• 한국방사선학회논문지
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• 제11권1호
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• pp.1-8
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• 2017

원전 해체 이후 원전 부지의 제한적 또는 무제한적 이용에 대해서 미국 NRC는 NUREG-1757 문서를 통해 제한적 또는 무제한적 부지 이용에 관한 방사선학적 기준을 제시하였고 사업자가 제염 및 복원 후 이 선량 기준이 충족됨을 증명할 수 있어야만 부지가 제한적 또는 무제한적으로 해제될 수 있다고 하였다. 이와 관련하여 NRC는 운영허가종료계획서(LTP; License Termination Plan)에 방사선학적 부지 해제 기준 준수를 입증하기 위하여 부지 해제 기준, 부지 특성 평가, 최종 방사선 조사 계획에서 주요 방사선원항, 유도농도기준(DCGL) 등을 기재하도록 하고 있다. 이 논문은 국내 원전 해체에 있어서 참조사례가 될 수 있는 Rancho Seco 원전 해체 사례를 참고 및 절차를 분석함으로써 2017년 영구정지가 예정된 고리 1호기뿐만 아니라 향후 해체 원전 부지의 해제 기준 마련에 있어 사용될 수 있는 방법을 검토하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권6호
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• pp.38-47
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• 2013

This study was performed to identify the optimal operating conditions and to evaluate the xylene removal efficiency, applying in-situ soil flushing with the low concentrated solution of 'Tween 80' at the xylene contaminated site. The pilot scale test site ($5m{\times}5m{\times}3m$), was mainly composed of 'sandy loam', with the average hydraulic conductivity of $9.1{\times}10^{-4}cm\;s^{-1}$. The average xylene concentration of the site was 42.1 mg $kg^{-1}$, which was more than 2.5 times higher than Korea soil pollution warning limit (15 mg $kg^{-1}$). For the soil flushing, 7,800 L of 0.1~0.2% surfactant solution was injected into three injection wells at the average injection time of 9 hr $d^{-1}$ for 10 days, followed by the additional only groundwater injection of 6,000 L. The same amount of the effluent solution was extracted from three extraction wells. From the analysis for xylene concentration of all effluent at 3 extraction wells, total 166 g of xylene was removed by in-situ surfactant flushing. Even though the residual xylene concentrations of 7 soil sampling locations in the test site were different due to the soil heterogeneity, from the comparison of xylene concentration at 7 locations before/after the feasibility test, 53.9% of the initial xylene in the site was removed from three extraction wells (mainly Ext-N and Ext-M well). The results showed that the in-situ soil flushing by using low concentrated 'Tween 80' solution had a great potential to remediate the xylene contaminated site.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.234-243
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• 2021

In the research or project planning for the decommissioning of a nuclear power plant, one of several preparations will be the establishment of a list of potential radionuclides to be considered at the time of characterization or final status surveys. Reliable data for selection of potential radionuclides during the transition period to prepare for decommissioning will depend heavily on historical data at the site or, where possible, sampling analysis. However, during the transition period, direct sampling can be challenging, depending on the circumstances of the site or national regulation. A methodology of selecting potential radionuclides for nuclear facility sites which largely consists of three major processes: production of initial list of radionuclides, selection of the insignificant radionuclide that will be eliminated, and consideration of site characterization or sampling. For developing a preliminary list of potential radionuclides for Kori Unit 1 decommissioning, the list of initial radionuclides was made referring to the technical documents applied at decommissioned NPPs in the U.S and additional reference materials applied until the operation of NPPs in Korea. For the screening of insignificant radionuclides, we applied criterion of less than 0.1% of the amount of radioactivity inventory and confirmed the dose fraction using the RESRAD code. The final suit of radionuclides was established, which should be supplemented by reflecting site characterization and sampling process in the future. Thus, the methodology and results for the selection of potential radionuclides suggested in this paper can give an insight as a future reference to deriving DCGLs in relation to site remediation of decommissioning nuclear plants.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권1호
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• pp.71-81
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• 2011

Cause of contamination in the study area nearby Jang Hang Refinery is dust scattering in refinery stack, and soil washing treatment is one of the proper technologies for soil remediation in this area. Site conditions frequently limit the selection of a treatment process. A treatment technology may be eliminated based on the soil classification or physicochemical characteristics of soil. This study was assessed the soil washing efficiency by conducting of soil characteristic analysis in the vicinity of Jang Hang Refinery Stack within a 2 km radius. Also, it was decided about remedial range with comparative analysis of As in soil by Korean Standard Test Method before/after revision, whereupon As concentration in soil showed a increasing tendency after revision. As a result, the soil washing using the size separation of soil was determined through identifying of As species in the soil. In this site, only particle size distribution and water content of soil can provide the initial means of screening for the potential use of soil washing.

