• Journal of Radiation Industry
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• v.18 no.3
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• pp.183-193
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• 2024

As part of the social response to the radon bed incident in 2018, the Nuclear Safety and Security Commission took measures to collect and dispose of all radon beds. The Waste Management Act provides landfill disposal as one of the disposal methods for natural radioactive product waste, which is one of the NORM wastes. When NORM wastes are landfilled, workers and the public at the landfill site are exposed to radiation through various pathways, such as leaching of radionuclides through soil and groundwater, and multiple exposure factors are involved simultaneously. In order to improve the reliability of radiological impact assessment, the values of main exposure factors should be selected more accurately. Therefore, before developing the main exposure factors for site characteristics, it is necessary to prioritize main exposure factors reflecting domestic characteristics of NORM waste landfills. Therefore, in this study, the main exposure factors for NORM waste landfill were derived using NDD analysis. To derive the main exposure factors, the analysis tool was first selected as RESRAD-ONSITE computer code, and the exposure scenarios were mainly selected as a resident farmer and suburban resident scenario, recreation scenario, and industrial worker scenario. Then, the priority 1 and 2 factors were selected for sensitivity analysis, and a Korean standard model was established to reflect Korean characteristics. Finally, the sensitivity analysis was conducted through NDD, and the main exposure factors were derived based on this. In the resident farmer scenario, the contaminated zone distribution coefficients of ²²⁶Ra, ²¹⁰Pb, ²³²Th, ²²⁸Ra, ²³⁴U, and ²³⁸U, as well as precipitation and evapotranspiration factors, were derived as the main exposure factors. In the suburban resident scenario, the contaminated zone distribution coefficients of ²²⁶Ra, ²¹⁰Pb, ²³²Th, ²²⁸Ra, ²³⁴U, and ²³⁸U, as well as precipitation and evapotranspiration coefficients, were derived as the main exposure factors. In the recreation scenario, the contaminated zone distribution coefficient of ²³²Th was derived as the main exposure factor. For the industrial worker scenario, the erosion rate was derived as the main exposure factor. The main exposure factors for each scenario were analyzed to be different depending on the scenario characteristics. The results of this study can be utilized as a basis for radiological environmental impact assessment of NORM waste landfill in Korea.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.226-233
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• 1999

An experimental study has been performed on natural convection heat transfer with a rapid crust formation in the molten metal pool of a low Prandtl number fluid. Two types of steady state tests, a low and high geometric aspect ratio cases in the molten metal pool, were performed. The crust thickness by solidification was measured 88 a function of boundary surface temperatures. The experimental results on the relationship between the Nusselt number and Rayleigh number In the molten metal pool with a crust formation were compared with existing correlations. The experimental study has shown that the bottom surface temperature of the molten metal layer, in all experiments. is the major influential parameter in the crust formation, duo to the natural convection flow. The Nusselt number of the case without a crust formation in the molten metal pool is greater than that of the case with the crust formation at the same Rayleigh number. The present experimental results on the relationship between the Nusselt number and Rayleigh number In the molten metal pool match well with Globe and Dropkin's correlation. From the experimental results, a now correlation between the Nusslet number and Rayleigh number in the molten metal pool with the crust formation was developed as $Nu=0.0923(Ra)^{0.302}$ ($2{\times}10^4< Ra<2{\times}10^7$).

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2447-2453
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• 2023

The radioactivity concentrations of Naturally Occurring Radioactive Materials (NORM) i.e., ²²⁶Ra, ²³²Th, and ⁴K in various chemical fertilizers being used in the agricultural soil of Pakistan were determined utilizing gamma spectrometry by employing a High Purity Germanium (HPGe) detector. The radioactivity concentrations of ²²⁶Ra, ²³²Th, and ⁴K extended from 2.58 ± 0.8-265.7 ± 8.8 Bq kg^-1, 1.53 ± 0.14-76.6 ± 1.07 Bq kg^-1 and 36.5 ± 1.34-15606.7 ± 30.2 Bq kg^-1 respectively. The radiological hazard parameters such as internal and external indices and annual effective dose rates were calculated, while excessive lifetime cancer risk factors for the indoor and outdoor areas were found in the range from 0.3×10^-3 to 10.723×10^-3 and 0.03×10^-3 to 2.7948×10^-3 of most fertilizers, however, some values were slightly higher than the UNSCEAR (The United Nations Scientific Committee on the Effects of Atomic Radiation) recommended values for potash-containing fertilizers such as MOP (Muriate of Potash).

