• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.4
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• pp.243-253
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• 2009

In this study, research status on radionuclide and colloid migration in underground research facilities including KURT (KAERI Underground Research Tunnel) was investigated. Some foreign underground research facilities constructed in crystalline rock formations such as granite were briefly introduced and compared. International joint researches concerned with the radionuclide and colloid migration were investigated particularly for the Grimsel Test Site (GTS) and $\ddot{A}$sp$\ddot{o}$ Hard Rock Laboratory by analyzing major research items, on-going research projects, and future plans.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.3
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• pp.247-258
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• 2004

Two 3-dimensional data processing techniques to predict the fractured zone ahead of a tunnel face by the tunnel seismic survey were proposed so that the geometric formation of the fractured zone could be estimated. The first 3-dimensional data processing technique was developed based on the principle of ellipsoid, The input data needed for the 3D migration can be obtained from the 2-dimensional tunnel seismic prediction (TSP) test where the TSP test should be performed in each sidewall of a tunnel. The second 3-dimensional migration technique that was developed based on the concept of wave travel plane was proposed. This technique can be applied when the TSP is operated with sources in one sidewall of a tunnel while the receivers are installed in both sidewalls. New migration technique was applied to an in-situ tunnelling site. The 3-dimensional migration was performed using measured TSP data and its results were compared with the geological investigation results that were monitored during tunnel construction. This comparison revealed that the proposed migration technique could reconstruct the discontinuity planes reasonably well.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.229-243
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• 2013

An in situ solute migration system was designed and installed in KAERI Underground Research Tunnel (KURT) constructed in the site of Korea Atomic Energy Research Institute (KAERI) in order to investigate the migration and retardation of non-sorbing and sorbing tracers through a rock fracture. The system is composed of three main parts including injection, extraction, and data treatment. For the selection of a water-conducting fracture, boreholes were drilled. The fractures in the drilled boreholes were investigated using borehole image analysis using borehole image processing system (BIPS). The results of BIPS analysis showed that borehole YH 3-1 and YH 3-2 were connected each other. Moreover, hydraulic tests were carried out to determine the test section with connectivity for the in situ experiments. The in situ solute migration experiments were accomplished to understand the migration of solutes through fractures in KURT using non-sorbing tracers which were fluorescein sodium, eosin-B, bromide and sorbing tracers which were rubidium, nickel, zirconium, and samarium.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.255-263
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• 2005

Migration experiments of THO and 237Np have performed through a sampled granite core in Chemlab2 probe at the Aspo hard Rock laboratory. The elution curves of THO were analysed to determine hydraulic properties such as the extent of dispersion effect according to flow rates. The retardation phenomena of the solutes were observed and described with elution curves and migration plumes. After migration test, the rock core was opened, and the remaining radioactivities on the rock fracture surfaces were measured. The transport process was simulated with a two-dimensional channel model. The mass transport process was described with three types of basic processes ; advection, sorption and matrix diffusion. By the combination of these processes, effects of each process on transport were described in terms of elution curves and migration plumes. By comparing the simulation results to the experimental one, it was possible to analyse the retardation effect quantitatively.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.17-25
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• 2007

Research and development for disposal of contaminants including radioactive wastes in deep underground have been carried out from laboratory works. However, validation and reliability of the data from the laboratory are arguing issues because they are not obtained from real disposal situations. Underground research laboratory (URL) is not only a solution to overcome such limitations, but also a valuable facility for performance assessment as an engineering scale. However, it requires much budget, and environmental issues can give rise to social conflicts easily. Such considering points related to URL are discussed as well as current status of worldwide URLs are introduced. Furthermore study plans for solute transport in a small-scale underground research tunnel (KURT), which was authorized recently as an non-radioactive facility in Korea, also described.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.336-336
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• 1998

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.51-58
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• 1996

