• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제10권1호
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• pp.37-43
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• 2012

Radioactive waste transport package was developed to transport eight drums of low and intermediate level waste(LILW) in accordance with the IAEA and domestic related regulations. The package is classified with industrial package IP-2. IP-2 package is required to undergo a free drop test and a stacking test. After free drop and stacking tests, it should prevent the loss or dispersal of radioactive contents, and loss of shielding integrity which would result in more than 20 % increase in the radiation level at any external surface of the package. The objective of this study is to establish the safety test method and procedure for stacking test and to prove the structural integrities of the IP-2 package. Stacking test and analysis were performed with a compressive load equal to five times the weight of the package for a period of 24 hours using a full scale model. Strains and displacements were measured at the corner fitting of the package during the stacking test. The measured strains and displacements were compared with the analysis results, and there were good agreements. It is very difficult to measure the deflection at the container base, so the maximum deflection of the container base was calculated by the analysis method. The maximum displacement at the corner fitting and deflection at the container base were less than their allowable values. Dimensions of the test model, thickness of shielding material and bolt torque were measured before and after the stacking test. Throughout the stacking test, it was found that there were no loss or dispersal of radioactive contents and no loss of shielding integrity. Thus, the package was shown to comply with the requirements to maintain structural integrity under the stacking condition.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제17권4호
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• pp.405-418
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• 2019

Based on spent fuels characteristics from domestic nuclear power plants and a disposal scenario from the current basic plan for high-level radioactive waste management, an improved disposal system has been proposed that enhances disposal efficiency and economic effectiveness compared to the existing disposal system. For this purpose, two disposal canisters concepts were derived from the length of the spent fuel generated from the nuclear power plants. In the disposal scenario, the acceptable amount of decay heat for each disposal container was determined, taking into account the discharge and disposal times of spent fuels in accordance with the current basic plan. Based on the determined decay heat of the two types of disposal canisters and the associated disposal system, thermal stability analyses were performed to confirm their suitability to the proposed disposal system design requirement and disposal efficiency assessment. The results of this study confirm 20% reduction in the disposal area and 20% increase in disposal density for the proposed disposal system compared to the existing system. These results can be used to establish a spent fuel management policy and to design a viable commercial disposal system.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.99-105
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• 2006

The growing oocytes become progressively capable of resuming meiosis, and full meiotic competence appear when they are about 80% of the size of fully grown oocytes. As hormonal influences vary at different stages of reproductive cycle, the size of oocytes may vary according to the reproductive stages. The present study was designed to compare the diameter between the ovulated and freshly collected immature canine oocytes. The ovulated oocytes were collected 72 hr after ovulation by oviductal tube flushing by laparotomy under general anesthesia. Immature oocytes were collected by ovarian slicing method. Diameter of all oocytes was measured directly using epiflurescence microscope with a calibrated micro-eyepiece micrometer at ${\times}200$ magnification. The thickness of zona pellucida and diameter of cytoplasm were measured separately and recorded. A total of 2209 zona intact oocytes were collected, among them 628 from anestrus, 675 from follicular, 838 from luteal and 68 by fallopian tubes flushing methods. The average number of oocytes was 104.7, 168.8, 119.7 and 11.3 for anestrus, follicular, luteal and fallopian tubes flushing methods, respectively. The average diameters of the ooplasm and oocyte were significantly varied in different reproductive stages as well as with ovulated oocytes (P<0.05). The average diameter of ooplasm and oocyte was 115.6 and 127.7, 143.0 and 162.0, 134.6 and 150.6, 159.6 and 185.6 for anestrus, follicular, luteal and ovulated oocytes, respectively. Highest number of oocytes with larger diameter could be collected from the follicular and luteal stages. In conclusion, the follicular and luteal ovaries are the best sources of oocytes for canine IVM.

• Reproductive and Developmental Biology
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• 제37권1호
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• pp.35-40
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• 2013

The objective of this study was to investigate the effects of abnormal ovarian cycles after superovulation treatment of Holstein Donor Cows. CIDRs were inserted into the vaginas of twenty two head of Holstein cows, regardless of estrous cycle. Superovulation was induced using folliclar stimulating hormone (FSH). For artificial insemination, donor cows were injected with $PGF_2{\alpha}$ and estrus was checked about 48 hours after the injection. Then they were treated with 4 straws of semen 3 times, with 12-hour intervals. Embryos were collected by a non-surgical method 7 days after the first artificial insemination. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. Seventy two point seven percentage of the cows(16/22) had normal resumption of ovarian cyclicity(resumption within 40 days after superovulation), and 27.3%(6/22) had delayed resumption(resumption did not occur until>40 days after superovulation). Delayed resumption Type II(first ovulation did not occur until ${\geq}40$ days after superovulation, i.e. delayed first ovulation 13.6%) were the most common types of delayed resumptions. The mean numbers of total ova from < 10 and $10{\leq}$ of corpora lutea(CL) was $7.8{\pm}1.8$ and $12.7{\pm}2.7$, respectively. The number of transferable embryos differed between < 10 and $10{\leq}$ CL was $5.4{\pm}1.3$ and $8.1{\pm}3.4$, respectively. Four point five percentage of the cows(1/22) did not resumption their ovarian cyclicity until 60 days after superovulation treatment. Diverse researches on the superovulation treatment method that is suitable for high-producing Holstein donor cows would contribute to preventing ovarian cyclicity disorder, as well as to the early multiplication of cows with superior genes by increasing the utilization value of donor cows.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제7권4호
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• pp.213-218
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• 2009