• 방사성폐기물학회지
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• 제20권3호
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• pp.339-347
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• 2022

Major accidents at nuclear power plants generate huge amounts of radioactive waste in a short period of time over a wide area outside the plant boundary. Therefore, extraordinary efforts are required for safe management of the waste. A well-established remediation plan including radioactive waste management that is prepared in advance will minimize the impact on the public and environment. In Korea, however, only limited plans exist to systematically manage this type of off-site radioactive waste generating event. In this study, we developed basic strategies for off-site radioactive waste management based on recommendations from the IAEA (International Atomic Energy Agency) and NCRP (National Council on Radiation Protection and Measurements), experiences from the Fukushima Daiichi accident in Japan, and a review of the national radioactive waste management system in Korea. These strategies included the assignment of roles and responsibilities, development of management methodologies, securement of storage capacities, preparation for the use of existing infrastructure, assurance of information transparency, and establishment of cooperative measures with international organizations.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3559-3570
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• 2023

In the decommissioning of nuclear facilities, Derived Concentration Guideline Level (DCGL) derivation is necessary for the release of the facility after the site remediation, which also needs to be implemented in the stage of establishing a decommissioning planning. In order to derive DCGL, the dose assessment for the receptors can be conducted from residual radioactivity by using RESRAD code. When performing sensitivity analysis on probabilistic parameters, secondary evaluation is performed by assigning a single value for parameters classified as sensitive. However, several options may arise in the handling of nonsensitive parameters. Therefore, we compared the results of the first execution of RESRAD applying probabilistic parameters for each scenario with the results of the second execution applying a single value to sensitive parameters among the probabilistic parameters. In addition, we analyzed the effect of setting options for non-sensitive parameters. As a result, the effect on DCGL were different depending on the application scenario, the target radionuclides, and the input parameter selections. In terms of the overall evaluation period, the DCGL graph of the default option was generally shown as the most conservative except for some radionuclides. However, it will not necessarily be given priority in the aspect of the need to reflect site characteristics. The reason for selecting a probabilistic parameter is the availability of the parameter and the uncertainty of applying a single value. Therefore, as an alternative, it can be consistently applied to distribution as an option for non-sensitive parameters after sensitivity analysis.

• 유기물자원화
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• 제27권3호
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• pp.63-74
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• 2019

본 연구에서는 대규모 철도부지를 상업부지로 개발함에 따라 과거 부지 내부에 산업 폐기물 등이 부적절하게 처리되어 중금속 폐기물로 오염된 토양의 Cu, Pb, Zn, Ni 에 대한 인체 위해성 평가를 수행하였다. 위해성 평가는 토양의 복원 및 복원과정에서 필요한 고려요소를 도출하는데 주요한 과정이다. 본 연구에서는 위해성 평가를 위해 환경부 위해성평가지침을 준용하여 노출농도 결정, 노출량 산정, 발암 및 비발암 위해도를 결정하였다. 이를 통해 철도부지의 중금속 오염토양의 인체 위해성 평가 결과를 제시하였다. 노출농도 산정결과 토양내 중금속 함량은 621.3 Cu mg/kg, 2,824.5 Pb mg/kg, 1,559.1 Zn mg/kg, 45 Ni mg/kg이고, 독성금속별 인체 노출량 결과, 노출경로별로는 토양의 실외비산 > 토양섭취 > 토양 접촉 순으로 나타났으며, 오염물질별로는 Pb > Zn > Cu > Ni 순으로 나타났다. 발암위해도 평가 결과, USEPA에서 제시한 허용발암위해도(TCR > $10^{-6}$) 보다 높게 나타났으며, 독성위해도(비발암성) 평가 결과, HI 지수(HI< 1.0)도 성인 3.5, 어린이 4.85, Cu 1.94 ~ 2.16, Pb 1.37 ~ 2.90으로 나타났다. 따라서 대상부지의 중금속으로 오염된 토양의 복원관리가 필요할 것으로 판단된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.149-156
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• 1999

In the United States (U.S.), the monitored natural attenuation (MNA) approach has been used as an alternative remedial option for organic and inorganic compounds retained in soil and dissolved in groundwater. The U.S. Environmental Protection Agency (EPA) defines the MNA as“in-situ naturally-occurring processes include biodegradation, diffusion, dilution, sorption, volatilization, and/or chemical and biochemical stabilization of contaminants and reduce contaminant toxicity, mobility or volume to the levels that are protective of human health and the environment”. The Department of Soil Environment. National Institute Environmental Research (NIER) is in the process for demonstrating the MNA approach as a potential remedial option for the BTEX contaminated site in Uiwang City. The project is charactering the research site in terms of the nature and extend of contamination, biological degradation rate, and geochemical and hydrological properties. The microbial-degradation rate and effectiveness of nutrient and redox supplements will be determined through laboratory batch and column tests. The geochemical process will be monitored for determining the concentration changes of chemical species involved in the electron transfer processes that include methanogenesis, sulfate and iron reduction, denitrification, and aerobic respiration. Through field works, critical soil and hydrogeologic parameters will be acquired to simulate the effects of dispersion, advection, sorption, and biodegradation on the fate and transport of the dissolved-phase BTEX plume using Bioplume III model. The objectives of this multi-years research project are (1) to evaluate the MNA approach using the BTEX contaminated site in Uiwang City, (2) to establish a standard protocol for future application of the approach, (3) to investigate applicability of the passive approach as a secondary treatment remedy after active treatments. In this presentation, the overall picture and philosophy behind the MNA approach will be reviewed. Detailed discussions of the site characterization/monitoring plans and risk-based decision-making processes for the demonstration site will be included.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권spc호
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• pp.99-112
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• 2022

