• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.179-188
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• 2016

Spent fuels from nuclear power plants, as well as high-level radioactive waste from the recycling of spent fuels, should be safely isolated from human environment for an extremely long time. Recently, meaningful studies on the development of deep borehole radioactive waste disposal system in 3-5 km depth have been carried out in USA and some countries in Europe, due to great advance in deep borehole drilling technology. In this paper, domestic deep geoenvironmental characteristics are preliminarily investigated to analyze the applicability of deep borehole disposal technology in Korea. To do this, state-of-the art technologies in USA and some countries in Europe are reviewed, and geological and geothermal data from the deep boreholes for geothermal usage are analyzed. Based on the results on the crystalline rock depth, the geothermal gradient and the spent fuel types generated in Korea, a preliminary deep borehole concept including disposal canister and sealing system, is suggested.

• Conservation Science in Museum
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• v.19
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• pp.1-18
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• 2018

The Stele for National Preceptor Hongbeop from the Jeongtosa Temple site in Chungju is one of the most important stone cultural heritage items for exemplifying the style of the Goryeo era. Despite its obvious value, this relic has been stored in a weathered condition at the National Museum of Korea. It had suffered various dismantling and displacements during the Japanese colonial period and had long been exposed in the open air. The stele was selected as a subject for the Stone Monuments Restoration Project launched by the National Museum of Korea in 2015. In preparation for its outdoor exhibition as part of the restoration project, this study investigated the characteristics of its materials, produced a map of its deterioration from weathering, and carried out ultrasonic analysis of the materials to provide findings useful for conservation treatment. The materials analysis revealed that the turtle-shaped pedestal of the stele was made from two-mica granite consisting of medium-grained quartz, plagioclase, alkali feldspar, biotite, and muscovite. Its body stone is crystalline marble, the rock-forming mineral in which is medium-grained calcite in a rose-pink color with dark grey spots. The dragon top of the stele is made of crystalline marble, the major component of which is medium-grained calcite of a light-grey color. The deterioration consists of 21.5% abrasion on the stone body, with its south face most damaged, and 18.6% granular disintegration, with the north face most damaged. The ultrasonic material characterization conducted for mapping the general condition of weathering shows low values on the parts-assembly area of the turtle-shaped pedestal and on the upper portion of the stone body. It is considered that there is dislocation due to partial blistering and fracturing as well as to the differences in surface treatment. Prior to the outdoor exhibition of the stele, the surface was cleaned of contaminants and was consolidated based on the scientific investigation in order to prevent weathering from the external environment.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.21-36
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• 2005

Although the main geology of Korea consists of granite and gneiss, it Is not uncommon to encounter anisotropy Phenomena in crosshole radar tomography even when the basement is crystalline rock. To solve the anisotropy Problem, we have developed and continuously upgraded an anisotropic inversion algorithm assuming a heterogeneous elliptic anisotropy to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. In this paper, we discuss the developed algorithm and introduce some case histories on the application of anisotropic radar tomography in Korea. The first two case histories were conducted for the construction of infrastructure, and their main objective was to locate cavities in limestone. The last two were performed In a granite and gneiss area. The anisotropy in the granite area was caused by fine fissures aligned in the same direction, while that in the gneiss and limestone area by the alignment of the constituent minerals. Through these case histories we showed that the anisotropic characteristic itself gives us additional important information for understanding the internal status of basement rock. In particular, the anisotropy ratio defined by the normalized difference between maximum and minimum velocities as well as the direction of maximum velocity are helpful to interpret the borehole radar tomogram.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.505-517
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• 1997

