• Title/Summary/Keyword: nuclear waste disposal

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U.S. Policy and Current Practices for Blending Low-Level Radioactive Waste for Disposal (저준위 방사성폐기물의 혼합 관련 미국의 정책과 실제 적용)

  • Kessel, David S.;Kim, Chang-Lak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.14 no.3
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    • pp.235-243
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    • 2016
  • In the near future, many countries, including the Republic of Korea, will face a significant increase in low level radioactive waste (LLW) from nuclear power plant decommissioning. The purpose of this paper is to look at blending as a method for enhancing disposal options for low-level radioactive waste from the decommissioning of nuclear reactors. The 2007 U.S. Nuclear Regulatory Commission strategic assessment of the status of the U.S. LLW program identified the need to move to a risk-informed and performance-based regulatory approach for managing LLW. The strategic assessment identified blending waste of varying radionuclide concentrations as a potential means of enhancing options for LLW disposal. The NRC's position is that concentration averaging or blending can be performed in a way that does not diminish the overall safety of LLW disposal. The revised regulatory requirements for blending LLW are presented in the revised NRC Branch Technical Position for Concentration Averaging and Encapsulation (CA BTP 2015). The changes to the CA BTP that are the most significant for NPP operation, maintenance and decommissioning are reviewed in this paper and a potential application is identified for decommissioning waste in Korea. By far the largest volume of LLW from NPPs will come from decommissioning rather than operation. The large volumes in decommissioning present an opportunity for significant gains in disposal efficiency from blending and concentration averaging. The application of concentration averaging waste from a reactor bio-shield is also presented.

Radiological Environment Investigation of Radioactive Waste Disposal Facility (방사성폐기물 처분시설 주변의 방사선환경조사)

  • Baek, Jeong-Seok;Jeong, Yeui-Young;Ahn, Sang-Bok;Kim, Wan
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.6 no.4
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    • pp.387-398
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    • 2008
  • To obtain base-line data in the low- and intermediate-level radioactive waste disposal facility, radiological environment investigation is required at least two years prior to the facility operation near the disposal facility. The investigation has been performed since January 2007 for the Wolsong LILW disposal center. In this paper, investigation procedure and detailed information obtained for six months in 2008 are described. Based on the current results, future investigation planning is also discussed for the radiological environment management of the disposal facility.

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A Long Term Effect Prediction of Radioactive Waste Repository Facility in Gyeongju (경주시에 대한 중저준위 방사성폐기물처분장 건설 프로그램의 장기적 효과)

  • Oh, Young-Min;Jung, Chang-Hoon
    • Korean System Dynamics Review
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    • v.9 no.2
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    • pp.105-128
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    • 2008
  • City of Gyeongju's referendum finally offered the long-waited low-level radioactive waste disposal site in November 2005. Gyeongju's positive decision was due to the various economic rewards and incentives the national government promised to the city. 300 billion won for an accepting bonus, the location of the headquarter building of the Korean Hydro and Nuclear Power Co., and the accelerator research center and 3.25 trillion won for supporting regional development program implementation. All of the above will affect the city's infrastructure and the citizens' economic and social lives. Population, land use, economic structure, SOC and quality of life will be affected. Some will be very positive, and some will be negative. This research project will see the future of the city and forecast the demographic, economic, physical and environmental changes of the city via computer simulation's system dynamics technique. This kind of simulation will help City of Gyeongju's what to prepare for the future. The population forecasting of the year 2046 will be 662,424 with the waste disposal site, and 327,274 without the waste disposal site in Gyeongju. The waste disposal site and regional supporting program will increase 184,246 Jobs more with 1,605 agriculture and fishery, 5,369 manufacturing shops and 27,577 shops. The population increase will bring 96,726 more houses constructed in the city. Land use will also be affected. More land will be developed. And road, water plant and waste water plant will be expanded as much. The city's financial structure will be expanded, due to the increased revenues from the waste disposal site, and property tax revenues from the middle-class employees of the company, and the high-powered scientists and technologists from the accelerator research center. All in all, the future of the city will be brighter after operating the nuclear waste disposal site inside the city.

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A comprehensive review on clay swelling and illitization of smectite in natural subsurface formations and engineered barrier systems

  • Lotanna Ohazuruike;Kyung Jae Lee
    • Nuclear Engineering and Technology
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    • v.55 no.4
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    • pp.1495-1506
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    • 2023
  • For the safe disposal of high-level radioactive waste using Engineered Barrier Systems (EBS), bentonite buffer is used by its high swelling capability and low hydraulic conductivity. When the bentonite buffer is contacted to heated pore water containing ions by radioactive decay, chemical alterations of minerals such as illitization reaction occur. Illitization of bentonite indicates the alteration of expandable smectite into non-expandable illite, which threatens the stability and integrity of EBS. This study intends to provide a thorough review on the information underlying in the illitization of bentonite, by covering basic clay mineralogy, smectite expansion, mechanisms and observation of illitization, and illitization in EBS. Since understanding of smectite illitization is crucial for securing the safety and integrity of nuclear waste disposal systems using bentonite buffer, this thorough review study is expected to provide essential and concise information for the preventive EBS design.

Water Balance Evaluation of Final Closure Cover for Near- surface Radioactive Wastes Disposal Facility

  • Keunmoo Chang;Park, Joo-Wan;Yoon, Jeong-Hyoun;Park, Heui-Joo;Kim, Chang-Lak
    • Nuclear Engineering and Technology
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    • v.32 no.3
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    • pp.274-282
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    • 2000
  • The simulation of water balance was conducted for suggested four alternative multi-layer cover design of near-surface radioactive waste disposal facility under domestic climate condition. The analysis was also conducted for the most favorable one out of four alternative cover design under conservative scenarios. Until 100 years after closure of disposal vault, the infiltration flux for the most favorable cover design was negligible even under doubling of the ambient precipitation condition. When the degradation of asphalt and geomembrane after 100 years of closure was considered, the infiltration flux significantly increased almost to the design criteria of cover system in I' Aube disposal facility. And it was found that the hydraulic conductivity of bentonite/sand as a bottom barrier should be no greater than 1$\times$10$^{-7}$ cm/sec recommended by U.S. EPA.

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