• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.61-66
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• 1984

A study on the characteristics of ${\alpha}$-particle track on cellulose nitrate film was carried out with a particular emphasis on the dependence of track diameter upon chemical etching condition. The track diameters etched in KOH solution appeared to be, on average, three times larger than those etched in NaOH under the same etching condition. The relationship between the track diameters and both etching time and the energy of incident ${\alpha}$-particles was also investigated. It is shown that the particle fluence rate is fairly independent of etching time as far as the condition of irradiation remains unchanged.

• Journal of Radiation Protection and Research
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• v.37 no.2
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• pp.70-74
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• 2012

Silicon carbide (SiC) is a promising material for neutron detection at harsh environments because of its capability to withstand strong radiation fields and high temperatures. Two PIN-type SiC semiconductor neutron detectors, which can be used for nuclear power plant (NPP) applications, such as in-core reactor neutron flux monitoring and measurement, were designed and fabricated. As a preliminary test, MCNPX simulations were performed to estimate reaction probabilities with respect to neutron energies. In the experiment, I-V curves were measured to confirm the diode characteristic of the detectors, and pulse height spectra were measured for neutron responses by using a $^{252}Cf$ neutron source at KRISS (Korea Research Institute of Standards and Science), and a Tandem accelerator at KIGAM (Korea Institute of Geoscience and Mineral Resources). The neutron counts of the detector were linearly increased as the incident neutron flux got larger.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.476-486
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• 2004

This paper is the second part of the study on the development of a smart active layer (SAL) sensor, which consists of two parts. As mentioned in the first paper, structural health monitoring (SHM) is a new technology that is being increasingly applied at the industrial field as a potential approach to improve cost and convenience of structural inspection. Recently, the development of smart sensor is very active for real application. This study has focused on preparation and application study of SAL sensor which is described with regard to the theory and concept of the SAL sensor in the first paper. In order to detect elastic wave, smart piezoelectric sensor, SAL, is fabricated by using a piezoelectric element, shielding layer and protection layer. This protection layer plays an important role in a patched network of distributed piezoelectric sensor and shielding treatment. Four types of SAL sensor are designed/prepared/tested, and these details will be discussed in the paper In this study, SAL sensor ran be feasibly applied to perform structural health monitoring and to detect damage sources which result in elastic waves.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.5
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• pp.500-508
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• 2014

In the ongoing debates over the need to identify new sources of energy and to reduce the emissions of greenhouse gases. Hydrogen has emerged as one of the most promising alternatives due to its emissions from the vehicle being virtually zero. The governments have identified the development of regulations and standards as one of the key requirements for commercialization of HFCV. Regulations and standards will help overcome technological barriers to commercialization. The development of Global Technical Regulation (GTR) for HFCV occurred under the World Forum for Harmonization of Vehicle Regulations. Development of a technique for safety assessment of HFCV include four tasks, research for regulation system and policy, hydrogen safety, vehicle operation safety and protection against high-voltage. The objective is to establish a technique for safety assessment and amend safety standards for HFCV and consequently reflect research results to vehicle management policy. We devised safety standards and evaluation techniques with regard to high-pressure gas and high voltage of hydrogen fuel cell vehicle. KMVSS for HFCV was amended to June 10, 2014. including the results of the safety assessment technology for high-voltage and hydrogen characteristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.437-443
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• 2014

Electric motors and drives consume the largest amount of electricity more than 40% of global electricity consumption. In addition, motors, drives and its components are included in the global high-trade products and the main driving source for industrial equipment and house appliances. Thus, International standards and regulations for their safety and efficiency are internationally being discussed and created for the protection of its citizens and energy saving. So, understanding the international standards and the regulation of each country is essential to enhance overseas market and to develop product. In this paper, on the basis of this background, status and trends of international standards and regulations are introduced for safety and efficiency of motors and the drives. Safety and efficiency of the IEC (International Electrotechical Commission) standards are introduced in the emphasis. Also, regulations are studied about the differences and trends in each county.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.81-87
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• 2013

