• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.2
• /
• pp.117-124
• /
• 2023

X-ray diffraction analysis, X-ray fluorescence analysis, thermal differential and thermos gravimetric analysis, cation exchange capacity analysis, and Cesium (Cs), Strontium (Sr) adsorption experiments were performed to investigate the physical and chemical properties of natural zeolite from Guryongpo in Korea. As a result of X-ray diffraction analysis, minerals such as mordenite, heulandite, clinoptilolite, and illite are contained, and as a result of X-ray fluorescence analysis, elements such as SiO₂, Al₂O₃, CaO, K₂O, MgO, Fe₂O₃ and Na₂O are contained, and the cation exchange capacity was 148.6 meq/100 g. As a result of thermal differential and thermos gravimetric analysis, it was confirmed that the thermal stability was excellent up to 600 ℃. As a result of the adsorption equilibrium experiment over time, the equilibrium was reached within 30 min. for Cesium (Cs) and within 8 hr. for Strontium (Sr), and the adsorption rates of Cesium (Cs) and Strontium (Sr) were 80% and 18%, respectively. As a result of the single-component isothermal adsorption experiment, in conformed to the Langmuir model, and the maximum Cesium (Cs) adsorption amount was 131.5 mg/g, which was high, while the Strontium (Sr) maximum adsorption amount was 29.5 mg/g, which was low. In the case of the natural zeolite used in this study, the content of minerals including 8-rings such as clinoptilolite, heulandite, and mordenite is high, showing high selectivity for Cesium (Cs).

• Economic and Environmental Geology
• /
• v.35 no.6
• /
• pp.545-552
• /
• 2002

In order to investigate the influence of nuclear power plant operation on its nearby environment, soil, stream and marine sediment samples were collected in the vicinity of the Youngkwang Nuclear Power Plant in Korea, and analyzed for artificial and natural radionuclide radioactivity. From the analytical result, Cs-137 was detected in most soil samples. but it may have been derived fiom past nuclear weapon tests because Cs-134 having short half-live was not detected. The radioactivities of Cs-137 in the sediment samples were also detected which are within the normal range in the sediments based upon the published literature between 1997 and 1999. For the quality control of radioactivity analysis of environmental samples, sets of marine sediments in the Gamami area were analyzed using two HPGe Gamma-ray Spectroscopes (30% and 45%) according to the geostatistical sampling strategy, and Cs-137 and K-40 results were interpreted by analysis of variance (ANOVA). In the two-way ANOVA, variances derived from the geochemical variation were significant, but errors from sampling and analytical procedures are negligible. In conclusion. all the radioanalytical procedures of this study including sampling are validated to be acceptable.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.4 no.2
• /
• pp.25-34
• /
• 2001

/sup 226/Ra and /sup 228/Ra analysis were carried out at the representative station of Masan Bay from May to August, 1999. The high activities of /sup 226/Ra and /sup 228/Ra in the surface water were appeared in rainy season (August, 1). However, there is no significant variation in concentrations in the other season. A high negative linear correlation between /sup 226/Ra activities and salinity in the surface water suggests that /sup 226/Ra activity in the surface water was controlled by simple mixing between the two end-members low salinity high /sup 226/Ra activity water of inner Bay and a high salinity low /sup 226/Ra activity water of the continental shelf water out of Bay. /sup 226/Ra activities below the surface mixed layer were higher than those of expected level from the /sup 226/Ra versus salinity. And also /sup 228/Ra//sup 226/Ra ratios in the bottom water were lower compared to those in surface water due to the presence of potential source of /sup 226/Ra below the surface mixed layer. However, it is known that /sup 228/Ra compared to /sup 226/Ra is enriched in bottom sediments and pure water. Therefore, the most probable sources for low /sup 228/Ra//sup 226/Ra activity ration is submarine ground water discharge. Further studies are required to quantify the various sources of /sup 226/Ra and /sup 228/Ra and their relative contributions.