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3785-3795
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• 2024

The present study concerned with the activity concentrations of natural radionuclides (²³⁸U, ²³⁴U, ²³⁰Th, ²²⁶Ra, ²³²Th, ⁴⁰K and, ²³⁵U) in ten sedimentary rock samples collected from fault zone, Gabal Um Hamd, southwestern Sinai, Egypt. These samples were investigated to study their behavior during a part of geologic time. The activity concentrations were measured using γ-ray spectrometry (HPGe detector). The investigated samples were analyzed for major oxides using the XRF technique. The results demonstrated high average activity concentrations of ²³⁸U, ²³⁴U, ²³⁰Th, ²²⁶Ra, ²³²Th, ⁴⁰K and, ²³⁵U than the worldwide average values as reported by UNSCEAR 2008. Theil diagram showed that there are accumulation and leaching of uranium in some samples in the two sides of the fault zone. It is noticed that the ages of uranium depositions for the samples collected from the downthrown of the fault zone vary from 121.5 to 440.1 ky, while for the sample collected from the upthrown of the fault is 210.9 ky. The ²³⁰Th/²³²Th activity ratios range between 4.55 and 91.04 for downthrown samples and between 4.75 and 6.05 for upthrown samples which are smaller than 20 except for two samples, indicating a contamination of the samples by detrital ²³⁰Th. After subtraction of the detrital ²³⁰Th, the corrected ages for downthrown samples vary from 119.1 to 231.7 ky while for upthrown samples vary from 164.4 to 390 ky.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.37-48
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• 2011

Some industrial minerals used in domestic industries such as monazite, apatite, bauxite, and ilmenite belong to NORM (Naturally Occurring Radioactive Materials) because they show a high radioactivity. Products, semi-products, wastes, and by-products which show higher radioactivity than NORM belong to TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). Apatite used for manufacturing phosphate fertilizer in Namhae Chemical company belongs to NORM, and its by-product, phospo-gypsum, belongs to TENORM. A geological investigation is needed for the future environmental impact assessment of the Namhae Chemical company's site. According to survey results of the Namhae Chemical company's site, soil mineral composition indicated the mixture of minerals derived from the country rock (quartz, feldspar, mica, $l4{\AA}$ mineral, kaolin and amphibole) and minerals from the gypsum open-air storage yard (gypsum and apatite). Soil samples showed average content of U 4.6 ppm and Th 10 ppm, which are similar to average crustal abundances. They also show average contents of $^{40}K$ 191-1,166 Bq/kg, $^{226}Ra$ 15.6-710 Bq/kg, and $^{232}Th$ 17.4-72.7 Bq/kg, which indicate moderate levels of radio nuclide. But $^{226}Ra$ anomaly in the gypsum open storage yard is clearly confirmed and $^{232}Th$ anomaly is also confirmed in the east road side of the factory and nearby mountain areas. Soil external hazard indices ranged 0.24-2.01 with the average 0.54. Although most external hazard indices were lower than 1, which means radiation hazard index to be negligible, 5 samples out of total 40 samples showed higher values than 1, and further detailed investigation is needed.

• Advances in materials Research
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• v.4 no.4
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• pp.215-226
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• 2015

Experiment on roughness and micro pit defects of SUS 430 ferrite stainless steel was investigated in laboratory. The relation between roughness and glossiness with reduction in height, roll surface roughness, emulsion parameters was analyzed. The surface morphology of micro pit defects was observed by SEM, and the effects of micro pit defects on rolling reduction, roll surface roughness, emulsion parameters, lubrication oil in deformation zone and work roll diameter were discussed. With the increasing of reduction ratio strip surface roughness Ra(s), Rp(s) and Rv(s) were decreasing along rolling and width direction, the drop value in rolling direction was faster than that in width direction. The roughness and glossiness were obtained under emulsion concentration 3% and 6%, temperature $55^{\circ}C$ and $63^{\circ}C$, roll surface roughness $Ra(r)=0.5{\mu}m$, $Ra(r)=0.7{\mu}m$ and $Ra(r)=1.0{\mu}m$. The glossiness was declined rapidly when the micro defects ratio was above 23%. With the pass number increasing, the micro pit defects were reduced, uneven peak was decreased and gently along rolling direction. The micro pit defects were increased with the roll surface roughness increase. The defects ratio was declined with larger gradient at pass number 1 to 3, but gentle slope at pass number 4 to 5. When work roll diameter was small, bite angle was increasing, lubrication oil in micro pit of deformation zone was decreased, micro defects were decreased, and glossiness value on the surface of strip was increased.

