• Journal of Radiation Protection and Research
• /
• v.41 no.2
• /
• pp.155-159
• /
• 2016

Background: Nuclear reactors produce a great number of antielectron neutrinos mainly from beta-decay chains of fission products. Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may take part in special weak interactions. We calculate reactor antineutrino spectra especially in the low energy region. In this work we present neutrino spectrum from a typical pressurized water reactor (PWR) reactor core. Materials and Methods: To calculate neutrino spectra, we need information about all generated nuclides that emit neutrinos. They are mainly fission fragments, reaction products and trans-uranium nuclides that undergo negative beta decay. Information in relation to trans-uranium nuclide compositions and its evolution in time (burn-up process) were provided by a reactor code MVP-BURN. We used typical PWR parameter input for MVP-BURN code and assumed the reactor to be operated continuously for 1 year (12 months) in a steady thermal power (3.4 GWth). The PWR has three fuel compositions of 2.0, 3.5 and 4.1 wt% $^{235}U$ contents. For preliminary calculation we adopted a standard burn-up chain model provided by MVP-BURN. The chain model treated 21 heavy nuclides and 50 fission products. The MVB-BURN code utilized JENDL 3.3 as nuclear data library. Results and Discussion: We confirm that the antielectron neutrino flux in the low energy region increases with burn-up of nuclear fuel. The antielectron-neutrino spectrum in low energy region is influenced by beta emitter nuclides with low Q value in beta decay (e.g. $^{241}Pu$) which is influenced by burp-up level: Low energy antielectron-neutrino spectra or emission rates increase when beta emitters with low Q value in beta decay accumulate Conclusion: Our result shows the flux of low energy reactor neutrinos increases with burn-up of nuclear fuel.

• Journal of Radiation Protection and Research
• /
• v.41 no.4
• /
• pp.384-388
• /
• 2016

Background: For a verification of newly-developed neutron absorbers, one of guidelines on the qualification and acceptance of neutron absorbers is the neutron attenuation test. However, this approach can cause a problem for the qualifications that it cannot distinguish how the neutron attenuates from materials. Materials and Methods: In this study, an estimation method of neutron absorption performances for materials is proposed to detect both direct penetration and back-scattering neutrons. For the verification of the proposed method, MCNP simulations with the experimental system designed in this study were pursued using the polyethylene, iron, normal glass and the vitrified form. Results and Discussion: The results show that it can easily test neutron absorption ability using single absorber model. Also, from simulation results of single absorber and double absorbers model, it is verified that the proposed method can evaluate not only the direct thermal neutrons passing through materials, but also the scattered neutrons reflected to the materials. Therefore, the neutron absorption performances can be accurately estimated using the proposed method comparing with the conventional neutron attenuation test. Conclusion: It is expected that the proposed method can contribute to increase the reliability of the performance of neutron absorbers.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.46 no.5
• /
• pp.836-847
• /
• 2022

This study establishes basic data for the development of a new Chemical, Biological, and Radioactive (CBR) protective clothing by selecting the ventilation position to optimize thermal comfort on the basis of the opening and closing of each part. Participants were eight men in their 20s who had previously worn CBR protective clothing. After vigorous exercise and perspiration, the microclimate of the clothing and skin temperature was measured. Results revealed that when the ventilation zipper was opened after exercising, the skin and clothing microclimate temperatures, which had increased during the exercise, decreased in the chest and shoulder blade regions. The clothing microclimate humidity decreased in the chest area. The change was greatest in the chest region; the skin temperature decreased by 0.2℃, the clothing microclimate temperature by 2.7℃, and the clothing microclimate humidity by 3.2%RH through ventilation. Thus, the opening that allows the exchange of accumulated heat and moisture while wearing the CBR protective clothing is efficient.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.7
• /
• pp.877-882
• /
• 2014

