}^{2-}$ concentrations in stream water, as groundwater level changed. It is reasonable to assume that each hydrological processes in the forest catchment play an important roles in the retention and discharge of ${SO_4}^{2-}$.

• Clean Technology
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• v.17 no.4
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• pp.353-362
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• 2011

In our nature, the utilization of rainwater is essential for healthy water recirculation. This is one of the solutions of the increment of impermeability surface according to the development of new cities; this study of the improvement of rainwater quality has been carried on through the improvement of collecting and restoring system of rainwater. The southwestern region of Daejeon City, the rainwater coefficient of run off was 0.40 and this number had computed to 0.59 after the development. After filtration of rainwater, the heavy metal (Cu, As, Cr, Fe, Mn) contents level were lower than underground water. Moreover, collected rainwater showed better quality than underground water in following criteria; hardness, permanganate consumption quality, chloride, evaporation residue, sulfates and nitrate nitrogen. This water quality met the gray water quality standards. The rainwater quality was still suitable to use as bathroom flushing and gardening after 100 days of storage. This study proved that modification (installation of cover with gutter to existing rainwater collection system, proper filtering, and installation of underground storage tank) of collection system could improve quality of water and maintain this approximately 100 days.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Tunnel and Underground Space
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• v.24 no.3
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• pp.201-211
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• 2014

In the present study, the thermal performance of multiple rock caverns for large-scale thermal energy storage (TES) was numerically investigated for different separation distances between the caverns through heat transfer analysis using a computational fluid dynamics code, FLUENT. The thermal performance of multiple caverns was assessed in terms of the thermal stratification within the caverns and the heat loss to the surroundings, and the heating characteristics of the rock around the caverns were investigated. The results of numerical simulation showed that there was little difference in thermal performance between multiple TES caverns with different separation distances when the surrounding rock was less heated and it reached thermal steady-state, which represent the thermal states of the surrounding rock at the early and long-term operational stages of the TES caverns, respectively. However, as the separation distance decreased, the rock between the caverns reached thermal steady-state more quickly, and thus the heat loss from the caverns tended to converge rapidly to the value of heat loss occurred under thermal steady-state conditions in the surrounding rock. This result implies that the operating cost of heating the surrounding rock (i.e., rock heating) can be reduced with a reduction in the separation distance between multiple caverns, and suggests that the separation distance should be determined by considering the operating cost of rock heating as well as the construction cost of the caverns.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.1-9
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• 2006

Geological storage of captured $CO_2$ is a new way of reducing greenhouse gas emissions to protect the climate, but is based on the established technology associated with injection of fluids underground. The geological formations of interest for this technique include operational and depleted oil and gas fields, and deep saline aquifers. Prediction of storage performance will depend on models of the behaviour of $CO_2$ in geological formations; these need to be refined and verified, and methods of monitoring developed and proved. These needs can be met through monitored demonstration and research projects. Current commercial projects that are demonstrating $CO_2$ storage include Sleipner, Weyburn, ORC, and In Salah; research projects include West Pearl Queen, Nagaoka, and Frio. In this paper, some of the monitored injection projects are described. The reservoirs employed for storing $CO_2$, and the associated monitoring techniques, are briefly reviewed. It is argued that small-scale research projects, used to develop techniques and prove models, are complementary to the large-scale monitored injections that will establish the viability of this technique for mitigating climate change.