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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
Journal Basic Information
Journal DOI :
The Korean Radioactive Waste Society
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Dec 2008
Volume 6, Issue 3 - Sep 2008
Volume 6, Issue 2 - Jun 2008
Volume 6, Issue 1 - Mar 2008
Selecting the target year
Hydrogeological characteristics of the LILW disposal site
Kim, Kyung-Su ; Kim, Chun-Soo ; Bae, Dae-Seok ; Ji, Sung-Hoon ; Yoon, Si-Tae ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 245~255
Korea Hydro and Nuclear Power Company(KHNP) conducted site investigations for a low and intermediate-level nuclear waste repository in the Gyeong Ju site. The site characterization work constitutes a description of the site, its regional setting and the current state of the geosphere and biosphere. The main objectives of hydogeological investigation aimed to understand the hydrogeological setting and conditions of the site, and to provide the input parameters for safety evaluation. The hydogeological characterization of the site was performed from the results of surface based investigations, i.e geological mapping and analysis, drilling works and hydraulic testing, and geophysical survey and interpretation. The hydro-structural model based on the hydrogeological characterization consists of one-Hydraulic Soil Domain, three-Hydraulic Rock Domains and five-Hydraulic Conductor Domains. The hydrogeological framework and the hydraulic values provided for each hydraulic unit over a relevant scale were used as the baseline for the conceptualization and interpretation of flow modeling. The current hydrogeological characteristics based on the surface based investigation include some uncertainties resulted from the basic assumption of investigation methods and field data. Therefore, the reassessment of hydrostructure model and hydraulic properties based on the field data obtained during the construction is necessitated for a final hydrogeological characterization.
Analysis of the statistical properties for the background fractures in the LILW disposal site of Korea
Ji, Sung-Hoon ; Park, Kyung-Woo ; Kim, Kyoung-Su ; Kim, Chun-Soo ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 257~263
We analyzed the statistical properties for the conductive background fractures in the Low and Intermediate Level Waste(LILW) disposal site to conceptualize of its groundwater flow system. The background fractures were classified to fracture sets based on their trends and plunges that were obtained from the borehole logging data, and then the fracture transmissivity distribution was inferred from the fixed interval hydraulic test results. The fracture size distribution of each fracture set was estimated using the fracture density and fracture mapping data. To verify the analyzed results, we compared observed field data to simulated one from the DFN model that was constructed with the analyzed statistical properties of the background fractures, and they showed a good agreement.
Numerical simulation of groundwater flow in LILW Repository site:I. Groundwater flow modeling
Park, Kyung-Woo ; Ji, Sung-Hoon ; Kim, Chun-Soo ; Kim, Kyung-Su ; Kim, Ji-Yeon ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 265~282
Based on the site characterization works in a low and intermediate level waste(LILW) repository site, the numerical simulations for groundwater flow were carried out in order to understand the groundwater flow system of repository site. To accomplish the groundwater flow modeling in the repository site, the discrete fracture network(DFN) model was constructed using the characteristics of fracture zones and background fractures. At result, the total 10 different hydraulic conductivity(K) fields were obtained from DFN model stochastically and K distributions of constructed mesh were inputted into the 10 cases of groundwater flow simulations in FEFLOW. From the total 10 numerical simulation results, the simulated groundwater levels were strongly governed by topography and the groundwater fluxes were governed by locally existed high permeable fracture zones in repository depth. Especially, the groundwater table was predicted to have several tens meters below the groundwater table compared with the undisturbed condition around disposal silo after construction of underground facilities. After closure of disposal facilities, the groundwater level would be almost recovered within 1 year and have a tendency to keep a steady state of groundwater level in 2 year.
Numerical simulation of groundwater flow in LILW Repository site:II. Input parameters for Safety Assessment
Park, Kyung-Woo ; Ji, Sung-Hoon ; Koh, Yong-Kwon ; Kim, Geon-Young ; Kim, Jin-Kook ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 283~296
The numerical simulations for groundwater flow were carried out to support the input parameters for safety assessment in LILW repository site. As the input parameters for safety assessment, the groundwater flux into the underground facilities during construction, flow rate through the disposal silo after closure of disposal silo and flow pathway from the disposal silo to discharge area were analyzed using the 10 cases groundwater flow simulations. From the total 10 numerical simulation results, the statistics of estimated output were similar to among 10 cases. In some cases, the analyzed input parameters were strongly governed by locally existed high permeable fracture zone at radioactive waste disposed depth. Indeed, numerical simulation for well scenario as a human intrusion scenario was carried out using the hydraulically severe case model. Using the results of well scenario, the input parameters for safety assessment were also obtained through the numerical simulation.
