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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 14, Issue 2 - Jun 2016
Volume 14, Issue 1 - Mar 2016
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Conceptual Modeling Coupled Thermal-Hydrological-Chemical Processes in Bentonite Buffer for High-Level Nuclear Waste Repository
Choi, Byoung-Young ; Ryu, Ji-Hun ; Park, Jinyoung ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 1~9
DOI : 10.7733/jnfcwt.2016.14.1.1
In this study, thermal-hydrological-chemical modeling for the alteration of a bentonite buffer is carried out using a simulation code TOUGHREACT. The modeling results show that the water saturation of bentonite steadily increases and finally the bentonite is fully saturated after 10 years. In addition, the temperature rapidly increases and stabilizes after 0.5 year, exhibiting a constant thermal gradient as a function of distance from the copper tube. The change of thermal-hydrological conditions mainly results in the alteration of anhydrite and calcite. Anhydrite and calcite are dissolved along with the inflow of groundwater. They then tend to precipitate in the vicinity of the copper tube due to its high temperature. This behavior induces a slight decrease in porosity and permeability of bentonite near the copper tube. Furthermore, this study finds that the diffusion coefficient can significantly affect the alteration of anhydrite and calcite, which causes changes in the hydrological properties of bentonite such as porosity and permeability. This study may facilitate the safety assessment of high-level radioactive waste repositories.
Service-life Prediction of Reinforced Concrete Structures in Subsurface Environment
Kwon, Ki-jung ; Jung, Haeryong ; Park, Joo-Wan ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 11~19
DOI : 10.7733/jnfcwt.2016.14.1.11
This paper focuses on the estimation of durability and service-life of reinforced concrete structures in Wolsong Low- and intermediate-level wastes Disposal Center (WLDC) in Korea. There are six disposal silos located in the saturated environment. The silo concrete is degraded due to reactions with groundwater and chemical attacks, and finally it will lose its properties as a transport barrier. The infiltration of sulfate and magnesium, leaching of potassium hydroxide, and chlorine induced corrosion are the most significant factors for degradation of reinforced concrete structure in underground environment. From the result of evaluation of the degradation time for each factor, the degradation rate of the reinforced concrete due to sulfate and magnesium is
, and it is estimated to take 48,000 years for full degradation while potassium hydroxide is leached in depth of less than 1.5 cm at 1,000 years after the initiation of degradation. In case of chlorine induced corrosion, it takes 1,648 years to initiate corrosion in the main reinforced bar and 2,288 years to reach the lifetime limit of the structural integrity, and thus it is evaluated as the most significant factor.
Evaluation of Percolation Rate of Bedrock Aquifer in Coastal Area
Lee, Jeong-Hwan ; Jung, Haeryong ; Park, Joo-Wan ; Yoon, Jeong Hyoun ; Cheong, Jae-Yeol ; Park, Sun Ju ; Jun, Seong-Chun ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 21~33
DOI : 10.7733/jnfcwt.2016.14.1.21
Estimation of groundwater hydrologic cycle pattern is one of the most critical issues in sustainable management of groundwater resources in coastal area. This study estimated groundwater percolation by using the water balance methodology and hydrogeological characteristics of land use and soil. Evapotranspiration was computed by using the Thornthwaite method, and surface runoff was determined by using the SCS-CN technique. Groundwater storage change was obtained as 229 mm/a (17.8% of the average annual rainfall, 1286 mm/a), with 693 mm/a (60.1%) of evapotranspiration and 124 mm/a (9.6%) of surface runoff. Rainfall and groundwater storage change was highly correlated, comparing with the relationships between rainfall and evapotranspiration, and between rainfall and surface runoff. This result indicates that groundwater storage change responds more sensitively to precipitation than evapotranspiration and surface runoff.
Status Analysis for the Confinement Monitoring Technology of PWR Spent Nuclear Fuel Dry Storage System
Baeg, Chang-Yeal ; Cho, Chun-Hyung ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 35~44
DOI : 10.7733/jnfcwt.2016.14.1.35
Leading national R&D project to design a PWR spent nuclear fuel interim dry storage system that has been under development since mid-2009, which consists of a dual purpose metal cask and concrete storage cask. To ensure the safe operation of dry storage systems in foreign countries, major confinement monitoring techniques currently consist of pressure and temperature measurement. In the case of a dual purpose metal cask, a pressure sensor is installed in the interspace of bolted double lid(primary and secondary lid) in order to measure pressure. A concrete storage cask is a canister based system made of double/redundant welded lid to ensure confinement integrity. For this reason, confinement monitoring method is real time temperature measurement by thermocouple placed in the air flow(air intake and exit) of the concrete structure(over pack and module). The use of various monitoring technologies and operating experiences for the interim dry storage system over the last decades in foreign countries were analyzed. On the basis of the analysis above, development of the confinement monitoring technology that can be used optimally in our system will be available in the near future.
