• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3849-3854
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• 2022

The present work aims to optimize the radiation protection efficiency for ion-selective containers used in the liquid treatment for the nuclear power plant (NPP) cooling cycle. Some naturally occurring rocks were examined as filler materials to reduce absorbed dose and equivalent dos received from the radioactive waste container. Thus, the absorbed dose and equivalent dose were simulated at a distance of 1 m from the surface of the radioactive waste container using the Monte Carlo simulation. Both absorbed dose and equivalent dose rate are reduced by raising the filler thickness. The total absorbed dose is reduced from 7.66E-20 to 1.03E-20 Gy, and the equivalent dose is rate reduced from 183.81 to 24.63 µSv/h, raising the filler thickness between 0 and 17 cm, respectively. Also, the filler type significantly affects the equivalent dose rate, where the redorded equivalent dose rates are 24.63, 24.08, 27.63, 33.80, and 36.08 µSv/h for natural rocks basalt-1, basalt-2, basalt-sill, limestone, and rhyolite, respectively. The mentioned results show that the natural rocks, especially a thicker thickness (i.e., 17 cm thickness) of natural rocks basalt-1 and basalt-2, significantly reduce the gamma emissions from the radioactive wastes inside the modified container. Moreover, using an outer cementation concrete wall of 15 cm causes an additional decrease in the equivalent dose rate received from the container where the equivalent dose rate dropped to 6.63 µSv/h.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.337-349
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• 1992

The Tertiary basins in Korea have widely been studied by numerous researchers producing individual results in sedimentology, paleontology, stratigraphy, volcanic petrology and structural geology, but interdisciplinary studies, inter-basin analysis and basin-forming process have not been carried out yet. Major work of this study is to elucidate evidences obtained from different parts of a basin as well as different Tertiary basins (Pohang, Changgi, Eoil, Haseo and Ulsan basins) in order to build up the correlation between the basins, and an overall picture of the basin architecture and evolution in Korea. According to the paleontologic evidences the geologic age of the Pohang marine basin is dated to be late Lower Miocence to Middle Miocene, whereas other non-marine basins are older as being either Early Miocene or Oligocene(Lee, 1975, 1978: Bong, 1984: Chun, 1982: Choi et al., 1984: Yun et al., 1990: Yoon, 1982). However, detailed ages of the Tertiary sediments, and their correlations in a basin and between basins are still controversial, since the basins are separated from each other, sedimentary sequence is disturbed and intruded by voncanic rocks, and non-marine sediments are not fossiliferous to be correlated. Therefore, in this work radiometric, magnetostratigraphic, and biostratigraphic data was integrated for the refinement of chronostratigraphy and synopsis of stratigraphy of Tertiary basins of Korea. A total of 21 samples including 10 basaltic, 2 porphyritic, and 9 andesitic rocks from 4 basins were collected for the K-Ar dating of whole rock method. The obtained age can be grouped as follows: $14.8{\pm}0.4{\sim}15.2{\pm}0.4Ma$, $19.9{\pm}0.5{\sim}22.1{\pm}0.7Ma$, $18.0{\pm}1.1{\sim}20.4+0.5Ma$, and $14.6{\pm}0.7{\sim}21.1{\pm}0.5Ma$. Stratigraphically they mostly fall into the range of Lower Miocene to Mid Miocene. The oldest volcanic rock recorded is a basalt (911213-6) with the age of $22.05{\pm}0.67Ma$ near Sangjeong-ri in the Changgi (or Janggi) basin and presumed to be formed in the Early Miocene, when Changgi Conglomerate began to deposit. The youngest one (911214-9) is a basalt of $14.64{\pm}0.66Ma$ in the Haseo basin. This means the intrusive and extrusive rocks are not a product of sudden voncanic activity of short duration as previously accepted but of successive processes lasting relatively long period of 8 or 9 Ma. The radiometric age of the volcanic rocks is not randomly distributed but varies systematically with basins and localities. It becomes generlly younger to the south, namely from the Changgi basin to the Haseo basin. The rocks in the Changgi basin are dated to be from $19.92{\pm}0.47$ to $22.05{\pm}0.67Ma$. With exception of only one locality in the Geumgwangdong they all formed before 20 Ma B.P. The Eoil basalt by Tateiwa in the Eoil basin are dated to be from $20.44{\pm}0.47$ to $18.35{\pm}0.62Ma$ and they are younger than those in the Changgi basin by 2~4 Ma. Specifically, basaltic rocks in the sedimentary and voncanic sequences of the Eoil basin can be well compared to the sequence of associated sedimentary rocks. Generally they become younger to the stratigraphically upper part. Among the basin, the Haseo basin is characterized by the youngest volcanic rocks. The basalt (911214-7) which crops out in Jeongja-ri, Gangdong-myon, Ulsan-gun is $16.22{\pm}0.75Ma$ and the other one (911214-9) in coastal area, Jujon-dong, Ulsan is $14.64{\pm}0.66Ma$ old. The radiometric data are positively collaborated with the results of paleomagnetic study, pull-apart basin model and East Sea spreading theory. Especially, the successively changing age of Eoil basalts are in accordance with successively changing degree of rotation. In detail, following results are discussed. Firstly, the porphyritic rocks previously known as Cretaceous basement (911213-2, 911214-1) show the age of $43.73{\pm}1.05$ 및 $49.58{\pm}1.13Ma$(Eocene) confirms the results of Jin et al. (1988). This means sequential volcanic activity from Cretaceous up to Lower Tertiary. Secondly, intrusive andesitic rocks in the Pohang basin, which are dated to be $21.8{\pm}2.8Ma$ (Jin et al., 1988) are found out to be 15 Ma old in coincindence with the age of host strata of 16.5 Ma. Thirdly, The Quaternary basalt (911213-5 and 911213-6) of Tateiwa(1924) is not homogeneous regarding formation age and petrological characteristics. The basalt in the Changgi basin show the age of $19.92{\pm}0.47$ and $22.05{\pm}0.67$ (Miocene). The basalt (911213-8) in Sangjond-ri, which intruded Nultaeri Trachytic Tuff is dated to be $20.55{\pm}0.50Ma$, which means Changgi Group is older than this age. The Yeonil Basalt, which Tateiwa described as Quaternary one shows different age ranging from Lower Miocene to Upper Miocene(cf. Jin et al., 1988: sample no. 93-33: $10.20{\pm}0.30Ma$). Therefore, the Yeonil Quarterary basalt should be revised and divided into different geologic epochs. Fourthly, Yeonil basalt of Tateiwa (1926) in the Eoil basin is correlated to the Yeonil basalt in the Changgi basin. Yoon (1989) intergrated both basalts as Eoil basaltic andesitic volcanic rocks or Eoil basalt (Yoon et al., 1991), and placed uppermost unit of the Changgi Group. As mentioned above the so-called Quarternary basalt in the Eoil basin are not extruded or intruaed simultaneously, but differentiatedly (14 Ma~25 Ma) so that they can not be classified as one unit. Fifthly, the Yongdong-ri formation of the Pomgogri Group is intruded by the Eoil basalt (911214-3) of 18.35~0.62 Ma age. Therefore, the deposition of the Pomgogri Group is completed before this age. Referring petrological characteristics, occurences, paleomagnetic data, and relationship to other Eoil basalts, it is most provable that this basalt is younger than two others. That means the Pomgogri Group is underlain by the Changgi Group. Sixthly, mineral composition of the basalts and andesitic rocks from the 4 basins show different ground mass and phenocryst. In volcanic rocks in the Pohang basin, phenocrysts are pyroxene and a small amount of biotite. Those of the Changgi basin is predominant by Labradorite, in the Eoil by bytownite-anorthite and a small amount pyroxene.