Underground migration of $^{54}Mn,\;^{60}Co,\;^{85}Sr\;and\;^{137}Cs$ in paddy and upland conditions was studied through two years' greenhouse experiment. At early and late growth stages of rice, soybean, Chinese cabbage and radish, a mixed solution of the radionuclides was applied to the water or soil surfaces of the culture boxes filled with an acidic loamy-sandy soil for the upper 20cm. Soil was sampled in layers upto $15{\sim}20cm$ down after harvest. Soil concentrations of the radionuclides decreased exponentially with increasing soil depth and more than 80% of the radioactivities remained in top $3{\sim}4cm$. The mobility of the radionuclides decreased in the order of $^{85}Sr>^{54}Mn>^{60}Co{\geq}^{137}Cs$. Downward migrations of the radionuclides were the greatest in rice soil and the lowest in soybean soil which was fertilized with the least amount of N, P and K. Differences in depth profiles between two application times indicate that the amount of daily migration from $0{\sim}1cm$ layer to the lower area decreases with increasing time after deposition. By a simultaneous addition of KCl and lime following the earlier application, downward migration in soybean, Chinese cabbage and radish soils changed little or retarded more or less but that in rice soil accelerated a little.

• Nuclear Engineering and Technology
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• v.44 no.1
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• pp.79-88
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• 2012

Migration tests were performed with conservative tracers in a fractured zone that had a single fracture of about 2.5 m distance at the KURT. To interpret the migration of the tracers in the fractured rock, a solute transport model was developed. A two dimensional variable aperture channel model was adopted to describe the fractured path and hydrology, and a particle tracking method was used for solute transport. The simulation tried not only to develop a migration model of solutes for open flow environments but also to produce ideas for a better understanding of solute behaviours in indefinable fracture zones by comparing them to experimental results. The results of our simulations and experiments are described as elution and breakthrough curves, and are quantified by momentum analysis. The main retardation mechanism of nonsorbing tracers, including matrixdiffusion, was investigated.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.4
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• pp.465-479
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• 2023

To ensure the safety of disposal facilities for radioactive waste, it is essential to quantitatively evaluate the performance of the waste disposal facilities by using safety assessment models. This paper addresses the development of the safety assessment model for the underground silo of Wolseong Low-and Immediate-Level Waste (LILW) disposal facility in Korea. As the simulated result, the nuclides diffused from the waste were kept inside the silo without the leakage of those while the integrity of the concrete is maintained. After the degradation of concrete, radionuclides migrate in the same direction as the groundwater flow by mainly advection mechanism. The release of radionuclides has a positive linear relationship with a half-life in the range of medium half-life. Additionally, the solidified waste form delays and reduces the migration of radionuclides through the interaction between the nuclides and the solidified medium. Herein, the phenomenon of this delay was implemented with the mass transfer coefficient of the flux node at numerical modeling. The solidification effects, which are delaying and reducing the leakage of nuclides, were maintained the integrity of the nuclides. This effect was decreased by increasing the half-life and the mass transfer coefficient of radionuclides.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.51-59
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• 1996

In case waste disposal site is to be constructed close to the underground facilities such as LPG storage cavern which is completely maintained by groundwater pressure, it is generally requested that the possibility on leachate contamination of cavern area be reviewed and the countermeasure, if it is estimated cavern area is severely affected by leachate, be taken into consideration. Prediction was performed and leachate control plan was made using by analytical and the numerical analysis on the leachate migration which is likely to happen at the area between the proposed waste disposal site and the underground LPG storage cavern located at the U petrochemical complex. Analytical solutions were obtained by the conservative mass advection-diffusion equation and the effect of advection and dispersion factor on the leachate migration was reviewed through peclet number calculation and the functional relationship between the factors and leachate transport velocity was established, which leads to enable us to predict the leachate transport velocity without difficulties when different parameters (factors) are used for analytical solution. Numerical solutions were obtained by FEM using AQUA2D which is for the simulation of groundwater flow and contaminant transport. 3-D discrete fracture models were simulated and fracture flow analysis was performed and feasibility study on the water-curtain system was conducted through the fracture connectivity analysis in rock mass. As results of those analyses, it was interpreted that the leachate would trespass on the LPG storage cavern area in 30 years from the proposed wate disposal site and the vertical water-curtain system was effective mathod for the prevention of leachate's migration further into the cavern area.