• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.762-769
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• 2024

The TMSR-SF0 simulator is an integral effect thermal-hydraulic experimental system for the development of thorium molten salt reactor (TMSR) program in China. The simulator has two heat transport loops with liquid FLiNaK. In literature, the 95% level confidence uncertainties of the thermophysical properties of FLiNaK are recommended, and the uncertainties of density, heat capacity, thermal conductivity and viscosity are ±2%, ±10, ±10% and ±10% respectively. In order to investigate the effects of thermophysical properties uncertainties on the molten salt heat transport system, the uncertainty and sensitivity analysis of the heat transfer characteristics of the simulator system are carried out on a RELAP5 model. The uncertainties of thermophysical properties are incorporated in simulation model and the Monte Carlo sampling method is used to propagate the input uncertainties through the model. The simulation results indicate that the uncertainty propagated to core outlet temperature is about ±10 ℃ with a confidence level of 95% in a steady-state operation condition. The result should be noted in the design, operation and code validation of molten salt reactor. In addition, more experimental data is necessary for quantifying the uncertainty of thermophysical properties of molten salts.

• Elastomers and Composites
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• v.55 no.4
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• pp.249-256
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• 2020

Superabsorbent polymers (SAPs) can absorb and retain ten to thousand times their dry mass of water because of their three-dimensional hydrophilic structures. Conventional SAPs are mainly composed of poly(acrylic acid sodium salt) derived from petrochemicals. The present work is aimed at limiting the use of the petrochemical component by replacing it with a biomass-based material. First, the core-SAP was prepared via the terpolymerization of itaconic acid, vinylsulfonic acid, and cellulose, and the optimum conditions in terms of material input ratio were determined. Following this, the core-SAP was surface-crosslinked by esterification with butane diol to improve its liquid permeability and absorbency under load (AUL). The liquid permeability was measured according to the amount of 0.9 wt.% NaCl solution passing between the swollen SAP particles under a given pressure, and the AUL was estimated from the weight of this solution absorbed under 0.3 psi pressure.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.189-189
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• 2005

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.191-191
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• 2005

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.113-118
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• 1999

AMBIDEXTER(Advanced Molten-salt Break-even Inherently-safe Dual-mission Experimental and TEst Reactor)는 고온저압의 Th/$^{233}$ U 불화용융염을 핵연료로 사용하므로 피복관이나 독립된 냉각재 없이 핵연료 자체가 열수송 매체로서 순환하는 원자로시스템개념으로서 저농축 $^{235}$ U 고체 핵연료를 사용하는 기존의 원자력 발전시스템이 안고있는 핵확산과 안전성 등의 고유문제를 해결할 수 있는 혁신형 차세대 원자력 발전시스템이다.(중략)

• The Journal of Engineering Geology
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• v.28 no.1
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• pp.35-45
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• 2018

Imaging technologies are applied at various geological scales including pore scale, core scale and intermediate scale in order to characterize pore space of rocks as well as to map the fluid distribution in porous media. This technical report presents experimental results using core-flooding apparatus suited with imaging technology. Three different core samples, that are homogeneous, fractured and heterogeneous cores, were used to assess the two-phase fluid migration behavior as $CO_2$ displaces resident brine. We show that imaging technology can be effective in characterizing salt-precipitation, capillary pressure and spatio-temporal variation of trapping mechanisms.

• Macromolecular Research
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• v.14 no.4
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• pp.466-472
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• 2006

The kinetic behavior of emulsion polymerizations of styrene in the presence of sulfonated N-hydroxy ethyl aniline (SHEA) was investigated with two initiators: 2,2'-azobisisobutyronitrile (AIBN) and potassium persulfate (KPS). SHEA was synthesized using a stepwise polyurethane reaction method from 3-hydroxy-1-propane sulfonic acid sodium salt, isophorone diisocyanate (IPDI), and N-(2-hydroxyethyl) aniline. Stable core-shell poly(styrene/sulfonated N-hydroxy ethyl aniline, St/SHEA) latex particles were successfully prepared by using an appropriate amount of AIBN, in which SHEA plays the role of 'surfmer', i.e., acting as both a surfactant in the emulsion polymerization and a monomer in the chemical oxidative polymerization. The kinetic behavior was dissimilar to that of typical emulsion polymerization systems. A long inhibition period and low rate of polymerization were observed due to radical loss by the oxidative polymerization of SHEA. It was concluded, due to the low water-solubility of AIBN and retardation reaction by SHEA, that the initial loci of polymerization were monomer droplets. However, growing polymer particles as polymerization loci became predominant as polymerization proceeded. It was suggested that AIBN was more effective than KPS in the preparation of the core-shell type poly(St/SHEA) latex particles. With KPS, no substantial polymerization was observed in any of the samples.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.342-342
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• 2017

