一般行政과 敎育行政의 關係硏究

이원정 제주대학교 1991 논문집 Vol.33 No.1

Educational autonomy is considered to be significant so that educati onal activities fully function as their purposes require. The aim of this study is to clarify the relationships between public administration and educational administration by reviewing historical and institutional changes. Various kinds of literature have been examined and reorganized under three sub-headings;Changes in institutional functions and the causes of change; The independence of educational administration; The debate on the effectiveness of centralization and decentralization. What people have realized throughout history was that absolute authority or autocracy is not helpful to either people or states. The ideas for prevention of a monopoly of powers by a particular man or a particular group resulted in the conclusion that there should be separation of the powers of government, so that each segment may be held in check and balance. The institution of public administration is the result of progressive thinkers and of the long-suffering struggles of an awakened people. Since the two great wars, most states began to modernize the functions of goverment for its efficient management by professionalizing each area. This might be called the advent of the modern administrative state. Educational administration under the control of government dates back to the era of religous reformation, when the states had accepted the ideas of Luther and Calvin aad when goverments had increased the institution of public education in Germany and other European countries. As most states, however, had subordinated educational administration to public administration, there was no autonomy to provide planning or policy making for the achievement of true educational purposes. Educational autonomy is utterly up to the style of each goverment. Britain and the U.S.A. are states which adopted a decentralized system of government, while France and some Socialist Countries have adopted a centralized system. Both centralization and decentralization have advantages and disadvantages. Highly decentralized countries such as the U.S.A. are heading toward centralization so as to get over the weakness of the Federal Government. This is called the 'new centralization'. On the contrar, highly centralized countries, such as eastern socialist countries are directed toward decentralization, so that they may prevent the monopoly of power of a central govenment or dictatorship. This is called a 'new decentralization'. Educational autonomy is realized by advanced political ideas. Under a dictatorship, thr educational system is merely the maid of power. In underdeveloped countries. the abuse of power in piblic administration is a hindrance to educational autonomy. Small sized countries are said to be able to manage their governments effectively under centralization. However, it appears that the political change from centralization to decentralization in Korea is due to the strong opposition to dictatorship. Though the constitution had long urged the protection of autonomy, professional activity and political neutrality in education, it was no more then lip-service. In 1991, local councils and boards of education have been organized under the new decentrarization law . Under present law, pubic administration is still in a superior position to educationl adminstration. Educational administration has many burdens to carry out:It has to sponsor the renovation of educational systems inwardly, and it has to inspire the modification of institutional absurdities outwardly.

Potential Backfill Materials for Deposition Tunnels in a High-Level Waste Repository

Jae Owan Lee,Yohan Cha,Jin-Seop Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

Backfill is one of the main components of engineered barrier in a high-level waste repository. The material selection of the backfill determines the barrier performance of the backfill. Overseas, its related research has been carried out mainly in Sweden, Finland, Canada, and Japan. However, Korea has recently started backfill research, and it is urgent to select a potential material for establishing the concept of backfill material and conducting backfill research. This study reviews NEA report, potential materials for overseas backfill research, advantages and disadvantages of single and mixed backfill materials, cases of license applications in Finland and Sweden for the selection of potential materials for backfill in Korea’s high-level waste repository. The review results indicated that it is reasonable to carry out backfill research according to the following plan: Both single and mixed materials are considered as potential materials for backfill research; experiments and performance studies are conducted with these materials; and, based on the results, a potential material or candidate material for the backfill suitable for the HLW repository in Korea is determined. For this plan, the single material is tentatively selected, as in Sweden, as bentonite with a montmorillonite content of about 40-50%. Then, if the selection criteria for montmorillonite content are determined through experiments and performance studies, we determine the final potential backfill material. As for the mixed backfill material, the bentonite/crushed rock mixture seems to be more advantageous than the bentonite/sand mixture considering the disposing problem of crushed rock generated from tunnel excavation and economic feasibility through its recycling. It is thought that the bentonite used in the bentonite/crushed rock mixture should have a higher montmorillonite content than bentonite used as a single backfill material since the crushed rock acts as an inert material in the mixture. The results of this study can be used as basic data for selecting the backfill material to be applied to the high-level waste repository in Korea, and can be used as a guideline for selecting the potential material required for backfill experiments and performance studies to be carried out in the future.

