화강암지역에 고준위 원자력 폐기물 처리에 대한 안정성 평가

오창환,Oh, Chang Whan 대한자원환경지질학회 1996 자원환경지질 Vol.29 No.2

All the radionuclides in high-level nuclear waste will decay to harmless levels eventually but for some radionuclides decay is so slow that their radiation remains dangerous for times on the order of tens or hundreds of thousands of years. At the present time, the most favorite disposal plan for high-level radioactive waste is a mined geological disposal in which canister enclosing stable solid form of radioactive waste is placed in mined cavities locating hundred meters below the surface. The chief hazard in such disposal is dissolution of radionuclides from the waste in the groundwater that will eventually carry the dissolved radionuclides to surface environments. The hazard from possible escape of the radionuclides through groundwater can be delayed by engineered and geologic barriers. The engineered barriers can become useless by unexpected geologic catastrophe such as volcanism, earthquake, and tectonic movement and by fraudulent work such as careless construction, improperly welded canisters within the first few decades or centuries. As a result, dangerously radioactive waste which is still intensively radioactive is directly exposed to attack by moving groundwater. All the more, it is almost impossible to control repositories for times more than 10,000 years. Therefore, naturally controlled geologic, barriers whose properties will not be changed within 10,000 years are important to guarantee the safety of repositories of high-level radioactive waste. In Sweden and France, the suitability of granite for the mined geological disposal of high-level waste has been studied intensively. According to the research in Sweden and France, granites has the following physio-chemical characteristics which can delay the transportation of radionuclide by groundwater. First, the permeabilities of granites decreases as the depth increases and is $10^{-8}{\sim}10^{-12}m/s$ at depth below 300 m. Second, groundwater at depth below 300 m has pH=7-9 and reducing condition (Eh=-0.1~0.4). This geochemical condition is desirable to prevent both canister and solid waste from corrosion. Third most radionuclides are not transported by low solubilities and some radionuclide with high solubility such as Cs and Sr are retarded by absorption of geologic media through which ground water flows. Therefore, if high-level waste is disposed at depth below 300 m in the granite body which has a low permeability and is geologically stable more than 10,000 years, the safety of repositories from the hazard due to radionuclide escape can guaranteed for more than 10,000 years.

선형계획에 있어서의 정책적 목표설정문제

오창환,Oh, Chang Whan 한국통계학회 1973 Journal of the Korean Statistical Society Vol.1 No.1

선형계획의 실제적문제에 있어서는 장기적인 전망을 반영시켜 그 계획에 어떤 자극을 주기 위하여 달성불가능한 정책적목표를 설정할 수도 있고 혹은 그 계획이 어떤 기준을 수행하고 있는가 또는 그러한 목표가 계획에 도입될 때 계획은 어떻게 변경될 것인가를 판단하기 위해서 달성가능한 정책적목표를 설정할 수가 있다. 이것을 해석기하학적으로 표현하면 "선형계획에 있어서 정책적목표는 일반적으로 실행가능집합 (convex set)의 어떤 단점으로부터의 $l_1$ metric($l_1$ 거리공간)으로 해석할 수가 있다.가 있다.

유체포유물의 생성시 온도-압력 조건과 유체포유물의 물리화학적 특성연구에 있어서의 컴퓨터 프로그램이용

오창환,최상훈,Oh, Chang-Whan,Choi, Sang-Hoon 대한자원환경지질학회 1993 자원환경지질 Vol.26 No.1

Fluid inclusion has been widely used to study the origin and physiochemical conditions of ore deposits. However, it is difficult to get the accurate physiochemical data from fluid inclusion study due to the error of microthermometric data and the complexity of calculation of density and isochore of fluid inclusion. The computer programs HALWAT, $CO_2$, and CHNACL written by Nicholls and Crowford (1985) partly contributed to improve the accuracy of physiochemical data by using complicated equations. These programs are applied to determine the densities and isochores of fluid inclusions for the Cretaceous Keumhak mine using Choi and So's data (1992) and for the Jurassic Samhwanghak mine using Yun's data (1990). The estimated PoT for Keumhak mine from calculated isochores of coexisting fluid inclusions are $230^{\circ}{\sim}290^{\circ}C$ and 500~800 bar which matche well to the poT estimated by Choi and So ($280^{\circ}{\sim}360^{\circ}C$ and 500~800 bar, 1992). However, the poT for Samwhanghak mine estimated in this study by combining the calculated isochores and sulfur isotope geothermometer data by Yun (1990) are about 4~7 kb at $329{\pm}50^{\circ}{\sim}344{\pm}55^{\circ}C$ which are quite different form the P-T estimates by Yun ($255^{\circ}{\sim}294^{\circ}C$ and 1.2~1.9kb, 1990). This discrepancy caused by misinterpretation of homogenization temperature (Th) of fluid inclusion and by application of inappropriate isochores. The application of homogenization temperature and/or inappropriately selected isochore to determine the trapping PoT condition of ore-deposits should be avoided, particularly for ore-deposits formed at pressures higher than 1~2 kb.