Geochemical characteristics of a LILW repository I. Groundwater
Choi, Byoung-Young ; Kim, Geon-Young ; Koh, Yong-Kwon ; Shin, Seon-Ho ; Yoo, Si-Won ; Kim, Doo-Haeng ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 297~306
This study was carried out to identify the characteristics of hydrochemistry controlling groundwater chemical condition in a repository site of Gyeongju. For this study, 12 bore holes of all monitoring bore holes in the study area were selected and total 46 groundwater samples were collected with depth. In addition, 3 surfacewater samples and 1 seawater sample were collected. For water samples, cations and anions were analyzed. The environmental isotopes(
) were also analyzed to trace the origin of water and solutes. The result of
analysis showed that surface water and groundwater were originated from precipitation. Tritium concentrations of groundwater decreased with depth but high concentrations of tritium indicated that groundwater was recharged recently. The results of ion and correlation analysis showed that groundwater types of the study area were represented by Ca-Na-
, which was caused by sea spray and water-rock interaction. Especially, high ratio of Na content in groundwater resulted from ion exchange. For redox condition of groundwater, the values of DO and Eh decreased with depth, which indicated that reducing condition was formed in deeper groundwater. In addtion, high concentration of Fe and Mn showed that redox condition of groundwater was controlled by the reduction of Fe and Mn oxides.
Geochemical Characteristics of the Gyeongju LILW Repository II. Rock and Mineral
Kim, Geon-Young ; Koh, Yong-Kwon ; Choi, Byoung-Young ; Shin, Seon-Ho ; Kim, Doo-Haeng ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 307~327
Geochemical study on the rocks and minerals of the Gyeongju low and intermediate level waste repository was carried out in order to provide geochemical data for the safety assessment and geochemical modeling. Polarized microscopy, X-ray diffraction method, chemical analysis for the major and trace elements, scanning electron microscopy(SEM), and stable isotope analysis were applied. Fracture zones are locally developed with various degrees of alteration in the study area. The study area is mainly composed of granodiorite and diorite and their relation is gradational in the field. However, they could be easily distinguished by their chemical property. The granodiorite showed higher
content and lower MgO and
contents than the diorite. Variation trends of the major elements of the granodiorite and diorite were plotted on the same line according to the increase of
content suggesting that they were differentiated from the same magma. Spatial distribution of the various elements showed that the diorite region had lower
contents, and higher CaO,
contents than the granodiorite region. Especially, because the differences in the CaO and
distribution were most distinct and their trends were reciprocal, the chemical variation of the plagioclase of the granitic rocks was the main parameter of the chemical variation of the host rocks in the study area. Identified fracture-filling minerals from the drill core were montmorillonite, zeolite minerals, chlorite, illite, calcite and pyrite. Especially pyrite and laumontite, which are known as indicating minerals of hydrothermal alteration, were widely distributed in the study area indicating that the study area was affected by mineralization and/or hydrothermal alteration. Sulfur isotope analysis for the pyrite and oxygen-hydrogen stable isotope analysis for the clay minerals indicated that they were originated from the magma. Therefore, it is considered that the fracture-filling minerals from the study area were affected by the hydrothermal solution as well as the simply water-rock interaction.
A Safety Assessment for the Wolsong LILW Disposal Center: As a part of safety case for the first stage disposal
Park, Joo-Wan ; Yoon, Jeong-Hyun ; Kim, Chang-Lak ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 329~346
Post-closure safety assessment for the Wolsong Low- and Intermediate-level radioactive waste Disposal Center is described. Based on assessment context, closure concept and ground water flow characteristics of the disposal site, brief descriptions are included on the assessment scenarios, models, input parameters and tools. Radionuclide transport modeling in the near-field and far-field, gas generation and transport modeling, human intrusion and biosphere transport are also described briefly. Assessment results for each scenarios are shown to meet the performance criteria of regulatory body. Further and continuous efforts to improve the safety of disposal facility will be made during the construction and operational period.
