• 제목/요약/키워드: waste disposal

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고준위폐기물 처분시설의 압축 벤토나이트 완충재의 열전도도 추정 (A Prediction of Thermal Conductivity for Compacted Bentonite Buffer in the High-level Radioactive Waste Repository)

  • 윤석;이민수;김건영;이승래;김민준
    • 한국지반공학회논문집
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    • 제33권7호
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    • pp.55-64
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    • 2017
  • 심층 처분방식은 고준위폐기물을 처분하기 위한 가장 적합한 대안으로 고려되어지고 있다. 심층 처분시설은 지하 500~1,000m 깊이의 암반층에 설치되며 심층 처분시스템의 구성 요소로는 처분용기, 완충재, 뒷채움 및 근계 암반이 있다. 이 중 완충재는 심층 처분시스템에 있어 매우 중요한 역할을 한다. 완충재는 지하수 유입으로부터 처분용기를 보호하고, 방사성 핵종 유출을 저지한다. 처분용기에서 발생하는 고온의 열량이 완충재로 전파되기에 완충재의 열적 성능은 처분시스템의 안정성 평가에 매우 중요하다고 할 수 있다. 따라서 본 연구에서는 국내 경주산 압축 벤토나이트 완충재에 대한 열전도도 추정 모델을 개발하고자 하였다. 압축 벤토나이트 완충재의 열전도도는 비정상 열선법을 이용하여 다양한 함수비와 건조밀도에 따라 측정하였으며, 총 39개의 실험 데이터를 토대로 회귀분석을 이용하여 경주 압축 벤토나이트의 열전도도 추정 모델을 제시하였다.

Analyses on Thermal Stability and Structural Integrity of the Improved Disposal Systems for Spent Nuclear Fuels in Korea

  • Lee, Jongyoul;Kim, Hyeona;Kim, Inyoung;Choi, Heuijoo;Cho, Dongkeun
    • 방사성폐기물학회지
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    • 제18권spc호
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    • pp.21-36
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    • 2020
  • With respect to spent nuclear fuels, disposal containers and bentonite buffer blocks in deep geological disposal systems are the primary engineered barrier elements that are required to isolate radioactive toxicity for a long period of time and delay the leakage of radio nuclides such that they do not affect human and natural environments. Therefore, the thermal stability of the bentonite buffer and structural integrity of the disposal container are essential factors for maintaining the safety of a deep geological disposal system. The most important requirement in the design of such a system involves ensuring that the temperature of the buffer does not exceed 100℃ because of the decay heat emitted from high-level wastes loaded in the disposal container. In addition, the disposal containers should maintain structural integrity under loads, such as hydraulic pressure, at an underground depth of 500 m and swelling pressure of the bentonite buffer. In this study, we analyzed the thermal stability and structural integrity in a deep geological disposal environment of the improved deep geological disposal systems for domestic light-water and heavy-water reactor types of spent nuclear fuels, which were considered to be subject to direct disposal. The results of the thermal stability and structural integrity assessments indicated that the improved disposal systems for each type of spent nuclear fuel satisfied the temperature limit requirement (< 100℃) of the disposal system, and the disposal containers were observed to maintain their integrity with a safety ratio of 2.0 or higher in the environment of deep disposal.

초등학교 과학실에서 발생하는 화학폐기물에 대한 실태 (A Status on the Chemical Waste in Elementary School Science Laboratory)

  • 김성규;허승현
    • 한국환경과학회지
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    • 제13권3호
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    • pp.301-311
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    • 2004
  • The purpose of this study was to examine teachers’ awareness of chemical waste produced in elementary school laboratory experimentation and how this awareness relates to collection and disposal of chemical waste. More specifically, the study looked at the correlation between the handling of chemical waste and factors such as years of teachers’ educational career, class size and amount of waste produced. The target population were 250 elementary school teachers in Gyeongnam area and 237 subjects were responded. Among the 237 responses, 37 cases that did not complete the questionnaire were eliminated. Therefore, 200 responses were analyzed in this study. The survey questionnaire consisted of 15 questions. The categories of the questionnaire were their skills of management and treatment of the chemical waste. The data collected were analyzed by SPSS 10.0, and the relations among variables such as class sizes and years of teaching experience were also analyzed by $x^2-test.$ The results in this study were as follows: First, there were no significant differences between the years of teaching and class sizes in the training experience of chemical waste disposal. Second, there was a significant difference between the science laboratory size and class sizes in the laboratory actual condition. In addition, in the relations between the number of times of experimentation and the years of teaching experience, there was a significant difference. Third, in terms of the discharge amount of chemical waste, there was a significant difference between the years of teaching and class sizes. Fourth, in the simple chemistry waste disposal process in the science laboratory, there also was a significant difference between the kinds of experimental equipments that used in the experimentation and the years of teaching. Based on this study, it was found that great amount of the chemical wastes produced in the science laboratory dumped into the drain and the treatment process of chemical waste was also inattentive. Even the importance of environmental education is emphasized in the elementary education, the basic problems occurred in the science laboratory is disregarded. Therefore, not only students but teachers have to pay attention to the disposal process of chemical waste in the laboratory in order to prevent environment pollution. Furthermore, the efforts of preventing environment pollution are needed such as opening the teacher training course about environment education, minimal use of chemicals, treatment of chemical waste, and so forth.