• The Journal of the Petrological Society of Korea
• /
• v.18 no.4
• /
• pp.279-291
• /
• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Economic and Environmental Geology
• /
• v.51 no.6
• /
• pp.553-566
• /
• 2018

The occurrence of natural radionuclides like uranium and radon in groundwater was hydrochemically examined based on 40 well groundwaters in Mungyeong area. The range of electrical conductivity (EC) value in the study area was $68{\sim}574{\mu}S/cm$. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from $0.03{\sim}169{\mu}g/L$ (median value, $0.82{\mu}g/L$) and radon concentrations ranged from 70~30,700 pCi/L (median value, 955 pCi/L). Only 1 out of 40 wells (2.5%) showed uranium concentration exceeding the maximum contaminant level (MCL; $30{\mu}g/L$) proposed by the US Environmental Protection Agency (EPA). Radon concentrations of eight wells (20%) exceeded AMCL(Alternative maximum contaminant level) of the US EPA (4,000 pCi/L). Four out of those eight wells even exceeded Finland's guideline level (8,100 pCi/L). When concentrations of uranium and radon were investigated in terms of geology, the highest values are generally associated with granite. The uranium and radon levels observed in this study are low in comparison to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• Tunnel and Underground Space
• /
• v.31 no.5
• /
• pp.309-332
• /
• 2021

Natural barrier systems surrounding the geological repository for the high-level radioactive waste should guarantee the hydraulic performance for preventing or delaying the leakage of radionuclide. In the case of the behavior of a crystalline rock, the hydraulic performance tends to be decided by the existence of discontinuities, so the coupled hydro-mechanical(HM) processes on the discontinuities should be characterized. The discontinuum modelling can describe the complicated behavior of discontinuities including creation, propagation, deformation and slip, so it is appropriate to model the behavior of a crystalline rock. This paper investigated the coupled HM processes in discontinuum modelling such as UDEC, 3DEC, PFC, DDA, FRACOD and TOUGH-UDEC. Block-based discontinuum methods tend to describe the HM processes based on the fluid flow through the discontinuities, and some methods are combined with another numerical tool specialized in hydraulic analysis. Particle-based discontinuum modelling describes the overall HM processes based on the fluid flow among the particles. The discontinuum methods that are currently available have limitations: exclusive simulations for two-dimension, low hydraulic simulation efficiency, fracture-dominated fluid flow and simplified hydraulic analysis, so it could be improper to the modelling the geological repository. Based on the concepts of various discontinuum modelling compiled in this paper, the advanced numerical tools for describing the accurate coupled HM processes of the deep geological repository should be developed.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.2
• /
• pp.107-115
• /
• 2023

Cobalt can be released into the natural environment as industrial waste from the alloying industry and as acid mine drainage, and it is also a radionuclide (⁶⁰Co) that constitutes high-level radioactive waste. Smectite is a mineral that can be useful for adsorption and isolation of this element. In this study, Cheto-type montmorillonite (Cheto-MM), which is the source clays of The Clay Mineral Society (CMS) and already well-characterized, was used. The effect of the adsorption site affected by the presence of interlayer water on the adsorption of cobalt before and after dehydration by heating was evaluated and the adsorption mechanism of cobalt on Cheto-MM was studied by applying adsorption kinetics and adsorption isotherm models. The results showed that the adsorption characteristics changed with dehydration and subsequent shrinkage, and cobalt was found to be adsorbed at the edge of Cheto-MM for about 38% and adsorbed at the interlayer site for about 62%, suggesting that the cobalt adsorption of Cheto-MM is significantly influenced by the interlayer. By applying the adsorption kinetic models, the cobalt adsorption kinetics of Cheto-MM is explained by a pseudo-second-order model, and the concentration-dependent adsorption was best described by the Langmuir isotherm adsorption model. This study provides basic knowledge on the adsorption characteristic of cobalt on montmorillonite with different adsorption sites and is expected to be useful in predicting the adsorption behavior of smectite in high-level radioactive waste disposal sites in the future.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.12 no.3
• /
• pp.217-233
• /
• 2014

