• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.853-865
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• 2014

Hydrologic dam risk analysis depends on complex hydrologic analyses in that probabilistic relationship need to be established to quantify various uncertainties associated modeling process and inputs. However, the systematic approaches to uncertainty analysis for hydrologic risk analysis have not been addressed yet. In this paper, two major innovations are introduced to address this situation. The first is the use of a Hierarchical Bayesian model based regional frequency analysis to better convey uncertainties associated with the parameters of probability density function to the dam risk analysis. The second is the use of Bayesian model coupled HEC-1 rainfall-runoff model to estimate posterior distributions of the model parameters. A reservoir routing analysis with the existing operation rule was performed to convert the inflow scenarios into water surface level scenarios. Performance functions for dam risk model was finally employed to estimate hydrologic dam risk analysis. An application to the Dam in South Korea illustrates how the proposed approach can lead to potentially reliable estimates of dam safety, and an assessment of their sensitivity to the initial water surface level.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.65-70
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• 2006

From the beginning of the construction stage, the fire protection regulation for the nuclear power plants conforms to the design requirements for the acquisition of the license permit. This regulation is based on the plant status of the normal operation, but it is not enough to be used as an application standard for fire protection at the transient mode of the plant and the outage time for refueling as well as for the plant decommissioning. While the advanced fire protection requirement that has been developed in America recently suggests the performance-based requirement and management rule applicable to the overall life time of the plant, it simply represents the conceptual application. It means that it can not be treated as appropriate standards because it does not deal with the qualitative and quantitative approach in specific ways. By the way, with the use of the performance-based fire risk analysis, the dynamic behavior of the heat and smoke at the fire compartment of the nuclear power plants can be analyzed and the thermal effect to the safety-related equipment and cables can be evaluated as well. At this paper, it suggests the ways to change the applicable fire protection regulations and the required evaluation items for the fire risk resulted from the plant configuration change with an intent to introduce the state-of-the-art quantitative fire risk analysis technology at the domestic nuclear power plants.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.108-116
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• 2002

This paper presents the measurements and evaluation of voltage waveforms due to human electrostatic discharge(ESD). The principle of operation and design rule of a new device for measuring the ESD fast transient voltages with very fast rise time were described. Peak values and rise time of ESD voltages derived from a charged human body under a variety of experimental conditions were examined. The frequency bandwidth of the proposed voltage measuring system ranges from DC to 400[㎒]. The ESD voltage waveform is nearly equal to the ESD current waveform and the peak amplitude of ESD current waveform is roughly proportional to the ESD voltage in each experimental conditions. A rapid approach results in a discharge voltage with a faster initial rise time than for a slow approach. The voltages caused by direct finger ESDs have an initial slope with a relatively long, 10∼30[ns] rise time, but the amplitude is small. On the other hand, the voltages caused by direct hand/metal ESDs have a steep initial s1ope with 1 ∼3[ns] rise time, but an initial spike is very big. As a consequence, it was found that the ESD voltage and current waveforms strongly depend on the approach speed and material of intruder. These measurement results would be useful to design the ESD protective devices.