• The Korean Journal of Pain
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• v.24 no.4
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• pp.226-230
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• 2011

Surgical excision was performed on a 30-years old woman with a painful mass on her left thigh. The pathologic findings on the mass indicated fibromatosis. After the operation, she complained of allodynia and spontaneous pain at the operation site and ipsilateral lower leg. We treated her based on postoperative femoral neuropathy, but symptom was aggravated. We found a large liposarcoma in her left iliopsoas muscle which compressed the lumbar plexus. In conclusion, the cause of pain was lumbar plexopathy related to a mass in the left iliopsoas muscle. Prompt diagnosis of acute neuropathic pain after an operation is important and management must be based on exact causes.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3898-3903
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• 2024

There is a lack of available data on the radioactivity levels of these materials, despite the potential risks they may pose to patients, dental technicians, and dentists. A total of forty samples were collected from different dental markets in Egypt. Using an NaI(Tl) detector, the gamma-ray spectrometer measured the activity levels of uranium-238, radium-226, thorium-232, and potassium-40. The findings revealed that the mean concentration of ²³⁸U (below the minimum detectable activity, MDA), ²²⁶Ra (135 ± 5 and 132 ± 5 Bq/kg), ²³²Th (187 ± 4 and 243 ± 8 Bq/kg), and ⁴⁰K (1560 ± 52 and 2501 ± 89 Bq/kg) in feldspar and zirconia (ZrO₂) dental ceramic samples, respectively, were all within the limits established by the International Organization for Standardization (ISO) and the European Commission (EC). The use of feldspar and zirconia dental ceramics to restore all teeth would result in an estimated maximum beta dose of 1.5 mGy/year to the oral tissue. The results suggest that there is no cause for concern regarding any additional beta dose to the oral cavity from the use of feldspar and zirconia dental ceramics.

• PNF and Movement
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• v.15 no.3
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• pp.217-226
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• 2017

Purpose: The purpose of this study was to determine the effects of a modified abdominal draw-in maneuver on trunk stability and functional capacity as well as pain in patients with chronic low back pain. Methods: The study included 3 patients with chronic low back pain who volunteered to participate. The modified abdominal draw-in maneuver included a posterior pelvic tilt, a traditional abdominal draw-in maneuver, and a vibration sensory feedback device. Voluntary abdominal contraction using the vibration sensory feedback device was performed by the subjects for more than 1 hour per day, 5 times per week, for 6 weeks along with common low back pain treatment. Electromyographic signals in the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles were measured to compare muscle activation. The degree of pain was measured using the visual analogue scale (VAS), and functional capacity was measured using the Korea Oswestry Disability Index (K-ODI). All results were compared to the means before and after intervention. Results: After the intervention, the RA, EO, and IO showed increased muscle activation and the ES showed decreased muscle activation. The visual analogue scale decreased after intervention and the K-ODI decreased after intervention. Conclusion: Modified abdominal draw-in maneuvers in daily life combined with therapeutic exercises may be effective in relieving pain and dysfunctions in chronic low back pain patients.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.133-142
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• 2009

In order to understand the present environmental condition and future impingement of Changjiang(Yangtze River) outflow upon the adjacent seas after the scheduled completion of the Sanxia (Three Gorges) Dam in 2009, we tried to estimate the mixing ratios among surface waters of three end-members: Changjiang Water (CW), Kuroshio Water (KW), and East China Sea Water (ECSW) using $^{228}Ra/^{226}Ra$ activity ratio and salinity as tracers. Water samples were collected from 32 stations in November 2005 (R/V Tamgu 3), from 20 stations in July 2006 (R/V Ocean 2000) and from 17 stations in August 2006 (R/V Ieodo) in the northern part of the East China Sea. Radium isotopes in ~300 liters of surface seawater were extracted onboard by filtering through manganese impregnated acrylic fibers and following coprecipitation as $Ba(Ra)SO_4$. Activities of radium isotopes were determined by a high purity germanium detector. Results show that the fraction of CW was in the range of 1-23% in the study area, while KW was in the range of 0-30 % and ECSW 58-100 %. The eastward plume of Changjiang outflow, commonly observed in satellite images during summer and also displayed by the eastward-decreasing CW fraction in this study, could be attributed to Ekman transport caused by the SE monsoon prevailing in this region during summer. Results of this study showed that in the drought season, there was a little or no fraction of CW in the study area. Concentration of dissolved inorganic nitrogen (DIN) showed strong positive relationship with the fraction of CW, suggesting Changjiang as the major source of nitrogen. The mixing curve of DIN indicates the removal of nitrate by biological uptake during the mixing of CW with ambient seawater in the study area.