• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.10
• /
• pp.1093-1100
• /
• 2014

The purpose of this paper is to suggest a weight-reduction design method for the hybrid carbody of a high-speed maglev train that uses aluminum extrusion profiles and sandwich composites. A sandwich composite was used on the roof as a secondary member to minimize the weight. In order to assemble the sandwich composite roof and aluminum extrusion side frame of the carbody using welding, a guide aluminum frame located at the four sides of the sandwich composite roof was introduced in this study. The clamping force of this guide aluminum frame was verified by three-point bending test. The structural integrity and crashworthiness of the hybrid carbody of a high-speed maglev train were evaluated and verified according to the Korean Railway Safety Law using a commercial finite element analysis program. The results showed that the hybrid carbody composed of aluminum extrusion frames and a sandwich composite roof was lighter in weight than a carbody made only of aluminum extrusion profiles and had better structural performance.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.4
• /
• pp.374-382
• /
• 2009

Steam generator(SG) tube, as a barrier isolating primary to the secondary coolant system of nuclear power plants(NPP), must maintain the structural integrity far the public safety and its efficient power generation capacity. And SG tubes bearing defects must be timely detected and taken repair measures if needed. For the accomplishment of these objectives, SG tubes have been periodically examined by eddy current testing(ECT) on the basis of administrative notices and intensified SG management program(SGMP). Stress corrosion cracking(SCC) on the SG tubes is not easily detected and even missed since it has lower signal amplitude and other disturbing factors against its detection. However once SCC is developed, that can cause detrimental affects to the SG tubes due to its rapid propagation rate. Accordingly SCC is categorized as prime damage mechanism challenging the soundness of the SG tubes. In this study, reproduced EDM notch specimens are examined for the detectability and quantitative characterization of the axial ODSCC by +PT MRPC probe, containing pancake, +PT and shielded pancake coils apart in a single plane around the circumference. The results of this study are assumed to be applicable fur providing key information of engineering evaluation of SCC and improvement of confidence level of ECT on SG tubes.

• The Journal of Engineering Geology
• /
• v.20 no.4
• /
• pp.359-370
• /
• 2010

$CO_2$ leakage from a geological formation utilized for $CO_2$ storage could result in failure of the facility and threaten the environment, as well as human safety and health. A reactive transport model of a $CO_2-H_2O$-cement reaction was constructed to understand chemical changes in the case of $CO_2$ leakage through a cement crack in an injection well, which is the most probable leakage pathway during geological storage. The model results showed the dissolution of portlandite and CSH (calcium silicate hydrate) within the cement paste, and the precipitation of secondary CSH and calcite as the $CO_2$ plume migrated along the crack. Calcite occupied most of the crack after 3 year of reaction, which could be maintained until 30 years after crack development. The present results could be applied in the development of technology to prevent $CO_2$ leakage and to enhance the integrity of wells constructed for $CO_2$ geological storage.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.11a
• /
• pp.126-133
• /
• 2005

Securing of radioactive waste disposal site and the related operations for disposal of low and intermediate level radioactive waste is being actively carried out in Korea. For disposal of radioactive wastes, physicochemical and radiological status and integrity of radioactive wastes must be secured first. Also, waste generators must provide this information to disposers. In addition, to secure the safety of waste disposal, waste acceptance criteria (WAC) and site specific waste acceptance criteria (SWAC) to consider characteristics of the disposal site are required. Radioactive wastes must be processed, generated, managed and transferred in accordance with these criteria. [1] For this, evaluation of properties on each of the radioactive wastes must be performed. However, in reality, atomic power plants are experiencing difficulties in relation to this due to the large quantity of radioactive waste generation. In order to solve this problem, IAEA and major overseas countries have developed, thus are using waste certification program (WCP) and quality assurance program (QAP) [2,3]. On the basis of these programs, radioactive waste certification program has been developed for safe disposal of radioactive wastes in Korea to satisfy the provisions specified in 'low and intermediate level radioactive waste transfer guidelines' of announcement No. 2005-18 from the Ministry of Science and Technology and specific site waste acceptance criteria (tentative plan). In addition, it is being planned to administer amendment on commercial atomic power plant related procedures and ensile staff training in order for early introduction and operation of radioactive waste certification system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.15 no.4
• /
• pp.391-402
• /
• 2017