Rice seeds are a home to endophytic bacterial communities which serve as a source of the plant's endophytes. As rice undergo physiological and adaptive modifications through cross breeding in the process of attaining salinity tolerance, this may also lead to changes in the endophytic bacterial community especially those residing in the seeds. This study explores the community structure of seed bacterial endophytes as influenced by rice parental lineage, genotype and physiological adaptation to salinity stress. Endophytic bacterial diversity was studied through culture dependent technique, cloning and Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis. Results revealed considerably diverse communities of bacterial endophytes in the interior of rice seeds. The richness of ribotypes ranges from 5-14 T-RFs corresponding to major groups of bacterial endophytes in the seeds. Endophytic bacterial diversity of the salt-sensitive IR29 is significantly more diverse compared to those of salt-tolerant cultivars. Proteobacteria followed by Actinobacteria and Firmicutes dominated the overall endophytic bacterial communities of the indica rice seeds based on 16S rDNA analysis of clones and isolates. Community profiles show common ribotypes found in all cultivars of the indica subspecies representing potential core microbiota belonging to Curtobacterium, Flavobacterium, Enterobacter, Xanthomonas, Herbaspirillum, Microbacterium and Stenotrophomonas. Multivariate analysis showed that the bacterial endophytic community and diversity of rice seeds are mainly influenced by their host's genotype, physiological adaptation to salt stress and parental lineage.

• Fibers and Polymers
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• v.7 no.3
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• pp.229-234
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• 2006

Poly(vinyl acetate) (PVAc)/poly(vinyl alcohol) (PVA)/montmorillonite (MMT) clay nanocomposite microspheres with a core/shell structure have been developed via a suspension polymerization approach. In order to prepare the PVAc/ MMT and PVAc/PVA/MMT nanocomposite microspheres, which are promising precursor of PVA/MMT nanocomposite microspheres, suspension polymerization of vinyl acetate with organophilic MMT and heterogeneous saponification were conducted. A quaternary ammonium salt, cetyltrimethylammonium bromide, was mixed with the MMT in the monomer phase prior to the suspension polymerization. The rate of conversion decreased with an increase in MMT concentration. The incorporation of MMT into the PVAc was verified by FT-IR spectroscopy. Organic vinyl acetate monomers were intercalated into the interlayer regions of organophilic clay hosts and followed by suspension polymerization. Partially saponified PVA/MMT nanocomposite microspheres with a core/shell structure were successfully prepared by heterogeneous saponification.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.16-25
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• 2016

In severe loss of coolant accidents (LOCA), similar to those experienced at Fukushima Daiichi and Three Mile Island Unit 1, the zirconiumalloy fuel claddingmaterials are rapidlyheateddue to nuclear decay heating and rapid exothermic oxidation of zirconium with steam. This heating causes the cladding to rapidly react with steam, lose strength, burst or collapse, and generate large quantities of hydrogen gas. Although maintaining core cooling remains the highest priority in accident management, an accident tolerant fuel (ATF) design may extend coping and recovery time for operators to restore emergency power, and cooling, and achieve safe shutdown. An ATF is required to possess high resistance to steam oxidation to reduce hydrogen generation and sufficient mechanical strength to maintain fuel rod integrity and core coolability. The initiative undertaken by Electric Power Research Institute (EPRI) is to demonstrate the feasibility of developing an ATF cladding with capability to maintain its integrity in $1,200-1,500^{\circ}C$ steam for at least 24 hours. This ATF cladding utilizes thin-walled Mo-alloys coated with oxidation-resistant surface layers. The basic design consists of a thin-walled Mo alloy structural tube with a metallurgically bonded, oxidation-resistant outer layer. Two options are being investigated: a commercially available iron, chromium, and aluminum alloy with excellent high temperature oxidation resistance, and a Zr alloy with demonstratedcorrosionresistance.Asthese composite claddings will incorporate either no Zr, or thin Zr outer layers, hydrogen generation under severe LOCA conditions will be greatly reduced. Key technical challenges and uncertainties specific to Moalloy fuel cladding include: economic core design, industrial scale fabricability, radiation embrittlement, and corrosion and oxidation resistance during normal operation, transients, and severe accidents. Progress in each aspect has been made and key results are discussed in this document. In addition to assisting plants in meeting Light Water Reactor (LWR) challenges, accident-tolerant Mo-based cladding technologies are expected to be applicable for use in high-temperature helium and molten salt reactor designs, as well as nonnuclear high temperature applications.