Electrowinning process recovers uranium with actinide elements from spent fuels and is a key step in the Pyroprocessing because of proliferation resistance. An analysis of heat transfer of the Electrowinning cell was conducted to develop basic tool for designing engineering-scale Electrowinner. For the calculation of the heat transfer, ANSYS CFX commercial code was adapted. As a result of the calculation, the vertical Heating Zone length had great effect upon temperature of LiCl-KCl eutectic salt. To maintain constant temperature in the salt, the Heating Zone length should be three times longer than the height of the salt. However, the argon and salt temperatures were barely affected by the Cooling Zone length. The temperature under the Cell cover was mainly influenced by the number of the cooling plates. When the cooling plates were installed more than the number of 5, temperature under the cover was maintained below $250^{\circ}C$. These temperature properties had similar tendency toward the temperature of the Cell which was measured from experiments, Simulated heat transfer information from this study could be used to design engineering-scale Electrowinner.

• Journal of Korean Society of Environmental Engineers
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• 제33권4호
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• pp.281-288
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• 2011

Recently, researches that a variety of contaminants in water are removed by sonolysis technology with oxidation and pyrolysis process from cavitation were conducted. However, there are few studies for sonochemical treatment by a pilot-scale ultrasound system. This research focused on developing pilot-scale ultrasound systems, which could be an continuously effective treatment for a large volumes of contaminants, and demonstrating the feasibility of utilizing these systems to remove naphthalene from groundwater. V-120 type reactor was found to be 1.4~2.2 times higher effective than the normal type. A total of three different pilot scale's systems consisted of installing effluent and irrigation water in order to be a continuos system, including supplemental additives, and applying a V-120 type reactor and a external cooling cycle system. Naphthalene levels treated by three systems were lower than a recommended guideline of naphthalene for drinking water in EPA. Especially, the naphthalene removal efficiencies of PS1 and PS2 systems were over 97%. The pilot-scale continuous ultrasound clean-up system delivered over 84~95% naphthalene removal efficiency for treatment of 10~20 liter of groundwater. In addition, the ultrasound system could be successfully applied to the conditions of artificial and genuine groundwater contaminated with naphthalene.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권1호
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• pp.545-552
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• 2017

Ground subsidence can result in the formation of sinkholes, potholes, settlement of structures, and road subsidence. Road subsidence is described as the sudden collapse of the road surface into subsurface cavities caused by the loss of bearing capacity in the ground, such as the dissolution of limestone by fluid flow in the surface causing the formation of voids leading to subsidence at the surface. Road subsidence occurs about 665 times annually, and this incidence has been increasing until 2013. Damaged underground facilities, management negligence, and lowering of the ground water table have been the causes of road subsidence in Seoul. Seoul metropolitan government announced special management counter plans to relieve the anxieties and make the roads safe for passing. Construction sites, such as excavation works, need to be managed properly because they have strong potential to induce road subsidence. The aim of this study was to identify the main causes of road subsidence and suggest management plans. First, life cycle cost analysis revealed the daytime construction to be more appropriate than nighttime. In addition, by analyzing the limitations of using sand as a backfill material, it is proposed to use a flowable backfill material instead of sand. Finally, to reduce the blind spots, which is a problem in surveying the road pavement conditions of local governments, the road to be managed is divided into several zones, and a specialized agency is selected for each zone and a method of surveying the blind spots through collaboration is suggested.

• Journal of Korean Neurosurgical Society
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• 제37권6호
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• pp.443-448
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• 2005

Objective: A variety of genetic alterations in human glioblastoma comprises signal transduction and cell cycle arrest control of cellular processes. Subtractive hybridization is potentially a faster method for identifying differentially expressed genes associated with a particular disease state. Using the technique of subtraction, we isolated novel genes that are overexpressed in glioblastoma tissue as compared to normal brain tissue. Methods: We evaluated the differential expression of genes in each of hybridizing tester and driver cDNAs to digested 130 clones. After sequencing of 130 clones and homology search, this study performed to determine mRNA expression of the unknown gene, "clone 47", in brain tissue, glioblasoma, and several cancer cell lines by reverse transcription-polymerase chain reaction (RT-PCR). To test the time course for Go-phase arrest, serum stimulation and expression at various times for RT-PCR performed. Results: We identified 23 novel genes by BLAST of the digested 130 clones. The expressions of "clone 47" mRNA of glioblastoma and several cancer lines were significantly higher than normal brain tissues and several normal cell lines. We confirmed the mRNA expression of "clone 47" was up-regulation for $0.5{\sim}1hr$ of WI-38 cell differentiation. Conclusion: The novel gene, "Clone 47" is upregulated in glioblastoma tissue and several cancer cell lines. This gene is time dependent activation during time course of serum stimulation. This result suggests that "clone 47" playa role in brain tumorigenesis and the activation of this "clone 47" may be necessary for the development of cancer.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.15-15
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• 2011