Dual-structure of Expansive Clays and its Response to Hydro-mechanical Loadings: A Review

Jae Owan Lee,Yohan Cha,Changsoo Lee,Jin-Seop Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Expansive clays (for examples, bentonites) are favored as buffer and backfill materials because of their low hydraulic conductivity, high swelling potential, and good mechanical properties, and are installed in highly compacted blocks in repositories. Compacted expansive clays have a dual-structure system: macrostructural system which is a complex of clay aggregates with the inter-aggregate pores (macropores) which can be filled by either liquids or gases; microstructural system with the intraaggregate pores between or within clay particles (micropores) which is usually considered to be saturated by liquid. Understanding the dual-strucure system of expansive clays is essential for characterizing and modeling multiphysics (stress-strain, swelling pressure, etc.) in buffers and backfills. Existing multiphysics studies of expansive clays, as in non-expansive soils, were mostly conducted with a single structure approach based on the behavior of macropores, and there have been limitations in the comprehensive interpretation and modeling of experimental results. However, with the recent development of measurement techniques, a lot of available information on the pore structure of compacted expansive clays has been reported, and with the results, a dual-structure approach considering both microstructural and macrostructural systems has been increasingly applied to improve the modeling of multiphysics of expansive clays. This study reviewed the dual-structure system of compacted expansive clays, analyzed previous studies on its evolution according to hydromechanical loading (loading-unloading and wetting-drying paths), and based on these, intended to provide technical knowledge and information needed for multiphysics research of expansive clays-based buffer and backfill for the KRS repository.

Validation Teste for Thermal-Hydro-Mechanical Behaviors in the Engineered Barrier System of a HLW Repository - Experiences and Plans

Jae Owan Lee,Won Jin Cho,Pil Soo Hahn 한국암반공학회 2006 한국암반공학회 학술대회 및 세미나 자료집 Vol.- No.-

Longevity Issues in Swelling Clay as a Buffer Material for a HLW Repository

Jae Owan Lee,Won Jin Cho 한국방사성폐기물학회 2008 방사성폐기물학회지 Vol.6 No.1

고준위폐기물처분장의 완충재 물질로 사용되는 팽윤성 점토는 방벽재로서 그 기능을 제대로 발휘하기 위해 오랫동안 물리 화학적으로 안정해야 한다. 팽윤성 점토의 장기건전성 관련인 자들을 검토하고, 처분장 성능에 대한 각 인자의 중요성을 평가하였다. 검토결과, 붕괴 열에 의한 온도상승, 지하수 화학, 콘크리트에 의한 pH 증가, 유기물과 미생물, 방사선 조사 및 기계적 교란은 완충재물질로서 팽윤성 점토의 장기건전성에 중요한 인자임을 확인하였다. 본 연구는 고준위폐기물 처분장에서 팽윤성 점토의 완충재 설계를 위한 기초자료로 유용하게 활용될 것이다. A swelling clay should remain physically and chemically stable for a long time to perform its functions as a buffer material of a high-level waste (HLW) repository. The longevity issues in the swelling clay were reviewed to evaluate their importance in the performance of a repository. The review results suggest that an elevated temperature due to decay heat, groundwater chemistry, high pH environment by concrete, organic matter and microbes, radiation, and mechanical disturbance might significantly affect the long-term performance of a swelling clay as a buffer material. This paper will be used as basic informations to design the swelling clay buffer for a HLW repository.