Geochemistry, zircon U-Pb ages and Lu-Hf isotopes of Triassic plutons in the eastern Gyeonggi Massif, Korean Peninsula: Magma genesis and geodynamic implications for East Asia

Oh Chang Whan(오창환),Kawaguchi Kenta(가와구찌 겐타),Jeong Ji Wan(정지완) 한국암석학회 2023 한국암석학회 학술발표회 논문집 Vol.2023 No.6

청주-미원지역 중부 옥천변성대의 변성진화과정

오창환(Chang Whan Oh),권용완(Yong Wan Kwon),김성원(Sung Won Kim) 한국암석학회 1999 암석학회지 Vol.8 No.2

문경지역에 분포하는 변성 염기성암과 변성 퇴적암에 대한 백악기 화강암의 열변성작용

오창환(Chang Whan Oh),김성원(Soung Weon Kim),김종섭(Jong Seab Kim) 한국암석학회 1993 암석학회지 Vol.2 No.2

금융적 측면에서 본 전남제조기업의 문제점

오창환(Chang Whan Oh) 한국경영학회 1971 經營學硏究 Vol.1 No.-

This paper is intended to analyze factors contributing to the underdevelopment of the Chonnam Province manufacturing industries with particular emphasis on the financial aspect. The per capita income in the Chonnam Province was the lowest (only 44.7% of that of Seoul) in Korea in 1966. It resulted from the underdevelopment of manufacturing industries in the Chonnam Province. Taking the case of Chonnam as a typical example of the local manufacturing industries, an analysis of its production aspect proves that 99% of it consists of the small-medium establishments, with such accompanying characteristics as lower level of productivity, wage rate, capital formation, profit rate and investment rate than the average value in Korea. Such characteristics result ultimately from the scarcity of the tangible fixed assets. (Those in Chonnam amount only to 5. 65% of those in Korea in 1969.) Though it is necessary to increase substantially the advance credit in order to overcome such a situation, the amount of loan to Chonnam shows a decreasing tendency relative to the entire nation (the ratio in 1970 is only 4%). This results in raising the level of dependence upon the private loan of higher interest rate and therefore increasing the interest burden in the manufacturing enterprises. The criterion for the selection of investment as the distribution criterion of fund is determined by the Rasmussen method on I. O. analysis. To absorb the surplus labor, to make efficient use of the scarce capital and to improve the industrial structure, the labor intensive business in the heavy industrial sector must be the object of the selective development policy, but the authorities have misled the direction of that policy. $quot;S$quot; company-a large scale firm-in Kwang-ju was put to microanalysis as the representative company in the Chonnam Province. The most efficient production program is planned by Linear Programming, making use of imported raw materials in $quot;S$quot; company. The rationalization of production or modernization of management enables $quot;S$quot; company to increase profit-the latent force of capital formation. The efficient use of restricted and scarce fund is attained by the efficient production program and the rational demand-supply program of raw material. Because of insufficient fund, the rationalization of producation is nut yet realized. Therefore, the profit rate and the capital formation rate are net only very low but also liabilities and net worth. Thus $quot;S$quot; company shows in substance the same qualities as the small-medium business enterprise. The central concern of Korean economy in 1970`s must focus all the efforts an the qualitative growth of local enterprises by making efficient use of the scarce fund.

용출액의 pH 변화가 토양내 중금속 용출에 미치는 영향과 그에 따른 국내 토양 오염 공정시험방법의 문제점

오창환(Chang Whan Oh),유연희(Youn Hee Yu),이평구(Pyeong Koo Lee),이영엽(Young Up Lee) 대한자원환경지질학회 2003 자원환경지질 Vol.36 No.3