As you know, boron compounds, borax ($Na_2B_4O_5(OH)_4{\cdot}8H_2O$) etc. were known thousands of years ago. As for natural boron, it has two naturally occurring and stable isotopes, boron 11 ($^{11}B$) and boron 10 ($^{10}B$). The neutron absorption $^{10}B$ is included about 19~20% with 80~81% $^{11}B$. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. The mass difference results in a wide range of ${\beta}$ values between the $^{11}B$ and $^{10}B$. The $^{10}B$ isotope, stable with 5 neutrons is excellent at capturing thermal neutrons. For example, it is possible to decrease a thermal neutron required for the nuclear reaction of uranium 235 ($^{235}U$). If $^{10}B$ absorbs a neutron ($^1n$), it will change to $^7Li+^1{\alpha}$ (${\alpha}$ ray, like $^4He$) with prompt ${\gamma}$ ray from $^{11}B$ $^{11}B$ (equation 1). $$^{10}B+^1n\;{\rightarrow}\;^{11}B\;{\rightarrow}\; prompt \;{\gamma}\;ray (478 keV), \;^7Li+4{\alpha}\;(4He)\;\;\;\;{\cdots}\; (1)$$ If about 1% boron is added to stainless steel, it is known that a neutron shielding effect will be 3 times the boron free steel. Enriched boron or $^{10}B$ is used in both radiation shielding and in boron neutron capture therapy. Then, $^{10}B$ is used for reactivity control and in emergency shutdown systems in nuclear reactors. Furthermore, boron carbide, $B_4C$, is used as the charge of a nuclear fission reaction control rod material and neutron cover material for nuclear reactors. The $B_4C$ powder of natural B composition is used as a charge of a control material of a boiling water reactor (BWR) which occupies commercial power reactors in nuclear power generation. The $B_4C$ sintered body which adjusted $^{10}B$ concentration is used as a charge of a control material of the fast breeder reactor (FBR) currently developed aiming at establishment of a nuclear fuel cycle. In this study for new boron compound, silicon boride ceramics for capturing thermal neutrons, preparation and characterization of both silicon tetraboride ($SiB_4$) and silicon hexaboride ($SiB_6$) and ceramics produced by sintering were investigated in order to determine the suitability of this material for nuclear power generation. The relative density increased with increasing sintering temperature. With a sintering temperature of 1,923 K, a sintered body having a relative density of more than 99% was obtained. The Vickers hardness increased with increasing sintering temperature. The best result was a Vickers hardness of 28 GPa for the $SiB_6$ sintered at 1,923K for 1 h. The high temperature Vickers hardness of the $SiB_6$ sintered body changed from 28 to 12 GPa in the temperature range of room temperature to 1,273 K. The thermal conductivity of the SiB6 sintered body changed from 9.1 to 2.4 W/mK in the range of room temperature to 1,273 K.

• Journal of Korean Society of Water and Wastewater
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• 제34권5호
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• pp.323-334
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• 2020

Adsorption by granule activated carbon(GAC) is recognized as an efficient method for the removal of perfluorinated compounds(PFCs) in water, while the poor regeneration and exchange cycles of granule active carbon make it difficult to sustain adsorption capacity for PFCs. In this study, the behavior of PFCs in the effluent of wastewater treatment plant (S), the raw water and the effluents of drinking water treatment plants (M1 and M2) located in Nakdong river waegwan watershed was monitored. Optimal regeneration and exchange cycles was also investigated in drinking water treatment plants and lab-scale adsorption tower for stable PFCs removal. The mean effluent concentration of PFCs was 0.044 0.04 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.037 0.011 PFOA g/L, for S wastewater treatment plant, 0.023 0.073 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.013 0.008 PFOA g/L for M1 drinking water treatment plant and 0.023 0.073 PFHxS g/L, 0.000 0.01 PFOS g/L, 0.011 0.009 PFOA g/L for M2 drinking water treatment plant. The adsorption breakthrough behaviors of PFCs in GAC of drinking water treatment plant and lab-scale adsorption tower indicated that reactivating carbon 3 times per year suggested to achieve and maintain good removal of PFASs. Considering the results of mass balance, the adsorption amount of PFCs was improved by using GAC with high-specific surface area (2,500㎡/g), so that the regeneration cycle might be increased from 4 months to 10 months even if powdered activated carbon(PAC) could be alternatives. This study provides useful insights into the removal of PFCs in drinking water treatment plant.