The Korea Radioactive Waste Agency (KORAD) has developed a concrete cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. During long-term storage of spent nuclear fuel in concrete casks kept in dry conditions, the integrity of the concrete cask and spent nuclear fuel must be maintained. In addition, the radiation dose rate must not exceed the storage facility's design standards. A suitable shielding design for radiation protection must be in place for the dry storage facilities of spent nuclear fuel under normal and accident conditions. Evaluation results show that the appropriate distance to the annual dose rate of 0.25 mSv for ordinary citizens is approximately 230 m. For a $2{\times}10$ arrangement within storage facilities, rollover accidents are assumed to have occurred while transferring one additional storage cask, with the bottom of the cask facing the controlled area boundary. The dose rates of 12.81 and 1.28 mSv were calculated at 100 m and 230 m from the outermost cask in the $2{\times}10$ arrangement. Therefore, a spent nuclear fuel concrete cask and storage facilities maintain radiological safety if the distance to the appropriately assessed controlled area boundary is ensured. In the future, the results of this study will be useful for the design and operation of nuclear power plant on-site storage or intermediate storage facilities based on the spent fuel management strategy.

• Journal of Home Health Care Nursing
• /
• v.8 no.2
• /
• pp.121-134
• /
• 2001

The purpose of this study were to analyze the home care services and to evaluate the client's satisfaction with the home care services provided by home care service center in the C hospital. The data were collected by reviewing charts of 128 home care clients who were receiving home care services at C hospital from October 1997 to September 2000. The subjects for satisfaction of home care service were 20 clients from July 10 to September 30, 2000. The tool for measurement of present condition of home care service was developed by the researchers. The satisfactions of the home care services were measured by using the instrument developed by Im(997). The data were analyzed by using the SPSS/PC+. The results of this study were as followings : 1. Majority of the subjects was female(61.7%). The average of age was 63.5 years. The service has been used mostly by the elderly 60 years of age or older(71.1%). The economic level of most of subjects was in middle class(94.5%). 2. Majority of the subject had a cancer(55.4%), following stroke(25.0%). The average duration of disease for the subjects was 31 months. The average time of hospitalization for the subjects was 3.3 times. The duration of hospitalization was 10$\sim$30 days(26.6%), 30$\sim$60 days(23.4%) and above of the 210 days(9.4%). 3. Most of the subjects used his/her doctor (47.7%), as a consultant, following his/her nurse (28.1%), other patients or their family (21.9%). Most of reasons for a consultation were supportive management(Infusion or medication, 60.94%), following tube management(L-tube or T-tube, 25%), Foley catheter management (15.63%) etc. 4. 28 types of nursing diagnoses were used by the home care service. The nursing diagnosis altered nutrition: less than body requirement were used mostly by the home care service, following risk for infection, impaired skin integrity, impaired swallowing, ineffective airway clearance altered comfort: pain, impaired physical mobility. By the human-response pattern, exchanging(63.2%), moving(7.5%), feeling(10.4%), knowing(5.2%), communicating (2.6%), relating(0.5%) perceiving(0.4%) and choosing(0.3%). There were 42 nursing intervention types were performed by the home care service. By the NIC(nursing intervention classification. McCloskey. Bulech. 1996). physiologic: complex (30.3%) was the most, safety(28.3%), behavioral(20.0%), physiologic: basic(10.8%) and health system(1.7%). Observation or assessment was the most nursing intervention performed by the home care service. following IV infusion. vital sign observation. infusion management and fluid-electrolyte balance management. 5. The level of client's satisfaction with provided home care services showed considerably high(2.67/ 3).