Lead and zinc mineralization of the Kwangsin mine was formed in quartz and carbonate veins that filled fault-related fractures in the limestone-rich Samtaesan Formation of the Chosun Supergroup and the phyllite-rich Suchangni Formation of unknown age. A K-Ar date of alteration sericite indicates that the Pb-Zn mineralization took place during Late Cretaceous (83.5 Ma), genetically in relation to the cooling of the nearby Muamsa Granite (83~87 Ma). Mineral paragenesis can be divided into three stages (I, II, III): (I) the deposition of barren massive white quartz, (II) the main Pb-Zn mineralization with deposition of white crystalline quartz and/or carbonates (rhodochrosite and dolomite), and (III) the deposition of post-ore barren calcite. Mineralogic and fluid inclusion data indicate that lead-zinc minerals in middle stage II (IIb) were deposited at temperatures between $182^{\circ}$ and $276^{\circ}C$ from fluids with salinities of 2.7 to 5.4 wt. % equiv. NaCl and with log $fs_2$ values of -15.5 to -11.8 atm. The relationship between homogenization temperature and salinity data indicates that lead-zinc deposition was a result of fluid boiling and later meteoric water mixing. Ore mineralization occurred at depths of about 600 to 700 m. Sulfur isotope compositions of sulfide minerals (${\delta}^{34}S_{CDT}=9.0{\sim}14.5$ ‰) indicate a relatively high ${\delta}^{34}S_{{\Sigma}S}$ value of ore fluids (up to 14 ‰), likely indicating an igneous source of sulfur largely mixed with an isotopically heavier sulfur source (possibly sulfates in surrounding sedimentary rocks). There is a remarkable decrease of calculated ${\delta}^{18}O$ value of water in hydrothermal fluids with increasing paragenetic time: stage I, 14.6~10.1 ‰; stage IIa, 5.8~2.2 ‰; stage IIb, 0.8~2.0 ‰; stage IIc, -6.1~-6.8 ‰, This indicates a progressive increase of meteoric water influx in the hydrothermal system at Kwangsin. Measured and calculated hydrogen and oxygen isotope values indicate that the Kwangsin hydrothermal fluids was formed from a circulating (due to intrusion of the Muamsa Granite) meteoric waters which evolved through interaction mainly with the Samtaesan Formation (${\delta}^{18}O=20.1$ to 24.9 ‰) under low water/rock ratios.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.75-81
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• 1973

The morphological, physical, and chemical properties of Sonjeong series derived from acidic crystalline rocks are presented. Also it deals with the genesis and classification of the Songjeong series. Morphologically these soils have brown to dark brown loam A horizons and yellowish red to red clay loam Bt horizons with moderate, medium subangular blocky structure and thin patchy clay cutans on the ped faces. C horizons are very deep, yellowish red to yellowish brown fine sandy loam or sandy loam with original rock structure. Physically distribution of particle size indicates that clay increases with depth up to argillic horizons but below the argillic horizons clay content decrease. The moisture holding capacity is fairly good in Songjeong soils. Chemically soil reaction is strongly to very strongly acid throughout the profile and content of organic matter is less than 1 per cent except A horizons. Cation exchange capacity ranges from 5 to 9 me/100g of soils and base saturation is less than 35 per cent throughout the profile. The natural fertility of Songjeong soils are usually low. It needs lime, organic matter, and heavy application of fertilizer for the crop land. These soils occur temperate and humid climate under coniferous, deciduous, and mixed forest vegetation. Songjeong soils are classified as Red-Yellow Soils. Characteristically Songjeong soils are similar to Red-Yellow Podzolic soils in the United States but lack of A2 horizons and are quite liket Red-Yellow Soils of the Japan. According to new classification system which is 7th approximation of USDA Songjeong soils can be classified as fine loamy, mesic family of Typic Hapludults and in the FAO/UNESCO project World Soil Map as Orthic Acrisols.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.101-109
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• 2022

