• Tunnel and Underground Space
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• v.25 no.6
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• pp.556-567
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• 2015

The evaluation of THM coupling behavior in deep underground repository condition is essential for the long term safety and stability assessment of high-level radioactive waste repository. In order to develop reliable THM analysis techniques effectively, an international cooperation project, DECOVALEX, is carried out. In DECOVALEX-2015 Task B2, the in situ THM experiment planned to be conducted by JAEA was modeled by the research teams from the participating countries. In this study, a THM coupling technique combining TOUGH2 and FLAC was developed and applied to 1 dimensional THM modeling, in which rock, buffer, and heater are considered. The results were compared with those from other research teams.

• Journal of Ship and Ocean Technology
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• v.3 no.1
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• pp.27-41
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• 1999

The objective of the paper is to study the impact of changing the traditional hull design of bulk carriers by providing them with a double hull while keeping the same deadweight. It is demonstrated that by introducing the double hull the structural reliability is increased throughout the entire life and also the extend of the needed repair is reduced. The results are obtained with recently developed mathematical tools for the reliability assessment of ship hulls subjected to the existence of multiple cracks both in the stiffeners and in the plating and it models the crack growth process. The effect of corrosion is represented as time dependent. The long-term stress range acting on the elements is defined as a function of the local transverse pressure of the internal cargo and outside sea water combined with the stresses resulting from the longitudinal bending of the hull, which is a combined with the stresses resulting from the longitudinal bending of the hull, which is a combineation of horizontal and vertical bending moments. The effect of maintenance actions is modelled as a stochastic process. The results show that a different design of the midship section improves the structural safety and also the economy with respect to structural repair of bulk carriers.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.355-375
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• 2020

Selective accumulation of a photosensitizer and the subsequent response in only the light-irradiated target are advantages of photodynamic diagnosis and therapy. The limited depth of the therapeutic effect is a positive characteristic when treating surface malignancies, such as peritoneal carcinomatosis. For photodynamic diagnosis (PDD), adjunctive use of aminolevulinic acid- protoporphyrin IX-guided fluorescence imaging detects cancer nodules, which would have been missed during assessment using white light visualization only. Furthermore, since few side effects have been reported, this has the potential to become a vital component of diagnostic laparoscopy. A variety of photosensitizers have been examined for photodynamic therapy (PDT), and treatment protocols are heterogeneous in terms of photosensitizer type and dose, photosensitizer-light time interval, and light source wavelength, dose, and dose rate. Although several studies have suggested that PDT has favorable effects in peritoneal carcinomatosis, clinical trials in more homogenous patient groups are required to identify the true benefits. In addition, major complications, such as bowel perforation and capillary leak syndrome, need to be reduced. In the long term, PDD and PDT are likely to be successful therapeutic options for patients with peritoneal carcinomatosis, with several options to optimize the photosensitizer and light delivery parameters to improve safety and efficacy.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.4
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• pp.399-410
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• 2022

The solubility and species distribution of radionuclides in groundwater are essential data for the safety assessment of deep underground spent nuclear fuel (SNF) disposal systems. Americium is a major radionuclide responsible for the long-term radiotoxicity of SNF. In this study, the solubility of americium compounds was evaluated in synthetic groundwater (SynDB3), simulating groundwater from the DB3 site of the KAERI Underground Research Tunnel. Geochemical modeling was performed using the ThermoChimie_11a thermochemical database. Concentration of dissolved Am(III) in Syn-DB3 in the pH range of 6.4-10.5 was experimentally measured under over-saturation conditions by liquid scintillation counting over 70 d. The absorption spectra recorded for the same period suggest that Am(III) colloidal particles formed initially followed by rapid precipitation within 2 d. In the pH range of 7.5-10.5, the concentration of dissolved Am(III) converged to approximately 2×10^-7 M over 70 d, which is comparable to that of the amorphous AmCO₃OH(am) according to the modeling results. As the samples were aged for 70 d, a slow equilibrium process occurred between the solid and solution phases. There was no indication of transformation of the amorphous phase into the crystalline phase during the observation period.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.283-292
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• 2018