전주시 하천 퇴적물시료, 호남고속도로 주변의 토양과 퇴적물 시료, 광산주변 광미 및 토양시료를 대상으로 토양오염 공정시험방법상의 용출법, 0.1N 유지용출법, Tessier et at.(1979)의 연속추출방법을 적용하여 중금속을 추출하고 그 결과를 비교하였다. 공정시험방법상의 용출법 사용시 산에 대한 완충능력이 있는 시료는 용출액의 pH 1(0.1N HCl)이 유지되지 못했고 용출액의 pH가 최고 8.0까지 증가하였다. 또한, 토양오염 공정시험방법상의 용출법 사용시 중금속 추출량(HPE)/0.1N 유지용출법 사용시 중금속 추출량(HPEM) 값의 평균치와 범위는 Cd의 경우 0.479와 0.145-0.929, Zn의 경우 0.534와 0.078-0.928, Mn의 경우 0.432와 0.041-0.992, Cu의 경우 0.359와 0.011-0.874, Cr의 경우 0.150과 0.018-0.530, Pb의 경우 0.219와 0.003-0.853 그록 Fe의 경우 0.088과 1.73×10-5-0.303이다. 이는 두 전처리 방법에 의해 추출된 중금속량의 차이가 Fe>Cr>Pb>Cu>Mn>Cd>Zn 순임을 지시한다. HPE, HPEM과 연속추출법 비교시 Zn, Cd, Mn의 경우 추출량은 대체적으로 연속추출 3단계까지의 합≥0.1N 유지용출법>연속추출 2단계까지의 합≥용출법 순이었으며, Cr과 Fe의 경우 연속추출 3단계까지 합>>0.1N 유지용출법>용출법 순이었으며 연속추출 2단계 까지 합은 Cr의 경우 0.1N 유지용출법의 추출량보다 낮았고 용출법의 추출량보다 높았다. Cu의 경우 연속추출 4단계까지의 합≥0.1N 유지용출법>3단계까지의 합=용출법으로 나타났다. 0.1N 유지위해 첨가된 염산의 양이 증가할수록, 즉 시료내의 산에 대한 완충능력이 증가할수록 HPE/HPEM 값이 감소하며, 완충능력이 큰 시료의 경우 모든 원소에서 HPE/HPEM이 0.2보다 낮다. 완충능력이 낮은 시료의 경우 Zn, Cd, Mn, Cu는 연속추출 1, 2단계의 합과 연속추출 3단계의 중금속 추출함량간의 차이가 적고, 다른 원소에 비해서 상대적인 유동도가 높기 때문에 HPe/HPEM이 대체적으로 0.2보다 높으며 0.6이상의 값을 갖는 시료가 많다. 그러나, Fe, Cr의 경우는 상대적으로 Zn, Cd, Mn, Cu에 비해 유동도가 낮고, 연속추출 3단계의 함량이 1+2단계의 한량과 차이가 커 완충능력이 낮은 시료의 HPE/HPEM 값도 전반적으로 0.2보다 낮다. 이러한 연구결과는 국내 토양오염 공정시험방법상의 전처리 방법인 용출법이 장래에 장기적으로 산성비와 같은 환경피해에 노출되어 토양의 완충능력이 감소하거나 상실될 수 있는 지역의 오염평가에 적합치 않을 가능성을 제시한다. Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam express-way, soils and tailings from mining area using three different methods (partial extraction in Standard Method, par-tial extraction method with maintaining 0.1 N of extraction solution and Sequential Extraction Method). In samples having buffer capacity against acid, pH 1 (0.1 N HCl) of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of HPE(heavy metals extracted using partial extraction in Standard Method)/HPEM(heavy metals extracted using partial extraction method with maintaining 0.1 N of extraction solution) values are 0.479 and 0.145_0.929 for Cd, 0.534 and 0.078_0.928 for Zn, 0.432 and 0.041_0.992 for Mn, 0.359 and 0.011_0.874 for Cu, 0.150 and 0.018_0.530 for Cr, 0.219 and 0.003_0.853 for Pb, and 0.088 and 1.73×10-5_0.303 for Fe. These data indicate that the difference between HPE and HPEM is large in the order of Fe, Cr, Pb, Cu, Mn, Cd and Zn. The amounts of heavy metals extracted decreases in the follow order; Sum III (sum of fraction I, II, III in sequential extrac-tion)>HPEM>Sum III (sum of fraction I and II)>HPE for Zn, Cd and Mn and Sum III>HPEM>HPE for Cr and Fe. In the case Cr, Sum II is lower than HPEM and higher than HPE. In case of Cu, extracted heavy metals is large in the order Sum IV>HPEM>Sum III@HPE. HPE/HPEM value decreases with increasing the amount of HCl used for maintaining 0.1 N of extraction solution. For samples with high buffer capacity, HPE/HPEM value in all elements is lower than 0.2. On the other hand, for samples with low buffer capacity, HPE/HPEM value are over 0.2 and many samples have values higher than 0.6 for Zn, Cd Mn and Cu due to the small difference between Sum II and Sum III, and relatively higher mobility. However, for Fe and Cr, HPE/HPEM value is below 0.2 even for samples with low buffer capacity due to their low mobility and big difference between Sum II and Sum III. This study indi-cates that the partial extraction method in Korean Standard Method of soil is not suitable for an assessment of soil contamination in area where buffer capacity of soil can be decreased or lost because of a long term exposure to environmental damage such as acidic rain.