The mobility and transport of radioactive cesium are crucial factors to consider for the safety assessment of high-level radioactive waste disposal sites in granite. The retardation of radionuclides in the fractured crystalline rock is mainly controlled by the hydrochemical condition of groundwater and surface reactions with minerals present in the fractures. This paper reports the experimental results of cesium sorption to the Wonju Granite, a typical Mesozoic granite in Korea, performed in an anaerobic chamber that mimics the anoxic environment of a deep disposal site. We measured the rates and amounts of cesium (¹³³Cs) removed by crushed granite samples in different electrolyte (NaCl, KCl, and CaCl₂) solutions and a synthetic groundwater solution, with variations in the initial cesium concentration (10^-5, 5×10^-6, 10^-6, 5×10^-7 M). The cesium sorption kinetic and isotherm data were successfully simulated by the pseudo-second-order kinetic model (r²= 0.99) and the Freundlich isotherm model (r²= 0.99), respectively. The sorption distribution coefficient of granite increased almost linearly with increasing biotite content in granite samples, indicating that biotite is an effective cesium scavenger. The cesium removal was minimal in KCl solution compared to that in NaCl or CaCl₂ solution, regardless of the ionic strength and initial cesium concentration that we examined, showing that K⁺ is the most competitive ion against cesium in sorption to granite. Because it is the main source mineral of K⁺ in fracture fluids, biotite may also hinder the sorption of cesium, which warrants further research.

• Journal of the Korean earth science society
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• v.21 no.4
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• pp.437-448
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• 2000

The Middle Carboniferous Gabsan Formation is distributed in the Cheongrim area of southern Yeongwol and the Mt. Gachang area of Chungbuk Province. This study was carried out to investigate the lithological characters and geochemical composition of the limestones and to find out controlling structures of the limestones of the formation. The limestones of the Gabsan Formation are characterized by the light gray to light brown in color and fine and dense textures. The limestone grains are composed of crinoid fragments, small foraminfers, fusulinids, gastropods, ostracods, etc. Due to the recrystallization, some limestones consist of fine crystalline calcites. The chemical analysis of limestones of the formation was conducted to find out the contents of CaO, MgO, Al$_2$O$_3$, Fe$_2$O$_3$ and SiO$_2$. The content of CaO ranges from 49.78-60.63% and the content of MgO ranges from 0.74 to 4.63% The contents of Al$_2$O$_3$ and Fe$_2$O$_3$ are 0.02-0.55% and 0.02${\sim}$0.84% , respectively. The content of SiO$_2$ varies from 1.55 to 4.80%, but some samples contain more than 6.0%. The limestones of the formation can be grouped into two according to the CaO content: One is a group of which CaO content ranges from 49.78 to 56.26% and the other is a group of which CaO content varies from 59.36 to 60.38%. In the first group, the contents of Al$_2$O$_3$, Fe$_2$O$_3$ and SiO$_2$ range very irregularly according to the CaO content. In the second group, the values of MgO, Al$_2$O$_3$, Fe$_2$O$_3$ and SiO$_2$ are nearly same. Detailed structural analysis of mesoscopic structures and microstructures indicates the five phase of deformation in the study area. The first phase of deformation(D$_1$) is characterized by regional scale isoclinal folds, and bedding parallel S$_1$ axial plane foliation which is locally developed in the mudstone and sandstone. Based on the observations of microstructures, S$_1$ foliations appear to be developed by grain preferred orientation accompanying pressure-solution. During second phase of deformation, outcrop scale E-W trending folds with associated foliations and lineations are developed. Microstructural observations indicate that crenulation foliations were formed by pressure-solution, grain boundary sliding and grain rotation. NNW and SSE trending outcrop scale folds, axial plane foliations, crenulation foliations, crenulation lineations, intersection lineations are developed during the third phase of deformation. On the microscale F$_3$ fold, axial plane foliations which are formed by pressure solution are well developed. Fourth phase of deformation is characterized by map scale NNW trending folds. The pre-existing planar and linear structures are reoriented by F$_4$ folds. Fifth phase of deformation developed joints and faults. The distribution pattern of the limestones is mostly controlled by F$_1$ and F$_4$ folds.