• The Journal of the Petrological Society of Korea
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• v.27 no.4
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• pp.185-194
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• 2018

The basaltic rocks of Daljeon-ri columnar joint (Natural Monuments # 415) and Noeseongsan Noerok site (Natural Monuments # 547) were analysed in order to understand basalt types of two areas. The basaltic rocks of the Pohang Daljeon-ri columnar joint show a typical porphyritic texture containing phenocrysts (olivine and clinopyroxene) and groundmasses composed of clinopyroxene, plagioclase, and opaque minerals,. In contrast, basaltic rocks of Noeseongsan Noerok are characterized by fine-grained groundmass with large phenocrysts of plagioclase. Other analysis such as magnetic susceptibility, X-ray diffraction and X-ray fluorescence also support the petrological differences of two basalt rocks. The Daljeon-ri basaltic rocks are plotted on phonotephrite volcanic rocks of alkaline series in TAS(total alkali silica), and on within plate basalt in Zr-Ti diagram. The Noeseongsan basalts, on the other hand, are plotted on basaltic andesite to andesite of sub-alkaline series in TAS, and on volcanic arc basalt in Zr-Ti diagram. These results indicate that the original mantle materials between two basalt rocks were different each other, which probably originated from the change of a tectonic setting in the southeastern Korean peninsula during the Miocene.