From early 2000, many researchers in the groundwater and soil environment remediation project tried to calculate the pollution level and pollution remediation cost and reflect it in the design. In addition, by identifying the movement characteristics of oil pollutants in the underground environment, many researchers tried to derive design factors necessary for pollution purification. However, although the test should be conducted in an area contaminated with oil, the toxicity and risk are too great for testing by deliberately leaking pollutants that are harmful to the human body. And as oil-contaminated areas are promoted by military units such as returned US military bases, there is a limit to access by the general public. In addition, since the indoor simulation test and the field application test have been carried out separately from each other, it was difficult to compare and review various simulation tests Therefore, in this study, PITT (Partitioning Interwell Tracer Test) and analysis methods were specifically presented through actual tests so that field workers could easily use them with the help of the military base and the Korea Rural Community Corporation Soil Environment Restoration Team. However, in order to directly reflect the distribution tracer test results in the pollution remediation design, it is necessary to reduce the analysis errors by comparing the analysis results of the existing soil pollution survey, physical exploration, and numerical modeling. In addition, it is judged to be cautious in the analysis because errors can easily occur due to various factors such as the type of oil at the polluted site, the hydraulic conductivity of the aquifer, and the skill of the researcher.

• 지질공학
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• 제33권3호
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• pp.371-388
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• 2023

지층구성이 복잡하고 저투수성의 토양이 분포하는 경우 정화효율은 급격히 저하되고 실질적인 정화가 이루어지지 않거나 정화기간이 증가하는 등의 문제가 발생한다. 효율적인 정화를 위해서는 투수성이 개선되어 오염된 구간으로 정화제 주입하여 오염물질과 충분한 접촉이 이루어져야 한다. 본 연구는 균열형성과 효과적인 정화제 유도를 위해 플라즈마 블라스팅, 공압파쇄, 진공추출을 복합적으로 활용하는 PPV 공법의 유체 전달특성을 분석하고 기존공법과의 비교를 통해 개선효과를 평가하였다. 연구는 TPH(Total petroleum hydrocarbons)로 오염된 실제 오염부지에 대한 정화제 전달효과를 확인하기 위한 실증시험을 수행하였으며 정화제의 전달특성과 영향범위 등을 산정하기 위해 주입량과 주입시간을 모니터링하고, 정성적인 지중환경 변화요인을 확인하고자 전기비저항탐사를 수행하였다. 또한, 투수시험을 수행하여 각 공법에 대한 투수성 변화를 평가하였다. 정화제의 주입량 모니터링 결과, 주입량은 대조군 대비 실험군의 주입량이 약 4.74~7.48배 증가하였고, 단위 시간 당 주입 유량(L/min)은 약 5.00~7.54배 실험군의 전달률이 빠른 것으로 분석되었다. 전기비저항탐사 결과, 실험군의 비저항변화비는 대조군과는 달리 지표까지 영향을 주어 비저항값이 전체적으로 감소하는 경향을 보인다. 따라서 실험군은 지표 상부에 분포하는 토사층까지 과산화수소 등의 유체 확산이 이루어져 저비저항 변화비가 감소하는 것을 볼 수 있으며 주입정과 추출정 사이의 수평적 변화비는 약 1.12~2.38배 비저항값이 감소되었다. 투수성의 경우, 대조군과 실험군 모두 유사한 초기 투수성을 보였으나 과산화수소의 정화기작 영향으로 투수성이 감소하는 특성을 나타내는 것으로 확인되었다. 수리전도도의 변화를 정량적으로 평가하면, 대조군은 시험 종료 후 초기 수리전도도 대비 21.1%의 수리전도도를 나타내어 투수성이 급격히 저하되는 양상을 보였으나 실험군은 실험종료 후 초기치 대비 81.3%로 초기 수리전도도와 근접한 값을 나타내는 것으로 파악되었다. 현장조사로 확인된 수리전도도와 정화재 주입실험을 통한 정화제 주입용량(m³/hr), 토양특성분석(함수비, 밀도)을 통한 공극률(%)의 분석을 통해 영향반경(ROI)을 산정산 결과, PPV 공법의 영향반경(ROI)은 대조군에 비해 평균 220% 개선되는 것으로 확인되었다. 이와 같은 성과는 PPV 공법 적용으로 인하여 기존공법 대비 보다 넓은 범위에 걸쳐 효율적인 정화제 전달이 가능하고 정화기작에서 나타나는 투수성 저해요인을 상당부분 극복할 수 있으며, 약 2배 이상의 영향반경 증대를 통해 정화효율을 높일 수 있음을 지시하는 중요한 지표로 볼 수 있다.