A grounding scheme is one of important parts in protection for safety of electrical installations. Terminologies are successively creating and gradually increasing due to diversity and external environments. The declaration and definition of terminologies concerning grounding are in disorder in several KS standards, electrotechnical provisions for electrical installations and electrotechnical guides related to electrical installations. There seem to be serious confusions in use among technicians and experts. In this paper, we proposed a new scheme and system to consistently use the technical terms concerning grounding described in KS standards and technical provisions. Different use examples and the present state of terminologies on grounding described in Korean documents such as KS IEC standards, technical provisions for electrical installations, consumer's electrical installation guide, and etc are investigated. Although the scope of this work is limited to examine the terminologies on grounding, it is expected that the proposed method could be contributed to the consistent use of terminologies in all areas in KS C IEC standards and technical provisions for electrical installations.

• Journal of Radiation Protection and Research
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• v.10 no.1
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• pp.14-28
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• 1985

The development of mono energetic photon sources using $K_{\alpha}$ fluorescence X-ray of pure material was carried out in the energy range below 100 keV. The monoenergetic photons are very useful in the calibration of the radiation measuring instruments and can be produced as the $K_{\alpha}$ fluorescence X-ray by irradiating the bremsstrahlung to the thin pure metal foils called ‘radiators’. In this experiment, several radiators such as $_{47}Ag,\;_{50}Sn,\;_{68}Er,\;_{70}Yb,\;and\;_{82}Pb$ provide the wide monoenergetic photon energy ranging from 20 keV to 80 keV. By the spectrometry with HpGe LEPS, spectral purity factors which measure the monochrometicity for the $K_{\alpha}$ fluorescence X-ray, were determined as $0.64{\sim}0.94$. Dosimetry for the purpose of the determination of the exposure rate with a 600cc thin window ionization chamber, which was calibrated by the standard free-air ionization chamber, was performed. Exposure rates ranging $8.3{\sim}232.5mR/h$ was obtained according to the $K_{\alpha}$ fluorescence X-ray energy for each radiator.

• Fire Science and Engineering
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• v.30 no.2
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• pp.43-48
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• 2016

One of the main problems with gaseous fire extinguishers is the decrease in fire suppression capability due to the leakage of the fire extinguishing agents, either naturally or caused by obsolete equipment. Therefore, in this study, a real-time detector module for monitoring pressure leakages was developed and an assessment on its performance was carried out. Currently, there are no domestic or global standards for testing pressure leakage detection systems. Therefore, similar global standards, such as ISO 7240 and FM 1421, and the domestic law on "Receiver type-approval and technical standards for product inspection" were used as a reference for assessing the performance of the newly developed module. Its basic performance was assessed by applying compressed air to the module, and, as a result, the minimum working pressure was identified as 0.3 bar. Its environmental qualification was carried out to confirm the proper functioning of the module in different climates and the module was confirmed to function properly at both high ($50^{\circ}C$) and low ($-10^{\circ}C$) temperatures.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.384-388
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• 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 Radiation Protection and Research
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• v.10 no.2
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• pp.113-121
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• 1985

For the safety assessment of radwaste treatment and disposal, the leaching characteristics of $Cs^+\;and\;Sr^{++}$ from the cement-solidified radwastes was investigated by means of the survey and analysis of the activity leach rate and cumulative leach fraction of $^{137}Cs\;and\;^{90}Sr$ leaching from solidified radwastes. The cylindrical cement-solidified samples were made by the sodium silicate method and neutralization method changing the mole density of simulated liquid radwaste, type of cement, adding material and concentration of boric acid. The leaching study was carried out by the method using simulated PWR concentrated liquid radwaste solidified in cement that had been processed following the recommendations of IAEA. All the experimental results are in well accordance with the research data reported previously, but the watertight cement-solidified radwastes show rather high leach rate of radioactivity. It is learned, therefore, that the watertight cement is not adequate as the material for the solidified radwastes.