A Review on Measurement Techniques and Constitutive Models of Suction in Unsaturated Bentonite Buffer

Jae Owan Lee,Seok Yoon,Geon Young Kim 한국방사성폐기물학회 2019 방사성폐기물학회지 Vol.17 No.3

불포화 벤토나이트 완충재의 수분흡입력은 공학적방벽의 수리-역학적 성능평가 및 설계에 있어 매우 중요한 입력인자이다. 본 연구에서는 문헌에 보고된 불포화 다공성매질의 수분흡입력 측정기술과 구성모델을 분석하고, 고준위폐기물처분장의 벤토나이트 완충재에 적합한 수분흡입력 측정기술과 구성모델을 제안하였다. 문헌 분석결과, 벤토나이트 완충재의 수분흡입력은 일반토질보다 훨씬 높은 값을 가지며, 매트릭수분흡입력과 삼투흡입력을 포함하는 총수분흡입력을 측정하여 사용하였다. 벤토나이트 완충재의 수분흡입력 측정에는 상대습도센서를 이용한 측정방법(RH-Cell, RH-Cell/Sensor)이 적합하였으며, 핵종 붕괴열에 의한 온도변화와 측정 소요시간을 고려했을 때에는 RH-Cell/Sensor 방법이 더 선호되었다. 벤토나이트 완충재의 수분보유모델은 실험을 통해 여러 가지 모델이 제안되었지만, 불포화 완충재의 수리-역학적 성능평가 구성모델로는 대부분 van Genuchten모델이 사용되었다. 벤토나이트 완충재의 수분특성곡선은 벤토나이트의 종류, 건조밀도, 온도, 염도, 측정 시 시료상태와 이력과정에 따라 서로 다른 경향을 보였다. 수분보유모델의 선정 및 모델인자 결정에는 신뢰도 향상을 위해 이러한 인자들의 영향이 고려되어야 한다. Suction of unsaturated bentonite buffers is a very important input parameter for hydro-mechanical performance assessment and design of an engineered barrier system. This study analyzed suction measurement techniques and constitutive models of unsaturated porous media reported in the literature, and suggested suction measurement techniques and constitutive models suitable for bentonite buffer in an HLW repository. The literature review showed the suction of bentonite buffer to be much higher than that of soil, as measured by total suction including matric suction and osmotic suction. The measurement methods (RH-Cell, RH-Cell/Sensor) using a relative humidity sensor were suitable for suction measurement of the bentonite buffer; the RH-Cell /Sensor method was more preferred in consideration of the temperature change due to radioactive decay heat and measurement time. Various water retention models of bentonite buffers have been proposed through experiments, but the van Genuchten model is mainly used as a constitutive model of hydro-mechanical performance assessment of unsaturated buffers. The water characteristic curve of bentonite buffers showed different tendencies according to bentonite type, dry density, temperature, salinity, sample state and hysteresis. Selection of water retention models and determination of model input parameters should consider the effects of these controlling factors so as to improve overall reliability.

ADSORPTION OF COPPER BY SOIL-BENTONITE MIXTURE

( Jae Owan Lee ),( Won-jin Cho ),( Chul-hyung Kang ) 한국폐기물자원순환학회 2002 APLAS Vol.2002 No.1

Soil-bentonite mixtures have been considered for the liner material of landfill. Tests were conducted to investigate the chemical buffering effect of bentonite and the adsorption characteristics of copper ion by soil- bentonite mixture. With the bentonite content increased the pH increased and, at a given bentonite content, it had a little increase with increasing the solid-to- solution ratio. The distribution coefficients (K_d) for the copper adsorption showed high values under given experimental conditions. The K_d sharply increased with solution pH at pH>6.5, and it revealed a linear increase with increasing the bentonite content of the mixture. An increase in the solid-to-solution ratio decreased the K_d.

