• Proceedings of the Korea Society for Simulation Conference
• /
• 2000.11a
• /
• pp.61-66
• /
• 2000

The KEPRI has been upgrading the KNPEC(Korea Nuclear Power Education Center) #2 simulator, a replica of Yonggwang Unit 1 & 2, due to the outdated systems. The scenarios, such as the continuous load change, are selected to verify and validate the simulator, and the data required to V&V are generated with the best-estimated codes, RETRAN and MARS. The reactor coolant system and steam generator system are cut up into volumes and junctions for the accurate model of the scenarios, and other components and control systems are modeled. For the model the operation and design data of the plants is used and in some cases the data of Kori Unit 3 & 4 is used to fill up the lack of required data. The results of some selected analyses with the models are compared with the operating data of the plants to verify the models, and the analyses of the scenarios are carried out to generated the data for the V&V of the simulator

• Nuclear Engineering and Technology
• /
• v.40 no.3
• /
• pp.199-212
• /
• 2008

A small-break loss of coolant accident (SB-LOCA) test with a break size equivalent to a 3-inch cold leg break of the APR1400 was carried out as the first transient integral effect test using the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation). This was the first integral effect test to investigate the integral performance of the test facility and to verify its simulation capability for one of the design-basis accidents. Reasonably good thermal hydraulic data was obtained so that an integral performance of the fluid sub-systems was identified and control performance of the ATLAS was confirmed under real thermal hydraulic conditions. Based on the measured data, a post-test calculation was carried out using the best-estimate thermal hydraulic safety analysis code, MARS 3.1, and the similarity between the expected and actual data was investigated. On the whole, the post-test calculation reasonably predicts the major thermal hydraulic parameters measured during the SB-LOCA test. The obtained data will be used to enhance the simulation capability of the ATLAS and to improve an input model of the ATLAS for simulation of other target scenarios.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.138.2-138.2
• /
• 2012

Cave on the Moon is considered as the most appropriate place for human to live during the frontier lunar exploration. While the lava flows, the outer crust gets cooled and solidified. Then, the empty space is remained inside after lava flow stops. Such empty space is called the lava caves. Those lava tubes on the Earth are formed mostly by volcanic activity. However, the lava tubes on satellite like Moon and planet like Mars without volcanic activity are mostly formed by the lava flow inside of the crater made by large meteorite impact. Some part of lava tube with collapsed ceiling appears as the entrance of the cave. Such area looks like a deep crater so called a pit crater. Four large pit craters with diameter of > 60 m and depth of > 40 m are found without difficulty from Kaguya and LRO mission image archives. However, those are too deep to use as easily accessible human frontier base. Therefore, now we are going to identify some smaller lunar caves with accessible entrances using LRO camera images of 0.5 m/pixel resolution. Earth's lava caves and their entrances are well photographed by surface and aerial camera in immense volume. Thus, if the image data are sorted and archived well, those images can be used in comparison with the less distinct lunar cave and entrance images due to its smaller size. Then, we can identify the regions on the Moon where there exist caves with accessible entrances. The database will be also useful in modeling geomorphology for lunar and Martian caves for future artificial intelligence investigation of the caves in any size.

• Cross-Cultural Studies
• /
• v.34
• /
• pp.201-236
• /
• 2014

Juan $Mars{\acute{e}}$ was born in 1933 in Barcelona. Being the son of a City cleaner, he was able to watch, from a very early age, all the films he desired, as many times as he wished. This privilege meant a great help in future years, when having to develop the plots and characters of his works. In his last (latest) novel, Caligrafía de los $sue{\tilde{n}}os$, published in 2011, as he has done in his previous works he uses a cinematographic frame again. The explicit references to Hollywood's Golden Age -such as John Ford's Stagecoach and Cecil B. DeMiller's The Plainsman- bring very specific and vivid images to the reader's mind, leading to clear physical and psychological associations. The aim is achieved: the reader's attention is caught immediately. However, characters, plot and cinematographic structures are actually distracting mirages. They make the reader expect a predictable ending which, in fact, will be very different. Therefore, the surprised reader must step back, in order to approach the main topics of the novel from a certain distance. Doing so, he's following the Theory of the Distancing Effect. He becomes aware of the need of a new perspective on social problems that he had considered as familiar justo a few moments before. Thus, he is getting prepared for a more objective interpretation, such as the futility of war and the ideological differences that led to the (Spanich) Civil War and all its devastationg effects.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.4
• /
• pp.479-492
• /
• 2019

