• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.577-585
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• 2009

A 9-node degenerated shell finite element(FE), which has been developed for assessment of ultimate pressure capacity and nonlinear analysis for nuclear containment building is described in this paper. Reissner-Midnlin(RM) assumptions are adopted to develop the shell FE so that transverse shear deformation effects is considered. Material model for concrete prior to cracking is constructed based on the equivalent stress-equivalent strain relationship. Tension stiffening model, shear transfer mechanism and compressive strength reduction model are used to model the material behavior of concrete after cracking. Niwa and Aoyagi-Yamada failure criteria have been adapted to find initial cracking point in compression-tension and tension-tension region, respectively. Finally, the performance of the developed program is tested and demonstrated with several examples. From the numerical tests, the present results show a good agreement with experimental data or other numerical results.

• Particle and aerosol research
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• v.10 no.4
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• pp.137-154
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• 2014

Prediction of the behavior of radioactive aerosol particles in a containment is of importance for the assessment of the consequences of nuclear power plant severe accidents because most radioactive air pollutants are emitted as aerosol particles upon severe accident. The performance of engineering safety features (ESFs) is also influenced by the characteristics of the aerosol particles. In this article, the characteristics of aerosol particles in reactor containments reported by previous studies were reviewed. The results of the experiments for postulated accidents in test reactors, for aerosol behavior analysis using artificial test aerosols, and for ESF performance evaluation were summarized. The summary of this article will be of use in designing and performance-evaluating ESFs.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.795-801
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• 2021

The designed drone-based unmanned remote radiation detection module was developed according to the needs of the nuclear power plant decommissioning workshop. Using the Geiger-Mueller tube sensitive to low-level radiation measurement, It was manufactured to measure the amount of radiation leaking into and out of the containment vessel. The drone-based radiation detection module weighs less than 200g, It can be operated inside and outside the containment vessel of a nuclear power plant. To check the performance of the designed equipment, a performance evaluation test was conducted with reference to the international standard (IEC-60864). The stability of the radiation detection module designed to meet the needs of the field the statistical rate of change by repeated measurements in the rate of change experiment to evaluate the measurement accuracy was ±4.6%. The accuracy ±7.3% in the linearity experiment to evaluate the dose rate dependence, the linear The figure satisfies the international performance evaluation standard of ±3.5%. The radiation detection module developed in this study is a customized equipment for a nuclear power plant dismantling workshop. It will be helpful for accurate measurement of space dose rate and safety management of radiation worksites in sites with a lot of radiation dust.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.27-35
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• 2018

The passive containment cooling system (PCCS) has been designed to remove the released decay heat during the accident by means of the condensation heat transfer phenomenon to guarantee the safety of the nuclear power plant. The heat removal performance of the PCCS is mainly governed by the condensation heat transfer of the steam-air mixture. In this study, the heat removal performance of the PCCS was evaluated by using the MARS-KS code with a new empirical correlation for steam condensation in the presence of a noncondensable gas. A new empirical correlation implemented into the MARS-KS code was developed as a function of parameters that affect the condensation heat transfer coefficient, such as the pressure, the wall subcooling, the noncondensable gas mass fraction and the aspect ratio of the condenser tube. The empirical correlation was applied to the MARS-KS code to replace the default Colburn-Hougen model. The various thermal-hydraulic parameters during the operation of the PCCS follonwing a large-break loss-of-coolant-accident were analyzed. The transient pressure behavior inside the containment from the MARS-KS with the empirical correlation was compared with calculated with the Colburn-Hougen model.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.41-41
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• 2003

Transgenic triploid hybrid between fast-growingtransgenic mud loach (Misgurnus mizolepis) males and cyprinid loach (M. anguillicaudatus) females were generated and their performance on growth, feed conversion ability and reproduction were evaluated. Although the growth accelerations of diploid and triploid transgenic hybrids were not as much as those of original transgenic mud loaches, they still represented persistent growth stimulation ranging 11 to 28 fold when compared to their non-transgenic counterparts, with significantly improved feed conversion efficiency up to 2-fold (compared to non-transgenic hybrid) and 1.5-fold (compared to non-transgenic mud loach) in maximum. The gonad development of diploid hybrids was fertile in histological views regardless of transgenic genotypes but the extent of developmentin hybrid fish were less than mud loach diploids at the same age. On the other hands, very stringent sterility was obtained in both sexes of the triploid hybrid transgenics: ovary and testis from transgenic triploid hybrids were significantly depressed and any notable sign for maturation to ovum or spermatids was not detected. No viable embryo was obtained in a fertilization trial using the suspension prepared from the minced testes of transgenic triploid hybrids. This study may indicate the potential usefulness of triploid hybridization as a mean for reproductive containment of transgenic mud loach.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.307-322
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• 2014