A Study on the Applicability for Primary System Decontamination through Analysis on NPP Decommission Technology and International Experience
Song, Jong Soon ; Jung, Min Young ; Lee, Sang-Heon ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 45~55
DOI : 10.7733/jnfcwt.2016.14.1.45
Decontamination is one of the most important technologies for the decommissioning of NPP. The purpose of decontamination is to reduce the Risk of exposure of the decommissioning workers, and to recycle parts of the plant components. Currently, there is a lack of data on the efficiency of the decontamination technologies for decommissioning. In most cases, the local radiation level can be lowered below a regulatory limitation by decontamination. Therefore, more efficient decontamination technology must be continuously developed. This work describes the practical experiences in the United States and the European countries for NPP decommissioning using these decontamination technologies. When the decommissioning of domestic nuclear power plant is planned and implemented, this work will be helpful as a reference of previous cases.
Calibration Method of the Tomographic Gamma Scan Techniques Available for Accurately Characterizing
Jeong, Sung Yeop ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 57~61
DOI : 10.7733/jnfcwt.2016.14.1.57
The Tomographic Gamma Scan (TGS) technique partitions radioactive waste drums into
voxels and assays both the density and concentration of radioactivity for each voxel thus providing for improved accuracy, when compared to the traditional Non-Destructive Assay(NDA) techniques. It could decrease the degree of precision measurement since there is a trade-off between spatial resolution and precision. This latter drawback is compensated by expanding the Region of Interest (ROI) that differentiates the full energy peaks, which, in turn, results in an optimized degree of precision. The enlarged ROI, however, increases the probability of interference among those nuclides that emit energies in the adjacent spectrum. This study has identified the cause of such interference for the reference nuclide of the TGS technique,
(661.66 keV, half-life 30.5 years), to be
(657.75 keV, half-life 249.76 days). A new calibration method of determining the optimized ROI was developed, and its effectiveness in accurately characterizing
and eliminating the interference was further ascertained.
Prediction of Radionuclide Inventory for the Low- and Intermediate-Level Radioactive Waste Disposal Facility by the Radioactive Waste Classification
Jung, Kang Il ; Jeong, Noh Gyeom ; Moon, Young Pyo ; Jeong, Mi Seon ; Park, Jin Beak ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 63~78
DOI : 10.7733/jnfcwt.2016.14.1.63
To meet nuclear regulatory requirements, more than 95% individual radionuclides in the low- and intermediate-level radioactive waste inventory have to be identified. In this study, the radionuclide inventory has been estimated by taking the long-term radioactive waste generation, the development plan of disposal facility, and the new radioactive waste classification into account. The state of radioactive waste cumulated from 2014 was analyzed for various radioactive sources and future prospects for predicting the long-term radioactive waste generation. The predicted radionuclide inventory results are expected to contribute to secure the development of waste disposal facility and to deploy the safety case for its long-term safety assessment.
Safety Assessment on the Human Intrusion Scenarios of Near Surface Disposal Facility for Low and Very Low Level Radioactive Waste
Hong, Sung-Wook ; Park, Sangho ; Park, Jin Beak ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 14, issue 1, 2016, Pages 79~90
DOI : 10.7733/jnfcwt.2016.14.1.79
The second-stage near surface disposal facility for low and very low level radioactive waste's permanent disposal is to be built. During the institutional control period, the inadvertent intrusion of the general public is limited. But after the institutional control period, the access to the general public is not restricted. Therefore human who has purpose of residence and resource exploration can intrude the disposal facility. In this case, radioactive effects to the intruder should be limited within regulatory dose limits. This study conducted the safety assessment of human intrusion on the second-stage surface disposal facility through drilling and post drilling scenario. Results of drilling and post drilling scenario were satisfied with regulatory dose limits. The result showed that post-drilling scenario was more significant than drilling scenario. According to the human intrusion time and behavior after the closure of the facility, dominant radionuclide contributing to the intruder was different. Sensitivity analyses on the parameters about the human behavior were also satisfied with regulatory dose limits. Especially, manual redistribution factor was the most sensitive parameter on exposure dose. A loading plan of spent filter waste and dry active waste was more effective than a loading plan of spent filter waste and other wastes for the radiological point of view. These results can be expected to provide both robustness and defense in depth for the development of safety case further.