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Hong S.J.,FNC Technology | Park G.C.,Seoul National University | Cho S.,Korea Atomic Energy Research Institute | Song C.-H.,Korea Atomic Energy Research Institute
International Journal of Multiphase Flow | Year: 2012

Condensation oscillation of submerged steam jet in water pool was investigated. From the experiments it was found that the dominant frequency of condensation oscillation was proportional to steam mass flux for steam mass flux under 300kg/m 2s and inversely proportional for over 300kg/m 2s. The frequency was always inversely proportional to pool temperature. For the high steam mass flux region (over 300kg/m 2s), one-dimensional mechanistic model was developed based on the balance of the kinetic energy that the steam jet gives and the pool water receives, adopting the submerged turbulent jet theory. The proposed model excellently predicted the dominant frequencies for the steam mass flux 300-900kg/m 2s and water temperature 35-75°C. For the higher water temperature, the developed model also could predict the dominant frequencies by adjusting the ratio of jet expansion coefficients of vapor dominant region and liquid dominant region. © 2011 Elsevier Ltd.


Yang Y.-H.,KHNP Central Research Institute | Lee G.-B.,KHNP Central Research Institute | Shon S.-H.,KHNP Central Research Institute | Kim J.-Y.,FNC Technology
Annals of Nuclear Energy | Year: 2015

The radiological environment around Wolsong NPP site has been monitored since Wolsong Unit 1 started commercial operation in 1983, as required by regulations in Korea. As a result of the periodic safety review on Wolsong Unit 3 & 4 in 2011, the regulator recommended that an assessment on the long-term accumulation trend of environmental radioactivity around Wolsong Unit 3 & 4 should be performed. In response to this, the assessment was performed based on environmental monitoring data and non-parametric statistical tool (i.e., Mann-Kendall Test). The environmental monitoring data included indicator organisms, soil and marine deposit which were usually monitored for verification of the typical radioactivity level. Most results of the assessment showed no trend and only a few results showed a slight increase. It was concluded that the radioactivity accumulation due to the operation of the plant was insignificant and thus no concern has been raised regarding any effect on the safety and health of the residents around Wolsong NPP site. It is expected that the result of this study could be utilized to establish the plan and policy for environmental monitoring at other NPP sites. © 2014 Elsevier Ltd. All rights reserved.


Provided is an apparatus for testing a loss-of-coolant accident using a model of a nuclear containment building, including a containment vessel of which an upper surface is opened and side and lower surfaces are transparent; an internal structure which is disposed in the containment vessel; a hose pipe which is disposed at an upper side of the containment vessel; and a measuring device which is disposed at the lower surface of the containment vessel so as to monitor movement of fluid and debris in the containment vessel.


Kim J.,FNC Technology | Jung H.,Korea Radioactive Waste Management Corporation | Ha J.-C.,Korea Radioactive Waste Management Corporation | Kim E.-H.,Seoul National University
Annals of Nuclear Energy | Year: 2013

In order to simulate gas migration at an underground disposal facility, the characteristics of a medium such as the gas threshold pressure and gas permeability need to be measured in advance. In this study, the gas threshold pressure and gas permeability of silo concrete specimens for a Korean LILW (Low- and Intermediate-Level Waste) disposal facility were measured. The concrete specimens had the same composition as the concrete used in the construction of the silo. The gas threshold pressure was measured by injecting a constant gas flow into cross sections of the specimens. To measure the gas permeability, selected pressures were applied to the specimens and the apparent permeability was calculated using the Hagen-Poiseuille equation. The intrinsic permeability was calculated with the Klinkenberg empirical equation. The gas threshold pressure and gas permeability ranged from 30 to 40 bar and from 10-17 to 10-18 m2, respectively. © 2012 Elsevier Ltd. All rights reserved.


Park J.B.,Korea Radioactive Waste Management Corporation | Kim C.-W.,Korea Hydro and Nuclear Power Co. | Kim S.-H.,FNC Technology | Kim J.Y.,FNC Technology
Annals of Nuclear Energy | Year: 2012

As part of the following-up action pertaining to the construction and operation permit for the first stage of the LILW (Low- and Intermediate-Level Radioactive Waste) repository, the preparation for a large-scale in situ experiment is underway by the Korea Radioactive Waste Management Corporation (KRMC) for a realistic assessment of the characteristics of gas generation after the post-closure phase of a repository. In this paper, we discuss a method of determining the representative composition of simulated dry active waste and a related fabrication plan for this material. After a comparison with experimental gas generation results from Finland, dry active waste content was chosen for a large-scale gas generation experiment. Six different types of materials and details on their simulated dry active waste contents are derived with the total mass and density for both a 200 L and a 320 L drum. © 2011 Elsevier Ltd. All rights reserved.

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