With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO). The global Floating LNG (FLNG) market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1450-1455
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• 2009

Assumed that an IPTV camera system is to be used as an ad-hoc sensor for the surveillance and diagnostics of safety-critical equipments installed in the in-containment building of the nuclear power plant, an major problem is the presence of high dose-rate gamma irradiation fields inside the one. In order to uses an IPTV camera in such intense gamma radiation environment of the in-containment building, the radiation-weakened devices including a CCD imaging sensor, FPGA, ASIC and microprocessors are to be properly shielded from high dose-rate gamma radiation using the high-density material, lead or tungsten. But the passive elements such as mirror, lens and window, which are placed in the optical path of the CCD imaging sensor, are exposed to a high dose-rate gamma ray source directly. So, the gamma-ray irradiation characteristics of the passive elements, is needed to test. A CCD camera lens, made of glass material, have been gamma irradiated at the dose rate of 4.2 kGy/h during an hour up to a total dose of 4 kGy. The radiation induced color-center in the glass lens is observed. The degradation performance of the gamma irradiated lens is explained using an color component analysis.

• Journal of the Korean Society for Marine Environment & Energy
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• v.2 no.1
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• pp.49-62
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• 1999

The main functions of oil booms are to prevent spreading of the oil slick and to increase the recovering efficiency of oil skimmers. The oil-containment capability of a floating boom on an open sea is affected by environmental parameters such as waves, currents and winds, as well as the motion characteristics of a boom section. In this study, a series of tests were conducted for three kinds of booms (internal foam type, air inflatable type, self-expanded type) at the open sea off Yosu, and the results are presented. Motion characteristics and oversplashing phenomenon were observed for each boom in different environmental conditions. And the tension exerted on towing line of the boom was also measured with a systematic varitation of towing speeds and gap ratios.

• Earthquakes and Structures
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• v.15 no.3
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• pp.295-306
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• 2018

Reinforced concrete containment (RCC) building has long been considered as the last barrier for keeping the radiation from leaking into the environment. It is important to quantify the performance of these structures and facilities considering extreme conditions. However, the preceding research on evaluating nuclear power plant (NPP) structures, particularly considering mainshock-aftershock seismic sequences, is deficient. Therefore, this manuscript serves to investigate the seismic fragility of a typical RCC building subjected to mainshock-aftershock seismic sequences. The implementation of the fragility assessment has been performed based on the incremental dynamic analysis (IDA) method. A lumped mass RCC model considering the tri-linear skeleton curve and the maximum point-oriented hysteretic rule is employed for IDA analyses. The results indicate that the seismic capacity of the RCC building would be overestimated without taking into account the mainshock-aftershock effects. It is also found that the seismic capacity of the RCC building decreases with the increase of the relative intensity of aftershock ground motions to mainshock ground motions. In addition, the effects of artificial mainshock-aftershock ground motions generated from the repeated and randomized approaches and the polarity of the aftershock with respect to the mainshock on the evaluation of the RCC are also researched, respectively.

• Nuclear Engineering and Technology
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• v.30 no.1
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• pp.58-74
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• 1998

A PC window-based computer code, CONPAS (CONtainment Performance Analysis System), has been developed to integrate the numerical, graphical, and results-operation aspects of Level 2 probabilistic safety assessments (PSA) for nuclear power plants automatically. As a main logic for accident progression analysis, it employs a concept of the small containment phenomenological event tree (CPET) helpful to trace out visually individual accident progressions and of the detailed supporting event tree (DSET) for its detailed quantification. For the integrated analysis of Level 2 PSA, the code utilizes five distinct, but closely related modules. Its computational feasibility to real PSAs has been assessed through an application to the UCN 3&4 full scope Level 2 PSA. Compared with other existing computer codes for Level 2 PSA, the CONPAS code provides several advanced features: (1) systematic uncertainty analysis / importance analysis / sensitivity analysis, (2) table / graphical display & print, (3) employment of the recent Level 2 PSA technologies, and (4) highly effective user interface. The main purpose of this paper is to introduce the key features of CONPAS code and results of its feasibility study.