Objectives: This study aimed to develop the CAMBRA-kids application for the systematic management of dental caries among preschoolers, activate the dental caries management system, and contribute to the dental caries management of preschoolers. Methods: The collected data were analyzed using R studio 1.2.1335 for Windows (RStudio Inc., Boston, MA, USA, 2018). Algorithm evaluation, heuristic evaluation and usability evaluation were analyzed using descriptive statistics. Results: Both expert evaluations of the application's algorithms were calculated as 100%, for proficiency and efficiency. The application worked well with the designed algorithms, the risk group level of participants was categorized appropriately, and the risk management method was guided properly according to the risk group level. Of the five problems presented in the heuristic evaluation, 'the lack of security' and 'the lack of information on oral health care' received 'high severity' scores. The usability evaluation of the application produces an overall score of 3.27. In the subscales (participation, functionality, aesthetics, and information) of the Mobile App Rating Scale (MARS), the 'participation' domain received the lowest score of 2.56 and the 'functional' domain received the highest score of 3.70. Conclusions: The CAMBRA-kids application is expected to be applied and used in the field of preschoolers' oral health care management, and to contribute to the prevention of dental caries of preschoolers by activating the dental caries management system using the application.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.5
• /
• pp.859-871
• /
• 2019

Objectives: The present study aimed to evaluate the usability, quality, and usefulness of the mobile application, CAMBRA-kids, for caries management in preschoolers. Methods: Ninety-one caregivers and preschoolers participated in the user evaluation of CAMBRA-kids. The evaluators assessed the usability, quality, and usefulness of CAMBRA-kids. The collected data were analyzed using R studio 1.2.1335 for Windows (RStudio Inc. 2018, Boston, MA, USA). The evaluations for usability, quality, and usefulness were analyzed with descriptive statistics, Kruskal-Wallis rank sum test, and Wilcoxon rank sum test. Results: On user evaluation, the quality and usefulness of the application scored >3 points, and majority of the users rated the quality and usefulness of the application as high. The quality of the application's system was the highest at 3.68 points, and the actual usage of the application was the lowest at 3.10 points. The application had the highest technological aspect score of 3.20, whereas the content related to oral health information had the lowest score of 3.10/5. Although the application showed no statistically significant differences in the quality and usefulness according to general characteristics, there was a statistically significant difference (p<0.05) between the two when compared between the caries risk group. For all items, the protector of the high-risk group evaluated the quality and usefulness of the application highly. The moderate risk group gave the lowest evaluation score for the application's quality and usefulness. The usability score of the application, according to the user version of the mobile application rating scale (uMARS), was 3.25, and the average engagement score was 2.82 (56.31%). The highest subscale score was 3.63. Conclusions: In this study, we found suitable quality, usability, and usefulness of the mobile application, CAMBRA-kids. In future, the use of this application will contribute to the prevention of dental caries among preschoolers.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.2
• /
• pp.345-349
• /
• 2019

The National Aeronautics and Space Administration (NASA) has long been studying the essential elements of manned planetary exploration and has held several international challenges to encourage the research works related to it. One of them was the NASA Centennial Challenge Programs which started in 2015. Following the second in 2017, the third is currently going on in 2019. Participating "3D-Printed Habitat Challenge", one of the challenges in the second program, this research team designed and developed the 3D printer extruding module for the Lunar Simulant (Korea Hanyang Lunar Simulant-1; KOHLS-1) and the polymer. For optimizing the modul, a cylindrical specimen of ${\varnothing}150{\times}300mm^3$ volume and a specimen of $200{\times}100{\times}650mm^3$ volume were manufactured and their compressive and flexural strengths were tested. The findings can help automatize the space construction in the future.