Securing the radiological safety is a prerequisite for the safe management of the naturally occurring radioactive materials (NORM) which cannot be reused. This becomes a crucial focus of our R&D efforts upon the implementation of the Act on Protective Action Guidelines against Radiation in the Natural Environment. To secure the safety, the establishment of technical bases and procedures for securing radiological safety related to the disposal of NORM is required. Thus, it is necessary to analyze the characteristics, to collect the data, to have the radiological safety assessment methodologies and tools, to investigate disposal methods and facilities, and to study the effects of the input data on the safety for the NORM wastes. Here, we assess the environmental impact of the NORM waste disposal with respect to the major domestic and foreign NORM characteristics. The data associated with major industries are collected/analyzed and the status of disposal facilities and methodologies relevant to the NORM wastes is investigated. We also suggest the conceptual design concept of a landfill disposal facility and the management plan with respect to the major NORM wastes characteristics. The radionuclide pathways are identified for the atmospheric transport and leachate release and the environmental impact assessment methodology for the NORM waste disposal is established using a relevant code. The assessment and analysis on the exposure doses and excessive cancer risks for the NORM waste disposal are performed using the characteristics of the representative domestic NORM wastes including flying ash, phosphor gypsum, and redmud. The results show that the exposure dose and the excessive cancer risks are very low to consider any radiation effects. This study will contribute to development in the areas of the regulatory technology for securing radiological safety relevant to NORM waste disposal and to the implementation technology for the Act.

• Childhood Kidney Diseases
• /
• v.4 no.1
• /
• pp.63-68
• /
• 2000

Purpose: MCDK is regarded as a common cause of abdominal masses in children. And the presentation of the MCDK is usually a unilateral flank mass in the a newborn. Bialteral disease results in either fetal demise or necessity fer renal replacement therapy at birth. This study is designed to assess the clinical features and natural history of the unilateral multicystic dysplastic kidney. Patients and Methods: From January 1987 to January 2000 data were obtained retrospectively on 57 patients (28 boys and 29 girls, age ranged 1day-11years) who had a diagnosis of multicystic dysplastic kidney. The diagnosis of multicystic dysplastic kidney was confirmed by a combination of ultrasonography and radionuclide scan. Voiding cystourethrogram study in 31 patients were done to determine the condition of the contalateral kidney. Restllts: $84\%$ of the patients were diagnosed before birth by antenatal ultrasonography Clinical manifestations of children with postnatal diagnoses were palpable abdominal mass($3.5\%$), abdominal distension($17\%$), and incidental($10.5\%$). The abnormalities in contralateral kidney were hydronephrosis($21\%$), compensatory hypertrophy($12\%$), simple cyst($2\%$), bifid pelvis($2\%$). Surgical management was performed in 20 patients($35\%$) due to recurrent infection, for diagnostic purpose to differentiate from malignancy and abdominal distention. Follow-up in the remaining 37 patients continued (mean 18 months) and results of sonogram findings were involution change in 23 patients($40\%$) and no interval changes in 13 patient($23\%$). Conclusions : The apparent tendency to regression of the dysplastic kidney and no difference in the number of complications justify a conservative management rather than operative intervention except in associated severe complications such as urinary tract infection or rupture of cysts.

• Clinical and Experimental Pediatrics
• /
• v.45 no.2
• /
• pp.232-239
• /
• 2002

Purpose : Renal cystic diseases comprise a mixed group of heritable, developmental and acquired disorders. Recently the use of imaging modalities such as ultrasonography and radionuclide scanning has increased the detection rate of renal cystic diseases. We studied to review the clinical features and treatment of renal cystic diseases in children. Methods : This study was performed in 95 children with renal cystic diseases in the Department of Pediatrics, Asan Medical Center from October 1989 to June 2001. Results : In 95 patients, there were 55 cases(58.0%) with multicystic dysplastic kidney(MCDK), 19 cases(20.0%) with simple renal cysts, 13 cases(13.7%) with hereditary polycystic kidney diseases( 7 with autosomal recessive type, 5 with autosomal dominant type, 1 with undetermined), 6 cases(6.3%) with renal cysts in tuberous sclerosis and 1 case(1.0%) with medullary cystic disease. All MCDK patients had no renal dysfunction and hypertension during the follow-up period. Three out of 13 with polycystic kidney diseases had progressed to end-stage renal disease during the follow-up period. One case with a simple cyst underwent laparoscopic malsupialization for decompression. Conclusion : Renal cystic diseases have diverse clinicopathologic features and variable prognosis. We emphasize that routine follow-up should be performed to prevent and to detect early treatable complication in renal cystic diseases. Therefore, their natural history and treatment need further investigation and long term follow-up is required.