사용후핵연료봉 밀집을 고려한 심지층처분 개념 분석 (An Analysis of the Deep Geological Disposal Concepts Considering Spent Fuel Rods Consolidation)

  • 이종열;김현아;이민수;김건영;최희주
    • 방사성폐기물학회지
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    • 제12권4호
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    • pp.287-297
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    • 2014
  • 사용후핵연료 또는 고준위폐기물의 안전한 처분을 위하여 지난 수십 년 동안 많은 나라들이 다양한 처분대안을 연구하여 왔다. 본 논문에서는 심지층처분기술에 있어서 사용후핵연료를 직접 처분하는 방안으로서 처분효율 향상을 위한 다양한 방안 중의 하나로 고려할 수 있는 PWR 사용후핵연료 집합체를 해체하여 연료봉을 밀집한 경우에 대한 처분 효율을 분석하였다. 이를 위하여, 우선 사용후핵연료 연료봉 밀집개념과 관련 처분용기 및 심지층처분 개념을 설정하였다. 이 개념에 근거하여 심지층 처분시스템의 공학적방벽 설계에 있어서 가장 중요한 요건인 완충재의 온도 제한요건을 만족시키는지 여부를 확인하기 위하여 각 처분개념 별로 열해석을 수행하였다. 그리고, 처분공 간격, 처분터널 간격 및 처분용기 열발산 면적에 따른 열해석 결과를 바탕으로, 단위처분면적 관점에서의 처분효율을 비교/분석하고 평가하였다. 또한, 사용후핵연료봉을 밀집시킨 경우에 있어서 냉각기간에 따른 처분개념을 분석하였다. 분석결과에 따르면 사용후핵연료봉을 밀집하여 심지층처분하는 경우 처분효율 측면에서 불리한 것으로 판단되었다. 다만, 사용후핵연료의 냉각기간을 70년 이상으로 장기화 할 경우 처분효율은 향상될 것으로 예상되지만, 사용후핵연료의 내구성 및 장기저장에 따른 조건 등 추가적인 분석이 필요하다.

지하공간건설 시 해안인근 담수-해수 혼합대의 지화학적 진화 (Geochemical Evolution of Mixing Zone with Freshwater and Seawater near the Coast Area during Underground Space Construction)

  • 김지연;김병우;권장순;고용권
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제20권7호
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    • pp.90-102
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    • 2015
  • To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO3 type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

심지층 처분시설 설계를 위한 처분터널 및 처분공 간격 분석 (Analysis of the Disposal Tunnel Spacing and Disposal Pit Pitch for the HLW Repository Design)

  • 이종열;김성기;김진웅;최종원;한필수
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2003년도 가을 학술논문집
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    • pp.315-321
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    • 2003
  • 본 연구에서는 고준위 방사성폐기물 심지층 처분시설의 규모 및 layout 설정에 필요한 요소인 처분터널 및 처분공 간격에 대한 분석을 수행하였다. 이를 위하여, 기준 처분개념 및 공학적 방벽개념을 바탕으로 처분터널 및 처분공 단면을 설정하고, 단층 및 복층 개념에 따른 처분동굴의 구조적, 열적 안정성을 분석하였다. 분석 결과를 바탕으로 설계에 있어서 주요한 인자 중의 하나인 굴착량을 최소화할 수 있는 처분동굴 및 처분공 간격을 제안하였다. 향후, 부지에 대한 불확실성을 줄이기 위하여 정확한 부지특성 자료를 통한 상세한 분석이 필요하다.

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서울시 쓰레기의 배출추세와 쓰레기 소각열의 이용에 관한 연구 (A Study on The Trend of Occurrence and The Use Possibility of Mass Burning of Solid Waste in Seoul)

  • 김신도
    • 대한설비공학회지:설비저널
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    • 제15권1호
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    • pp.97-104
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    • 1986
  • This is to supply the basic data for saving energy and the appropriate way of waste disposal. The amount of waste disposed and its heat after burning is guessed to get conclusions. 1. The amount of disposable waste in 1990 in Seoul area is expected to be 2.2kg per man/day, coal ashes (YONTAN) 0.7kg, non-coal ashes 1.5kg. 2. The amount of waste combustible and heat after burning will be increased, and it is useful when the waste has Less than $70\%$ of water. 3. The method to collect waste should be specially organized, because most of the waste collected In Korea Is wet. 4. As the heat emitted from mass burning is $4\times10^{12}kcal/y$ in 1985, it is considered to be in senses of energy saving and the rationnal way of waste disposal. 5. Special concern is needed because the environment contaminated will be polluted in result of burning.

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Chinese buffer material for high-level radiawaste disposal --Basic features of GMZ-l

  • WEN Zhijian
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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    • pp.236-244
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    • 2005
  • Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common feature is the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposal high-level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. The buffer material is expected to maintain its low water permeability, self-sealing property, radio nuclides adsorption and retardation property, thermal conductivity, chemical buffering property, overpack supporting property, stress buffering property over a long period of time. Benotite is selected as the main content of buffer material that can satisfy above. GMZ deposit is selected as the candidate supplier for Chinese buffer material of High Level Radioactive waste repository. This paper presents geological features of GMZ deposit and basic property of GMZ Na bentonite. GMZ bentonite deposit is a super large scale deposits with high content of Montmorillonite (about $75\%$) and GMZ-l, which is Na-bentonite produced from GMZ deposit is selected as reference material for Chinese buffer material study.

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