• Nuclear Engineering and Technology
• /
• v.53 no.10
• /
• pp.3236-3246
• /
• 2021

Lessons learned from the Fukushima Daiichi nuclear power plant accident directed that multiple failures should be considered more seriously rather than single failure in the licensing bases and safety cases because attempts to take accident management measures could be unsuccessful under the high radiation environment aggravated by multiple failures, such as complete loss of electric power, uncontrollable loss of coolant inventory, failure of essential safety function recovery. In the case of the complete loss of electric power called station blackout (SBO), if there is no mitigation action for recovering safety functions, the reactor core would be overheated, and severe fuel damage could be anticipated due to the failure of the active heat sink. In such a transient condition at CANDU-6 plants, the seal failure of the primary heat transport (PHT) pumps can facilitate a consequent increase in the fuel sheath temperature and eventually lead to degradation of the fuel integrity. Therefore, it is necessary to specify the regulatory guidelines for multiple failures on a licensing basis so that licensees should prepare the accident management measures to prevent or mitigate accident conditions. In order to explore the efficiency of implementing accident management strategies for CANDU-6 plants, this study proposed a realistic accident analysis approach on the SBO transient with multiple-failure sequences such as seal failure of PHT pumps without operator's recovery actions. In this regard, a comparative study for two PHT pump seal failure modes with and without coolant seal leakage was conducted using a best-estimate code to precisely investigate the behaviors of thermal-hydraulic parameters during transient conditions. Moreover, a sensitivity analysis for different PHT pump seal leakage rates was also carried out to examine the effect of leakage rate on the system responses. This study is expected to provide the technical bases to the accident management strategy for unmitigated transient conditions with multiple failures.

• Food Science and Industry
• /
• v.49 no.4
• /
• pp.40-63
• /
• 2016

John Glenn, America's first man to eat anything in the near-weightless environment of Earth orbit, found the task of eating fairly easy. With improved packaging came improved food quality and menus. By the time of the Apollo Program, the quality and variety of food increased even further. Apollo astronauts were the first to have hot water, which made rehydrating foods easier and improved the food's taste. Thermostabilized pouches were also introduced on Apollo. The task of eating in space got a big boost in Skylab. It also had a food freezer and refrigerator a convenience offered by no other vehicle before or since. Two different food systems will be used for future long-duration missions to other planets, one for traveling to and from the distant body and one for use on the surface of the moon or Mars. The transit food system will be similar to the space station food system with the exception that products with three-to five-year shelf lives will be needed. Thus, this part of the trip will be similar to what occurs aboard space missions now. The surface food system, be it lunar or planetary, will be quite different. It will be similar to a vegetarian diet that someone could cook on Earth. Once crew members arrive on the surface and establish living quarters, they can start growing crops. Once the crops are processed into edible ingredients, cooking will be done in the spacecraft's galley to make the food items. Disposal of used food packaging will be an issue since there will be no Progress vehicles to send off and incinerate into the Earth's atmosphere. Packaging materials will be used that have less mass but sufficient barrier properties for oxygen and water to maintain shelf life as those now in use.

• Korean Journal of Mineralogy and Petrology
• /
• v.34 no.1
• /
• pp.83-93
• /
• 2021

NASA has a plan for the Artemis manned lunar mission in 2020. In 2030s, not only America but also other countries are considering to prepare for human to stay on the Moon at least for a month and necessary technology is currently being developed. With this plan, the mostly considered thing is lunar in-situ resource utilization. The most essential resources could be water and oxygen for sustain human life on the Moon. These resources are not supposed to be brought from the Earth, and it is economically sensible if they are obtained from the lunar surface. Because oxygen can be used as both oxidizer and propellent when a rocket departs from a lunar base directly to Mars, technology for extraction method of oxygen resource and its utilization has been being developed worldwide. This paper introduces oxygen distribution on the Moon and major oxygen extraction methods.