• Economic and Environmental Geology
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• v.17 no.3
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• pp.215-230
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• 1984

Petrological, paleomagnetic, geomorphological and structural studies on the southern part of, so called, Chugaryeong rift valley, have been carried out in order to clarify the nature of the rift valley. Three stages of volcanic activities characterized by Jijangbong acidic volcanic rocks and tholeiitic and andesitic basalt of Cretaceous age(?), and Jongok Quaternary olivine basalt occurred along the Dongducheon fault line. Jijangbong acidic volcanic rocks distributed in the central part of the studied area consist of rhyodacite, acidic tuff and tuff breccia, which are bounded by Dongsong fault on the east and Daegwangri fault on the west. The Jongok basalt differs from those of Ulrung and Jeju islands in mineralogy, chemical composition and differentiation. Jongok basalt distributed along the Hantan river dilineates the vesicles curved toward downstream direction and increment of numbers and thickness of lava flow toward upstream direction. These facts suggest that lava flowed from upstream side of the river. Rectangular drainage patterns also support the presence of the Dongducheon, Pocheon, Wangsukcheon and Kyonggang faults which were previously known. LANDSAT image, however, does not show any lineaments which could be counted as a graben or rift valley. Displacement of Precambrian quartzite and Jurassic Daedong supergroup along the southwestern extension of the Dongducheon fault shows the right lateral movement. The Paleomagnetic study of the tholeiitic and andesitic basalts from Baegeuri, Jangtanri and Tonghyeonri located at 2. 3km east, 0km east, and 1.5km west of Dongducheon fault respectively shows that their VGP(Virtual Geomagnetic Pole) being to intermediate geomagnetic field of short duration which suggests that they formed in almost same period. Mean VGP of Jongok basalt is located 82.4N and 80.6E. This is in good coincidence with worldwide VGP of Plio-Pleistocene indicating that Jongok basalt was extruded during Plio-Pleistocene epoch, and suggesting that the studied area has been tectonically stable since then. From the present study, the tectonic episode of the region is concluded as following three stages. 1. The 1st period is worked by the Daebo orogeny of Jurassic during which granodiorite was intruded in Precambrian basement. 2. The 2nd period is the time when right lateral strike-slip fault of NNE-SSW direction was formed probably during late Cretaceous to Paleogene and the Jijangbong acidic volcanic rocks and the older basalts were extruded. 3. The 3rd period is the time when the fault was rejuvenated during Pliocene or Pleistocene accompanied by the eruption of Jongok basalt. As a conclusion, geologic structure of the studied area is rather fault line valley than graben or rift valley, which is formed by differential erosion along the Dongducheon fault suggesting a continuation of the Sikhote-Alin fault. The volcanic rocks including the Jijangbong acidic rocks, tholeiitic-andesitic basalt and olivine basalt are associated with this fault line.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1835-1841
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• 2019

The mass attenuation coefficient ${\mu}_m$ for eight rock samples having different chemical composition was simulated using the MCNP 5 code in energy range($0.002MeV{\leq}E{\leq}10MeV$). Moreover, the ${\mu}_m$ for the studied rock samples was computed theoretically using XCOM database. The comparison between simulated and computed data for all selected rock samples showed a good agreement with differences varied between 0.01 and 8%. The highest ${\mu}_m$ was found for basalt rocks M2 and M1 and the lowest one is reported for limestone rocks Dike. The simulated values of the ${\mu}_m$ then were used to calculate other important shielding parameters such as the mean free path, effective electron density and effective atomic number. The exposure buildup factor EBF was also computed for the selected rocks with the contribution of G-P fitting parameters and the highest EBF attended by the basalt sample Sill and varied between 1.022 and 744 in the energy range between ($0.015MeV{\leq}E{\leq}15MeV$) but the lowest EBF achieved by basalt sample M2 and varied between 1.017 and 491 in the same energy range.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.127-133
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• 2003

The effect of parent rocks to the soil microbial diversity were investigated in soils developed from granite, limestone and basalt parent rocks. In the soils, microbial populations were positively related to the soil chemicals, such as soil pH with ftuorescent Pseudomonas, and soil EC with actinomycetes, fungi, mesophilic Bacillus and alkaliphilic bacteria. Gram negative bacteria, spore forming Bacillus, were maintained relatively same levels of population between granite, limestone and basalt soils. Among the species of Burkholderia, Pseudomonas and Ralstonia were dominated in the granite soils, Pseudomonas, Burkholderia and Phyllobacterium in the limestone soils, and Burkholderia in the basalt soils.