Jurassic to Cretaceous magmatism in the Korean Peninsula, China, and Japan: Its implications for the Jurassic-Cretaceous tectonic evolution of the Northeast Asia

Chang Whan Oh(오창환),Seung Hwan Lee(이승환),Kenta Kawaguchi 한국암석학회 2024 한국암석학회 학술발표회 논문집 Vol.2024 No.5

무주 왕정리 일대 구상 화강편마암의 성인과 형성시기

오창환(Chang Whan Oh),이병춘(Byung Choon Lee),이기욱(Keewook Yi) 한국암석학회 2013 암석학회지 Vol.22 No.2

무주군 왕정리 지역에서 구상 화강편마암이 초기 원생대 변성퇴적암류를 관입하는 우백질 복운모 화강암내에 포획체의 형태로 나타난다. 우백질 복운모 화강암의 전암성분 분석치와 SHRIMP 저어콘 연대측정 결과는 우백질 복운모 화강암이 1875±75 Ma에 대륙 충돌 환경에서 형성된 S-type 화강암임을 지시한다. 우백질 복운모 화강암내에 나타나는 구상 화강편마암으로부터 추출된 모나자이트에 대한 SHRIMP 분석에 의해 구상 화강편마암을 형성시킨 변성작용 시기가 1867±4 Ma임이 밝혀졌고 이 변성 연령은 우백질 복운모 화강암의 관입시기와 오차 범위내에서 유사하다. 이는 우백질 복운모 화강암 관입시 마그마내로 침강한 변성퇴적암이 마그마에 의해 650-740oC, 4-6.5 kbar 정도의 열변성작용을 받아 구상 화강편마암이 만들어졌음을 지시한다. 열변성 작용시 근청석을 주로 하는 구상 화강편마암의 핵부가 만들어졌고 이때 일부 구상 화강편마암에서는 석영 및 장석을 포함한 일부 광물이 용융되어 만들어진 우백질 용융체가 핵부를 빠져나온 후 핵부 주변에서 결정화하여 우백질 각부를 형성하였다. 구상 화강편마암이 형성된 후 마그마 분화작용 중 최후에 남아있던 열수가 구상 화강편마암에 침투하여 후퇴 변성작용을 일으키고 이때 근청석이 pinite화 되면서 세립의 녹니석과 견운모로 치환되었다. 무주 화강편마암은 퇴적기원의 변성암이므로 앞으로는 무주 화강암질 편마암으로 명명하는 것이 적합하다. Orbicular granite gneisses occur as a xenolith within two-mica leucogranites, together with early Paleoproterozoic metasedimentary xenoliths, in Wangjeong-ri, Muju area. The whole-rock chemistries and SHRIMP zircon Pb/U ages of the leucogranites indicate that they are S-type granitoids formed in the continental tectonic setting at 1875±75 Ma. The SHRIMP age of monazites from the orbicular granite gneiss gives 1867±4 Ma as a metamorphic age which is similar to the intrusion age of the two-mica leucogranite within the error range. The similar ages between zircons and monazites represent that the orbicular granite gneisses formed by metamorphism during the intrusion of the two-mica leucogranite; the metasedimetary xenoliths which sank within the parent magma of leucogranites were metamorphosed into orbicular granite gneisses by thermal metamorphism (650-740oC, 4-6.5 kbar) due to the heat supplied from surrounding magma. During the thermal metamorphism, the core of orbicular granite gneiss mainly consisting of cordierite formed, and in some orbicular granitic gneisses, the leucocratic melt formed by melting of quartz and plagioclase in the core, squeezed out from core and crystallized around the core forming outer rim. The hydrothermal fluid at the late stage of magma differentiation penetrated into the orbicular granite gneisses resulting pinitization of cordierite into chlorite and sericite. As Muju orbicula granite gneiss was formed from sedimentary rocks, it is more appropriate to be called Muju orbicula granitic gneiss.