Objectives: This study was conducted to identify hazardous factors that reflect the characteristics of the academy and to provide basic data of environmental safety standard. Methods: Heavy metals, volatile organic compounds, formaldehyde, pesticides and phthalates were measured in 20 academies, which were supplementary, music, art and physical education institutes. Results: In case of heavy metals, the 12 locations were detected for lead (Pb) over the standard value, and 15 locations were exceeded for the total heavy metal. In six locations, the concentrations of volatile organic compounds were exceeded the standard value of $400{\mu}g/m^3$, and two locations for formaldehyde were exceeded the standard value of $100{\mu}g/m^3$. The most commonly detected agents in the air dust were chlorpyrifos and diazinon. The concentrations of DEHP, DINP, and DBP were detected and exceeded in several academies, The risk assessment results showed that HCHO as carcinogen had a safety level of 10-7 to 10-6, and DEHP and DINP as non-carcinogens had a safety level as assessed to be under than 0.1. Conclusions: Through the investigation of long-term environmental and health effects related laws on academies, indoor air quality management might be needed because there were cases of exceeding standard.

• Journal of Radiation Protection and Research
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• v.44 no.3
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• pp.118-126
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• 2019

Background: Government conducts environmental radioactivity surveillance for verification purpose around nuclear facilities based on the Nuclear Safety Law and issues a surveillance report every year. This study aims to evaluate the short and the long-term fluctuation of radionuclides detected above MDC and their origins using concentration ratios between these radionuclides. Materials and Methods: Sample media for verification surveillance are air, rainwater, groundwater, soil, and milk for terrestrial samples, and seawater, marine sediment, fish, and seaweed for marine samples. Gamma-emitting radionuclides including $^{137}Cs$, $^{90}Sr$, Pu, $^3H$, and $^{14}C$ are evaluated in these samples. Results and Discussion: According to the result of the environmental radioactivity verification surveillance in the vicinity of nuclear power facilities in 2017, the anthropogenic radionuclides were not detected in most of the environmental samples except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples. Radioactivity concentration ratios between the anthropogenic radionuclides ($^{137}Cs/^{90}Sr$, $^{137}Cs/^{239+240}Pu$, $^{90}Sr/^{239+240}Pu$) were similar to those reported in the environmental samples, which were affected by the global fallout of the past nuclear weapon test, and Pu atomic ratios ($^{240}Pu/^{239}Pu$) in the terrestrial sample and marine sample showed significant differences due to the different input pathway and the Pu source. Radioactive iodine ($^{131}I$) was detected at the range of < $5.6-190mBq{\cdot}kg-fresh^{-1}$ in the gulfweed and sea trumpet collected from the area of Kori and Wolsong intake and discharge. A high level of $^3H$ was observed in the air (Sangbong: $0.688{\pm}0.841Bq{\cdot}m^{-3}$) and the precipitation (Meteorology Post: $199{\pm}126Bq{\cdot}L^{-1}$) samples of the Wolsong nuclear power plant (NPP). $^3H$ concentration in the precipitation and pine needle samples showed typical variation pattern with the distance and the wind direction from the stack due to the gaseous release of $^3H$ in Wolsong NPP. Conclusion: Except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples, anthropogenic radionuclides were below MDC in most of the environmental samples. Overall, no unusual radionuclides and abnormal concentration were detected in the 2017's surveillance result for verification. This research will be available in the assessment of environment around nuclear facilities in the event of radioactive material release.