Engineering-scale Test for Validating the T-H-M Behavior of a HLW Repository: Experimental Set-up

Jae Owan Lee,Min Hoon Baik,Won Jin Cho 한국방사성폐기물학회 2004 한국방사성폐기물학회 학술논문요약집 Vol.2 No.1

Hydraulic-Thermal-Mechanical Properties and Radionuclide Release-Retarding Capacity of Kyungju Bentonite

Jae-Owan Lee,Won-Jin Cho,Pil-Soo Hahn 한국방사성폐기물학회 2004 방사성폐기물학회지 Vol.2 No.2

고준위방사성폐기물 처분장의 완충재 후보물질 선정을 위해 경주 벤토나이트를 대상으로 수리특성, 팽윤특성, 열적특성, 역학특성 및 핵종유출 저지특성을 조사하였다. 실험결과, 압축 벤토나이트의 수리전도도는 m/s 이하로 매우 낮았으며 건조밀도가 증가할수록 감소하였다. 팽윤압은 0.66 ㎫∼14.4 ㎫ 사이의 값을 보였으며 건조밀도에 따라 증가하였다. 건조밀도가 1.4 Ms/㎥ ∼ 1.8 Mg/㎥1.4 일때, 열전도도, 열축압축강도 (unconfined compressive strength), 탄성계수 (Young's modulus of elasticity), Poisson 비는 각각 0.80 ㎉/m ∼1.52 ㎉/m , 0.55 ㎫ ∼ 8.83 ㎫, 59 ㎫ ∼ 1275 ㎫, 0.05 ∼ 0.20의 값을 나타내었다. 압축벤토나이트에 대한 핵증 확산계수는 산화 환경에서 측정되었으며, 주어진 실험조건에서 삼중수소 (H-3)는 1.7 /s ∼ 3.4 /s. 양이온 핵종 (Cs, Sr , Ni)은 8.6 /s ∼ 1.3 /s, 음이온 핵종 (I, Tc)은 1.2 /s ∼ 9.5 /s, 악티나이드 핵종은 3.0 /s ∼ 1.8 /s 사이의 값을 나타내었다. 이때 확산계수는 모든 핵종에 대해 압축벤토나이트의 건조밀도가 증가할수록 감소하는 경향을 보였다. Studies were conducted to select the candidate buffer material for a high-level waste (HLW) repository in Korea. This paper presents the hydraulic properties, the swelling properties, the thermal properties, and the mechanical properties as well as the radionuclide release-retarding capacity of Kyungju bentonite as part of those studies. Experimental results showed that the hydraulic conductivities of the compacted bentonite were very low and less than m/s. The values decreased with increasing the dry density of the compacted bentonite. The swelling pressures were in the range of 0.66 MPa to 14.4 ㎫ and they increased with increasing the dry density. The thermal conductivities were in the range of 0.80 ㎉/m to 1.52 ㎉/m . The unconfined compressive strength, Young's modulus and Poison's ratio showed the range of 0.55 ㎫ to 8.83 ㎫, 59 ㎫ to 1275 ㎫, and 0.05 to 0.20, respectively, when the dry densities of the compacted bentonite were 1.4 Ms/㎥ to 1.8 Mg/㎥. The diffusion coefficients in the compacted bentonite were measured under an oxidizing condition. The values were $1.7{\times}10^{-10}/s to 3.4{\times}10^{-10}/s for electrically neutral tritium (H-3), 8.6{\times}10^{-14}/s to 1.3{\times}10^{-12}/s for cations (Cs, Sr, Ni), 1.2{\times}10^{-11}/s to 9.5{\times}10^{-11}/s for anions (I, Tc), and 3.0{\times}10^{-14} /s to 1.8{\times}10^{-13}/s $for actinides (U, Am), when tile dry densities were in the range of 1.2 Mg/㎥ to 1.8 Mg/㎥. The obtained results will be used in assessing the barrier properties of Kyungju bentonite as a buffer material of a repository in Korea.n Korea.

KENTEX Operation and Experimental Results on the Thermal-Hydro-Mechanical Behaviors

Jae-Owan Lee,W.J. Cho 한국방사성폐기물학회 2007 한국방사성폐기물학회 학술논문요약집 Vol.5 No.2