• Journal of Radiation Protection and Research
• /
• v.32 no.1
• /
• pp.35-44
• /
• 2007

Sealed sources have to conducted the tests be done according to the classification requirements for their typical usages in accordance with the relevant domestic notice standard and ISO 2919. After each test, the source shall be examined visually for loss of integrity and pass an appropriate leakage test. Tests to class a sealed source are temperature, external pressure, impact, vibration and puncture test. The environmental test conditions for tests with class numbers are arranged in increasing order of severity. In this study, the apparatus of tests, except the vibration test, were developed and applied to three kinds of sealed source. The conditions of the tests to class a sealed source were stated and the difference between the domestic notice standard and ISO 2919 were considered. And apparatus of the tests were made. Using developed apparatus we conducted the tests for $^{192}Ir$ brachytherapy sealed source and two kinds of sealed source for industrial radiography. $^{192}Ir$ brachytherapy sealed source is classified by temperature class 5, external pressure class 3, impact class 2 and vibration and puncture class 1. Two kinds of sealed source for industrial radiography are classified by temperature class 4, external pressure class 2, impact and puncture class 5 and vibration class 1. After the tests, Liquid nitrogen bubble test and vacuum bubble test were done to evaluate the safety of the sealed sources.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.1105-1111
• /
• 2010

The Korea Atomic Energy Research Institutes has been developing the SMART (System integrated Modular Advanced ReacTor), an environment-friendly nuclear reactor for the generation of electricity and to perform desalination. SMART reactors can be exposed to various external and internal loads caused by seismic and coolant flows. The CRDM(control rod drive mechanism), one of structures of the SMART, is a component which is adjusting inserting amount of a control rod, controlling output of reactor power and in an emergency situation, inserting a control rod to stop the reactor. The purpose of this research is performing the analysis of dynamic characteristic to ensure safety and integrity of structure of CRDM. This paper presents two FE-models, 3-D solid model and simplified Beam model of the CRDM in the coolant, and then compared the results of the dynamic characteristic about the two FE-models using a commercial Finite Element tool, ABAQUS CAE V6.8 and ANSYS V12. Beam 4 and beam 188 of simplified-model were also compared each other. And simplified model is updated for accuracy compare to 3-D solid.

• Journal of Korean Society of Forest Science
• /
• v.95 no.1
• /
• pp.73-81
• /
• 2006

This study has the object of deriving schemes for not only securing safety of chestnuts, which is the most important forest product in terms of both production and exportation, to consumers with implementing persistent production of them in harmony with the environment, but also producing environmentally friendly chestnuts that can contribute to the increase of a farm household's income through price differentiation from other chestnuts, which are grown by generally accepted ways. In order to do this, I performed an analysis of the reality and outcome from the management of farm households that produce environmentally friendly chestnuts. The result of the analysis demonstrated some problems such as poor establishment of farming skills in a beginning stage, administrative problems with weeding operations and prevention of blight, difficulty in ensuring distribution channels and high production cost. Therefore, propelling productive expansion of environmentally friendly chestnuts after resolving these problems requires many supports and ideas: establishment and diffusion of farming skill system under the cooperation of civil and government organizations, construction of environmentally friendly INM (Integrated Nutrient Management) and IPM (Integrated Pest Management), creation of production areas for improving productivity, introduction of 'Institution of Income Conservation for Environmentally-Friendly Production' that can help farmers to preserve integrity of income on their switchover to production of environmentally friendly chestnuts from generally-grown chestnuts, and finally strong and persistent promotion of environmentally friendly chestnuts towards existing farmers and consumers.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.3
• /
• pp.23-30
• /
• 2003

In this study, the various load cases by specified by the IEC61400-1 international specification and GL Regulations for the wind energy conversion system were considered, and a specific composite structure configuration which can effectively endure various loads was proposed. In order to evaluate the structure, the structural analysis for the composite wind turbine blade was performed using the finite element method(FEM). In the structural design, the acceptable configuration of blade structure was determined through the parametric studies, and the most dominant design parameters were confirmed. In the stress analysis using the FEM, it was confirmed that the blade structure was safe and stable for all the considerd load cases. Moreover the safety of the blade root joint with insert bolts, newly devised in this study, was checked against the design loads and also the fatigue loads. The fatigue life for operating more than 20 years was estimated by using the well-known S-N linear damage rule, the load spectrum and Spera's empirical equations. The full-scale static test was performed under the simulated aerodynamic loads. from the experimental results, it was found that the designed blade had the structural integrity. Furthermore the measured results were agreed with the analytical results such as deflections, strains, the mass and the radial center of gravity. The studied blade was successfully certified by an international institute, GL, of Germany.