• Asian Journal of Turfgrass Science
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• v.9 no.1
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• pp.81-89
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• 1995

The variations of the soil texture, $SiO_2$ /$Al_2$$O_3$ ratio, buffer action, exchangeable base, ex-changeable hydrogen, and mineral nutrients were investigated to estimate the grade of the soil fertility of the soil derived from the different parent rocks such as the granite in Kwangnung and the basalt in Chejudo. The results investigated were showed as follows : Basalt soils in Chejudo belong to sandy clay, light clay and sandy clay loam, while gramite soils in Kwangnung sandy loam. The $SiO_2$ /$AI_2$$O_3$ ratio of the grassland in Chejudo was 1.11 and that of the oak forest soils was 1.24, while granite soils in Kwangnung 1.54 and 1.46, respectively. The buffer actions of ba-salt soils against the N /10 HCI and $Ca(OH)_2$ were stronger than those of granite soils. The $SiO_2$/$Al_2$$O_3$ + $Fe_2$$O_3$ ratios of grassland and oak forest soils of basalt in Chejudo showed 1.10 and 1.24 respectively, while those of the grassland and oak forest of Kwangnung 1.44 and 1.33. The base exchange capacity of basalt soils which has higher value of exchangeable hydrogen was stronger than that of granite soils. But the base saturation of granite soils showed higher value than that of basalt soils. Water contents of basalt soils in Chejudo was lower than that of granite soils fo Kwangnung Basalt soils in Chejudo contain still more humus and total nitrogen than gran-ite soils in kwangnung, The amount of available nitrogen, available phosphorus and exchangeable calcium of granite soils were more than that of basalt soils, Therefore, estimating the soil fertility, granite soils in Kwangnung is higher than that of basalt soils in Chejudo.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.1
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• pp.1-7
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• 2011

Basalt originates from volcanic magma and flood volcanoes, a very hot fluid or semifluid material under the earth's crust, solidified in the open air. Basalt is a common term used for a variety of volcanic rocks, which are gray, dark in colour, formed from the molten lava after solidification. Recently, attention has been devoted to continuous basalt fibers (CBF) whose primary advantage consists in their low cost, good resistance to acids and solvents, and good thermal stability. In order to investigate reinforcement effect, this paper did FEM analysis with shell element. The result were as follows; BCF deck plate did elastic behavior to 450 kN, reinforcement effect of basalt fiber (BF) was less. But BCF's perpendicular deflection occurred little about 23 mm comparing with RC deck plate in load 627 kN. Stiffness was very improved by basalt fiber reinforcement.

• The Journal of the Petrological Society of Korea
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• v.16 no.2 s.48
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• pp.73-81
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• 2007

A basaltic tuff formation (Upper Basaltic Tuff of the Janggi Group) occurs in close association with basalt (Yeonil Basalt) at the Tertiary Janggi basin. The purpose of this paper is to describe the occurrence of the basaltic tuff and associated basalt and to determine their mode of formation. The basaltic rocks of the study area show few distinct lithofacies, all of which are originated from the interaction of basaltic magma with external water. The four lithofacies include (1) sideromelane shard hyaloclastite, (2) pillow breccia, (3) entablature-jointed basalt, and (4) in-situ breccia. The sideromelane shard hyaloclastite constitutes most of the Upper Basaltic Tuff and has a gradual contact with the pillow breccia. The pillow breccia consists of a poorly sorted mixture of isolated and broken pillows, and small basalt globules and fragments engulfed in a volcanic matrix of sideromelane shard hyaloclastite. The entablature-jointed basalt occurs as a small body within the hyaloclastite. It is characterized by irregularly-curved joints known as entablature. The in-situ breccia occurs as a marginal facies of entablature-jointed basalt, and its width varies from 10 to 30m. The result of this study indicates that the basaltic tuff and associated basalts of the study area were produced by the volcanic activity of same period and the basaltic tuff was formed by subaqueous eruption of basaltic lava followed by nonexplosive quench fragmentation.

• Journal of the Korean earth science society
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• v.34 no.3
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• pp.274-285
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• 2013

The purpose of this study was to develop geological field study sites for learning topography and geology of the area with igneous rocks, specifically in Duibaejae volcanic edifice and Seonang-bawi that were distributed in Goseong-gun, Gangwon-do area. As a follow up, we conducted a study to examine the effect of the study sites when applied to high school freshmen Earth science course. The study proceeded based on the Orion's model in the order of preparatory unit, field trip, and summary unit. The geological field study sites were developed based on the geological study elements presented in the Korean Earth science curriculum. Before the field trip, students simply memorized factual knowledge on minerals, rocks and etc., and showed very low level of understanding on the formation process of the region that was distributed with granite and basalt. Especially, their understanding showed that granite and basalt were formed from the same magma at the same time. After the field trip, they increased in-depth level of understanding about minerals, rocks, and geological structures, but were not able to explain the topographical characteristics of the two rocks because they did not recognize the times of the creation of granite and basalt. The reason is that they have learned the simple concept of the process of forming granite and basalt in their middle school, but that they have not learned the meaning of the difference between two the geological eras when each of the two rocks, granite and basalt, were formed.