• Tunnel and Underground Space
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• v.23 no.2
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• pp.99-109
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• 2013

The slopes of open-pit mine are typically designed without considering the reinforcement and support method due to the economical efficiency. However, the long-term stability of final pit slope is needed in some case, therefore the appropriate measures that can improve the stability are required. In this study, the field survey and laboratory test were carried out in S limestone mine. The stability assessment of final pit slope was performed through the stereographic projection method, SMR, and numerical analysis. And countermeasures for stabilization were proposed. The results of analysis show that full scale of slope failure is not expected but the failures of bench slope scale are likely to occur. In oder to increase the stability of bench slope, we suggested the remedial methods as follows: excavating the final pit slope by pre-splitting blasting, placing the wide berm in the intermediate bench slope and installing the horizontal drainage hole in the place of local ground water runoff.

• Journal of Radiation Protection and Research
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• v.43 no.2
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• pp.50-58
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• 2018

Background: In terms of the Level 3 probabilistic safety assessment (Level 3 PSA), ingestion of food that had been exposed to radioactive materials is important to assess the intermediate- and long-term radiological dose. Because the ingestion dose is considerably dependent upon the agricultural and dietary characteristics of each country, the reliability of the assessment results may become diminished if the characteristics of a foreign country are considered. Thus, this study intends to evaluate and analyze the ingestion dose of Korean during a severe accident by completely considering the available agricultural and dietary characteristics in Korea. Materials and Methods: This study uses COMIDA2, which is a program based on dynamic food chain model. It sets the parameters that are appropriate to Korean characteristics so that we can evaluate the inherent ingestion dose of Korean. The results were analyzed by considering the accident date and food category with regard to the $^{137}Cs$. Results and Discussion: The dose and contribution of the food category depicted distinctive differences based on the accident date. Particularly, the ingestion dose during the first and second years depicted a considerable difference by the accident date. However, after the third year, the effect of foliar absorption was negligible and exhibited a similar tendency along with the order of root uptake rate based on the food category. Conclusion: In this study, the agricultural and dietary characteristics of Korea were analyzed and evaluated the ingestion dose of Korean during a severe accident using COMIDA2. By considering the inherent characteristics of Korean, it can be determined that the results of this study will significantly contribute to the reliability of the Level 3 PSA.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.53-60
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• 2018

In particular, the investigation of tendons in PSC Box Girder Bridge should be done in a systematic way. It is important to identify preventative maintenance activities that should be carried out in order to analyze the risk factors by type of representative tensions and to reduce risks in the long term. However, in the current maintenance system, various methodologies for investigating and repairing tensions have been studied, but it is difficult to investigate precisely tensions. Therefore, to apply the risk assessment for screening of tensions to the domestic PSC Box Bridge, we presented a risk matrix evaluation index that is consistent with the state assessment and maintenance system.

• 한국노년학
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• v.41 no.2
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• pp.197-215
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• 2021

This study aims to evaluate Person Centered Care practice and characteristics of care services in Korean long-term care facilities using Dementia Care Mapping as a tool. DCM, systematic observational evaluation tool for measuring dementia patients' QOL, was transformed into self-report rating scale. The process of transforming DCM into a scale of 34 items involves operationalization of DCM concepts and it's adaptation into Korean long-term care practices. Review by research team of Bradford university was added to maintain DCM concept and meaning in this scale. The scale with Cronbach alpha of .88 was surveyed on 343 care workers. Survey result shows PCC value practiced by them is 3.77(of 5 likert scale) and values on each categories of PCC reveal the characteristics of care in Korean facilities; attachment(4.02), comfort(3.95), inclusion(3.89), identity(3.67) and occupation(3.41). Dementia care in Korean facilities focuses on recipients'safety, comfort but lacks individualistic care and the meaningful and fulfilling occupation for patients. Looking at the organizational and individual factors influencing DCM values, the small facilities showed higher PCC values and there are no significant difference in PCC values between public and private facilities. Managers and care workers with career of 1~2 years showed higher PCC values compared to other career ranks and lengthes. This study suggests care practice should be centered on personhood of patients in long-term care facilities, for which introduction of unit care and education of PCC for service providers including support personnel are needed. DCM and Korean DCM scale developed in this study are suggested for the PCC-based assessment on care quality.