The reduction of CO2 emission has been discussed in the Marine Environment Protection committee in the International Maritime Organization as the biggest causes of GHG for the purpose of indexing CO2 amounts released into the atmosphere from ships. Accordingly, various methods including the change in the hull design to improve energy efficiency, the coating development to reduce friction resistances, the additives development for improving thermal efficiency in an engine, the low-speed operation to reduce fuel consumptions, and etc. have been applied. The main engine of a ship is an electronic engine for improving the efficiency of the whole load area. However, marine generator engines still use mechanical drive engines in intake, exhaust, and fuel injection valve drive cams. In addition, most of marine generator engines in ships apply a part-load operation of less then 80% due to an overload protection system. Therefore, marine auxiliary diesel engine set at 100% load is necessary to readjust in order to efficient operation because of part-load operation. The objective of this study is to report the results of the part-load fuel consumption improvement by injection timing readjust to identifying the operational characteristics of a marine generator engine currently operated in a ship.

• Fire Science and Engineering
• /
• v.32 no.1
• /
• pp.89-98
• /
• 2018

Fire accidents in foreign countries, like the accident in a thermal power plant in Beijing, the accidents in domestic power plants, including Boryeong Power Plant in 2012 and Taean Power Plant in 2016, a disaster in a nuclear power plant in Fukushima in 2011 or the large-scale power failure in California in 2001 are safety accidents related to electric power, which caused losses in the people's stable lives and the countries. Electricity has an absolute impact on the people's life and the economy, so we can easily expect the serious situation affecting economic growth as well as direct damage to the protection of the people's lives and the losses of properties, if there are fire or explosion accidents or radioactive leak because of negligence in safety management, or problems because of natural disasters like an earthquake in power plants that generate electricity. In this study, it was drawn the improvement of the organizations exclusively in charge of firefighting, the operation of a program for the improvement of professional competency, the development of a customized firefighting management system for plants for systematic firefighting safety management and the improvement of the earthquake-proof correspondence system, which has recently become an issue, as measures for improvements through a survey of the actual conditions concerning the necessity of the construction of a firefighting safety management system for power plants with five power generation companies, including Korea Southern Power Co., Ltd., and the persons in charge of firefighting safety Korea Hydro & Nuclear Power Co., Ltd.

• Fire Science and Engineering
• /
• v.27 no.5
• /
• pp.15-18
• /
• 2013

This paper is concerned with the Performance and Reliability Certification for fire detection system in outdoor area such small and middle sized cultural assets, natural monument and outdoor facilities. Especially, if a fire were to occur in vulnerable area, it is difficulty to detect a fire. therefore we propose a high efficiency and low cost unmanned fire detection system in capable of an early detection regardless spontaneously fire or firebug. for Adoption of Intelligent Fire Detection System with movable and unmanned function breaking from the existing Conventional Fire Detection System, this Range of R&D includes the Performance test, Function test, Field test, Flame Detection test and EMI/EMS Compliance test. the Result data of Performance test, Function test and Field test is generally good during 3 months. also we checked that thermal variation test and EMI/EMS compliance test are good result data within allowable range. As a result of general test, we verified improvement results that the measure distance of fire detection extend 75 m, the Power of waiting time increase 4 hours, the Power of operation time increase 3 days and the context awareness with video as well as sensors.