Radwaste characteristics and Disposal Facility Waste Acceptance Criteria
Sung, Suk-Hyun ; Jeong, Yi-Yeong ; Kim, Ki-Hong ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 347~356
The purpose of Radioactive Waste Acceptance Criteria(WAC) is to verify a radioactive waste compliance with radioactive disposal facility requirements in order to maintain a disposal facility's performance objectives and to ensure its safety. To develop WAC which is conformable with domestic disposal site conditions, we furthermore analysed the WAC of foreign disposal sites similar to the Kyung-Ju disposal site and the characteristics of various wastes which are being generated from Korea nuclear facilities. Radioactive WAC was developed in the technical cooperation with the Korea Atomic Energy Research Institute in consideration of characteristics of the wastes which are being generated from various facilities, waste generators' opinions and other conditions. The established criteria was also discussed and verified at an advisory committee which was comprised of some experts from universities, institutes and the industry. So radioactive WAC was developed to accept all wastes which are being generated from various nuclear facilities as much as possible, ensuring the safety of a disposal facility. But this developed waste acceptance criteria is not a criteria to accept all the present wastes generated from various nuclear facilities, so waste generators must seek an alternative treatment method for wastes which were not worth disposing of, and then they must treat the wastes more to be acceptable at a disposal site. The radioactive disposal facility WAC will continuously complement certain criteria related to a disposal concentration limit for individual radionuclide in order to ensure a long-term safety.
Technical Standards and Safety Review of the Low and Intermediate Level Radioactive Waste Disposal Facility
Cheong, Jae-Hak ; Lee, Kwan-Hee ; Lee, Yun-Keun ; Jeong, Chan-Woo ; Rho, Byung-Hwan ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 357~368
On July 31, 2008, the Government issued the construction and operation permit for the first low and intermediate level radioactive waste disposal facility in the Republic of Korea. In this paper, the fundamental regulatory framework, regulatory requirements and technical standards of the disposal facility are introduced, and the phased review process adopted for evaluation of the safety of the facility is briefly described. The Atomic Energy Act sets forth a stepwise regulatory framework for the whole life-cycle of the disposal facility such as siting, design, construction, operation, closure and institutional control. More detailed regulatory requirements and technical standards are stipulated in the subsequent regulations of the Atomic Energy Act and a series of Notices issued by the Ministry of Eduction, Science and Technology. The Korea Institute of Nuclear Safety, as entrusted by the Ministry under the Atomic Energy Act, conducted safety review on the disposal facility, and evaluated the compliance with relevant criteria in all technical elements(i.e. siting and structural safety, radiological environmental impact, operational safety, systems and components, quality assurance, and total systematic performance assessment, etc.). The overall safety review process can be phased into inception phase, initial review phase, main review phase and completion phase. The review results were reported to and deliberated by the five Sub-committees of the Special Committee on Nuclear Safety, and then reported to the Ministry. The Ministry issued the construction and operation permit of the disposal facility through the deliberation of the review results by the Nuclear Safety Commission. Hereafter, the safety of the repository will be reassured by a series of subsequent regulatory inspections and reviews under the Atomic Energy Act. In addition, the licensee's continuous implementation of the "Safety Promotion Plan" may also enhance the long-term safety of the repository and contribute to build-up the confidence of the safety case.
Site Monitoring and investigation plan for LILW disposal
Baek, Seung-Jong ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 369~385
The purpose of site monitoring and investigation is to offer the basic data for performance assessment and design of low- and intermediate-level radioactive waste(LILW) disposal facility by monitoring variations of main site properties continually in the stage of pre-operation, operation and post-closure. Main contents of site monitoring are as follows. In the stage of pre-operation, suitability evaluation for disposal facility and monitoring for constructing and operating disposal facility are performed. In the operation period, monitoring is performed including surroundings to research the influence to environment with operating disposal facility and operate safely and efficiently. In the post-closure period, monitoring about major site properties is performed to prevent the effect of radioactive waste from disposal facility and to secure long-term safety.
Radiological Environment Investigation of Radioactive Waste Disposal Facility
Baek, Jeong-Seok ; Jeong, Yeui-Young ; Ahn, Sang-Bok ; Kim, Wan ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 6, issue 4, 2008, Pages 387~398
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.