• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.73-79
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• 2002

Fretting wear test in room temperature air was performed to evaluate the wear mechanism of fuel rod using a fretting wear tester, which has been developed for experimental study. The main focus was to compare the wear behaviors of fuel rod against support springs at different contact geometries (i.e. concave and convex) and slip directions (axial and transverse). The wear on the tube was examined by the surface roughness tester, which measures the volume. The result indicated that with change of contact geometry from 5N of normal load to 0.1mm gap, wear volume of tube Increased in the condition of concave spring, but slowly decreased in convex spring. From the results of SEM observation, wear mechanism of each test condition was also depend on the above contact parameters. The wear mechanism of each test condition in room temperature air is discussed.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.1-9
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• 2016

The standard procedure of fire modeling was reviewed to minimize the user dependence, based on the NUREG-1934 and 1824 reports. The hazard analysis of lubricating oil fires in the air compressor room of domestic nuclear power plant (NPP) was also performed using a representative fire model, FDS (Fire Dynamics Simulator). The area ($A_f$) and location of fire source were considered as major parameters for the realistic fire scenarios. As a result, the maximum probability to exceed the thermal damage criteria of IEEE-383 unqualified electrical cables was predicted as approximately 70% with $A_f=1m^2$. It was also found that for qualified electrical cables, the maximum probabilities of exceeding the criteria were 2% and 90% with $A_f=2$ and $4m^2$, respectively. It was concluded that all electrical cables should be replaced with IEEE-383 qualified cables and the dike to restrict as $A_f{\leq}2m^2$ should be installed at the same time, in order to assure the thermal stability of electrical cables for lubricating oil fires in the air compressor room of domestic NPP.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.10-15
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• 2016

This paper is to analyze and study the failure examples of refrigerant gas in automotive air conditioner. The first example, the air conditioner compressor continually operated that the refrigerant was leaked in air conditioner system. By lubrication shortage, the piston was partially sticked on cylinder of air conditioner compressor inner part. This was caused the phenomenon of engine operation trouble by load increasing with engine rpm variation during engine running. The second example, it sought the fact that the air conditioner refrigerant gas was leaked from air conditioner compressor to condenser high pressure pipe toward rear air conditioner checking with the lines of air conditioner. The third example, the refrigerant gas of air conditioner found that was leaked imperceptible from condenser inner by crack that was generated on the fins of air conditioner condenser. Therefore, the air conditioner system that maintain the air conditioner by decreasing the in-car temperature must meticulously manage to not leak the air conditioner refrigerant gas.