• Steel and Composite Structures
• /
• v.37 no.5
• /
• pp.589-603
• /
• 2020

This paper presents an investigation of the thermal performance of composite floor slabs with profiled steel decking exposed to fire effects from floor. A detailed finite-element model has been developed by representing the concrete slab with steel decking under of it and steel beam both steel parts protected by intumescent coating. Although this type of floor systems offers a better fire resistance, passive fire protection materials should be applied when a higher fire resistance is desired. Moreover, fire exposed side is so crucial for composite slab systems as the total fire behaviour of the floor system changes dramatically. When the fire attack from steel parts, the temperature rises rapidly resulting in a sudden decrease on the strength of the beam and decking. Herein this paper, the fire attack side is assumed from the face of the concrete floor (top of the concrete assembly). Therefore, the heat is transferred through concrete to the steel decking and reaching finally to the steel beam both protected by intumescent coating. In this work, the numerical model has been established to predict the heat transfer performance including material properties such as thermal conductivity, specific heat and dry film thickness of intumescent coating. The developed numerical model has been divided into different layers to understand the sensitivity of steel temperature to the number of layers of intumescent coating. Results show that the protected composite floors offer a higher fire resistance as the temperature of the steel section remains below 60℃ even after 60-minute Standard (ISO) fire and Fast fire exposure. Obtaining lower temperatures in steel due to the great fire performance of the concrete itself results in lesser reductions of strength and stiffness hence, lesser deflections.

• Informatization Policy
• /
• v.25 no.2
• /
• pp.3-19
• /
• 2018

With the introduction of video cameras into law enforcement, a great deal of police organizations have adopted the technology in their routine crime prevention activities. The up-to-date systems of ambient surveillance energized by CCTV, police wearable cameras, drones, and thermal imaging devices enable the police to thoroughly monitor public spaces as well as to rigorously arrest on-scene criminals. These efforts to improve the level of surveillance are often met with public resistance raising concerns over citizens' rights to privacy. Recent studies on the use of police video equipment have constantly raised the issues related to the lack of applicable legal provisions, risk of personal information and privacy infringement as well as security vulnerabilities. In this regard, the present study attempted to review the public surveillance methods currently used by law enforcement agencies worldwide within the context of public safety and individual rights to privacy. Furthermore, the present study also discussed the legal boundaries of police use of video equipment to address public concerns over privacy issues.

• Journal of the Korean Electrochemical Society
• /
• v.4 no.4
• /
• pp.152-159
• /
• 2001

Electric vehicle performance is very dependent on traction batteries. For developing the electric vehicles with high performance and good reliability, the traction batteries have to be managed to get maximum performance under various operating conditions. The enhancement of the battery performance can be accomplished by implementing battery management system (BMS) that plays important roles of optimizing the control mechanism of charge and discharge of the batteries as well as monitoring battery status. In this study the battery management system has been developed for maximizing the use of Ni/MH batteries in electric vehicle. This system provides several tasks: the control of charging and discharging, overcharge and over-discharge protection, the calculation and display of state of charge, safety and thermal management. The BMS was installed in and tested using the DEV5-5 electric vehicle developed by Daewoo Motor Co. and Institute for Advanced Engineering in Korea. The 18 modules of Panasonic Ni/MH battery, 12 V-95 Ah, were used in the DEV5-5. The high accuracy within the range of $3\%$ and the good reliability were shown in the test results. The BMS can also improve the performance and cycle life of Ni/MH battery pack as well as the reliability and safety of the electric vehicles (EV).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.6
• /
• pp.1128-1133
• /
• 2011

In a wind farm, a large number of small wind turbine generators (WTGs) operate whilst a small number of a large generator do in a conventional power plant. To maintain high quality and reliability of electrical energy, a wind farm should have equal performance to a thermal power plant in the transient state as well as in the steady state. The wind farm shows similar performance to the conventional power plant in the steady state due to the advanced control technologies. However, it shows quite different characteristics during fault conditions in a grid, which gives significant effects on the operation of a wind farm and the power system stability. This paper presents an analysis of response of a wind farm during grid fault conditions. During fault conditions, each WTG might produce different frequency components in the voltage. The different frequency components result in the non-fundamental frequencies in the voltage and the current of a wind farm, which is called by "beats". This phenomenon requires considerable changes of control technologies of a WTG to improve the characteristics in the transient state such as a fault ride-through requirement of a wind farm. Moreover, it may cause difficulties in protection relays of a wind farm. This paper analyzes the response of a wind farm for various fault conditions using a PSCAD/EMTDC simulator.