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Cheong J.-Y.,Korea Radioactive Waste Management Corporation | Hamm S.-Y.,Pusan National University | Lee J.-H.,Pusan National University | Lee K.-S.,Korea Basic Science Institute | And 2 more authors.
Environmental Earth Sciences | Year: 2012

The nitrate of groundwater in the Gimpo agricultural area, South Korea, was characterized by means of nitrate concentration, nitrogen-isotope analysis, and the risk assessment of nitrogen. The groundwaters belonging to Ca-(Cl + NO 3) and Na-(Cl + NO 3) types displayed a higher average NO 3 - concentration (79.4 mg/L), exceeding the Korean drinking water standard (<44.3 mg/L NO 3 -). The relationship between δ 18O-NO 3 - values and δ 15N-NO 3 - values revealed that nearly all groundwater samples with δ 15N-NO 3 - of +7.57 to +13.5‰ were affected by nitrate from manure/sewage as well as microbial nitrification and negligible denitrification. The risk assessment of nitrate for groundwater in the study area was carried out using the risk-based corrective action model since it was recognized that there is a necessity of a quantitative assessment of health hazard, as well as a simple estimation of nitrate concentration. All the groundwaters of higher nitrate concentration than the Korean drinking water standard (<44.3 mg/L NO 3 -) belonged to the domain of the hazard index <1, indicating no health hazard by nitrate in groundwater in the study area. Further, the human exposure to the nitrate-contaminated soil was below the critical limit of non-carcinogenic risk. © 2011 Springer-Verlag. Source

Baik M.H.,Korea Atomic Energy Research Institute | Kim S.S.,Korea Atomic Energy Research Institute | Lee J.K.,Korea Atomic Energy Research Institute | Lee S.Y.,Korea Atomic Energy Research Institute | And 2 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

Sorption experiments for radionuclides such as 14C, 99Tc, 137Cs, 90Sr, 63Ni, and 241Am were conducted using two different groundwaters (GM-1 and SS-5) and solid materials (granodiorite and fracture-filling material) sampled from the Wolsong low- and intermediate-level radioactive waste (LILW) repository, Gyeongju, Korea. The distribution coefficients of the radionuclides, K d's, were obtained and their sorption properties were discussed for each radionuclide. For all sorbing radionuclides, the Kd values for the fracture-filling material were observed to be higher than those for granodiorite regardless of the groundwater. The Kd values were increased in the sequence 99Tc < 14C < 90Sr < 137Cs < 63Ni < 241Am regardless of sorbent types implying that the sorption of radionuclides onto geological media is affected by their chemical behavior in accordance with geochemical environments. Anionic radionuclides such as 14C and 99Tc showed very low Kd values both for the granodiorite and fracture-filling material. The mineralogical composition of the geological media and groundwater conditions was also observed to be important in the sorption of sorbing radionuclides, especially in the case of strongly sorbing radionuclides. © 2009 Akadémiai Kiadó, Budapest, Hungary. Source

Lee B.,Korea Institute of Geoscience and Mineral Resources | Hamm S.-Y.,Pusan National University | Jang S.,Korea Rural Community Corporation | Cheong J.-Y.,Korea Radioactive Waste Management Corporation | Kim G.-B.,Korea Water Resources Corporation
Geosciences Journal | Year: 2014

Climate change has resulted in a gradual increase in the surface temperature and significantly variable precipitation in different regions of the world. Linear regression of the groundwater levels in Korea between 2000 and 2010 revealed a decreasing trend with a slope of -29.2 mm/yr; -29.6 mm/yr in the wet season and -32.0 mm/yr in the dry season. Mann-Kendall and Sen's tests were carried out using the groundwater levels and groundwater temperatures at 78 locations in South Korea between 2000 and 2010. The groundwater levels showed a trend in ~50% of the 78 groundwater level datasets, of which ~70% exhibited a decreasing trend at the 95% confidence level. This decreasing trend in the groundwater levels appears to be related to a change in the precipitation in South Korea because more abundant rainfall in the wet season each year does not contribute significantly to groundwater recharge, whereas less rainfall that occurs in the dry season can cause a decrease in the groundwater level. Linear regression of the groundwater temperatures revealed a slope of 0.1006 °C/yr between 2000 and 2010 with a gentler slope (0.08 °C/yr) in summer (June-September), showing that the increase in surface temperature has an impact on increasing the groundwater temperature. In this situation of climate change in Korea, the paradigm of groundwater management strategy needs to be altered properly. © 2014 The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg. Source

Park J.B.,Korea Radioactive Waste Management Corporation | Kim C.-W.,Korea Hydro and Nuclear Power Co. | Kim S.-H.,FNC Technology | Kim J.Y.,FNC Technology
Annals of Nuclear Energy | Year: 2012

As part of the following-up action pertaining to the construction and operation permit for the first stage of the LILW (Low- and Intermediate-Level Radioactive Waste) repository, the preparation for a large-scale in situ experiment is underway by the Korea Radioactive Waste Management Corporation (KRMC) for a realistic assessment of the characteristics of gas generation after the post-closure phase of a repository. In this paper, we discuss a method of determining the representative composition of simulated dry active waste and a related fabrication plan for this material. After a comparison with experimental gas generation results from Finland, dry active waste content was chosen for a large-scale gas generation experiment. Six different types of materials and details on their simulated dry active waste contents are derived with the total mass and density for both a 200 L and a 320 L drum. © 2011 Elsevier Ltd. All rights reserved. Source

Yoon J.-H.,Korea Radioactive Waste Management Corporation | Choi W.-S.,Korea Atomic Energy Research Institute | Lee S.,Korea Atomic Energy Research Institute | Seo K.-S.,Korea Atomic Energy Research Institute
Nuclear Engineering and Technology | Year: 2011

In Korea, although the concept of dry storage system for PWR spent fuels first emerged in the early 1990s, wet storage inside nuclear reactor buildings remains the dominant storage paradigm. Furthermore, as the amount of discharged fuel from nuclear power plants increases, nuclear power plants are confronted with the problem of meeting storage capacity demand. Various measures have been taken to resolve this problem. Dry storage systems along with transportation of spent fuel either on-site or off-site are regarded as the most feasible measure. In order to develop dry storage and transportation system safety analyses, development of design techniques, full scale performance tests, and research on key material degradation should be conducted. This paper deals with two topics, structural analysis methodology to assess cumulative damage to transportation packages and the effects of an aircraft engine crash on a dual purpose cask. These newly emerging issues are selected from among the many technical issues related to the development of transportation and storage systems of spent fuels. In the design process, appropriate analytical methods, procedures, and tools are used in conjunction with a suitably selected test procedure and assumptions such as jet engine simulation for postulated design events and a beyond design basis accident. Source

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