• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1687-1707
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• 2023

This paper presents a molten salt reactor (MSR) design parameter sensitivity study using a nodal dynamic modelling methodology with explicitly modified point kinetics equation and Mann's model for heat transfer. Six parameters that can impact MSR safety are evaluated. A MATLAB-Simulink model inspired by Thorcon's 550MWth MSR is used for parameter evaluations. A safety envelope was formed to encapsulate power, maximum and minimum temperature, and temperature-induced reactivity feedback. The parameters are perturbed by ±30%. The parameters were then ranked by their subsequent impact on the considered safety envelope, which ranks acceptable parameter uncertainty. The model is openly available on GitHub.

• Korean Journal of Materials Research
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• v.9 no.2
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• pp.211-216
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• 1999

Corrosion behavior of austenitic stainless steels of SUS 316L and SUS304L in molten salt of LiCl and $LiCl/Li_2O$ has been investigated in the temperature range of $650~850^{\circ}C$. Corrosion products of SUS316L and 304L in hot molten salt consisted of two layers-an outer layer of Li(CrFe)$O_2$and an inner layer of$Cr_2O_3$. The corrosion layer was uniform in molten salt of LiCl, but the intergranular corrosion occurred in addition to the uniform corrosion in mixed molten salt of LiCl/$Li_2O$. The corrosion rate increased slowly with the increase of temperature up to $750^{\circ}C$, but above $750^{\circ}C$ rapid increase in corrosion rate observed. SUS316L stainless steel showed slower corrosion rate than SUS 304L, exhibiting higher corrosion resistance in the molten salt.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.423-427
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• 2018

For diamond/metal composites it is better to use diamond particles coated with metal carbide because of improved wettability between the diamond particles and the matrix. In this study, the coating of diamond particles with a chromium carbide layer is investigated. On heating diamond and chromium powders at $800{\sim}900^{\circ}C$ in molten salts of LiCl, KCl, $CaCl_2$, the diamond particles are coated with $Cr_7C_3$. The surfaces of the diamond powders are analyzed using X-ray diffraction and scanning electron microscopy. The average thickness of the $Cr_7C_3$ coating layers is calculated from the result of the particle size analysis. By using the molten salt method, the $Cr_7C_3$ coating layer is uniformly formed on the diamond particles at a relatively low temperature at which the graphitization of the diamond particles is avoided. Treatment temperatures are lower than those in the previously proposed methods. The coated layer is thickened with an increase in heating temperature up to $900^{\circ}C$. The coating reaction of the diamond particles with chromium carbide is much more rapid in $LiCl-KCl-CaCl_2$ molten salts than with the molten salts of $KCl-CaCl_2$.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.3-9
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• 2002

The corrosion behavior of alloys in a molten salt was investigated along with the oxidation characteristics in the air. The basic composition of alloys in the study was Fe-25Ni-7Cr with Si and RE(rare-earth metal) as additives. The corrosion rate of the alloys was low in a molten salt of LiCl while the rate was high in the mixed molten salt of LiCl and $Li_2O$. When Si is added to the base alloy of Fe-25Ni-7Cr, corrosion resistance was improved as the Si content is increased up to 3%, however, it was observed that the corrosion resistance was getting worse as the Si content is increased. The base alloy with 2.43% of Si and 0.9% of RE(KSA-65), showed higher corrosion rate compared to that of KSA-63 alloy with an equivalent amount of only Si. The corrosion resistance of KSA-65 was similar to that of the base alloy(KSA-60). The oxidation resistance of KSA-65 alloy was greatly increased even at $850^{\circ}C$ for a long term exposure.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.535-544
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• 1996

In the development of Molten Carbonate Fuel Cell, one of the serious problems is the dissolution of cathode material. Therefore, the development of the alternative cathode which is stable in molten carbonate is needed. In this research, the licoo, was chosen as alternative cathode material. $LiCoO_2$ powder was synthesized by high temperature calcination method and by citrate sol-gel method. And its structure and physical iharacteristics were analyzed by XRD, 1 R, TCA and porosimeter. The conductivity and solubility of $LiCoO_2$ electrode were also measured. Homogeneous $LiCoO_2$ Powder was obtained by citrate sol-Rel method at 445$^{\circ}C$, however, obtained above 75$0^{\circ}C$ by high temperature calcination method. Homogeneous particle size distribution and fine powder were obtained by the citrate sol-Rel method. $LiCoO_2$ electrode showed higher electric conductivity ($1.7 $\Omega$^{-1}cm^{-1}$) than NiO (0.1 $\Omega$^{-9} cm^{-1}) at $650^{\circ}C$. The solubilities of $LiCoO_2$ electrode in electrolyte were varies 0.6 to 1.0 ppm during 200 hours. So, the solubilities of $LiCoO_2$ were much lower than that of NiO.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.121-128
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• 2014

This study aims to develop a simulation bed for the mechanical balance of plants of high temperature fuel cells such as molten carbonate fuel cells. For using fuel cells in transportation, the optimization of the balance of plants should be considered. In this study, the dynamic model of a molten carbonate fuel cell and the model's responses to inlet gas composition, pressure, flow rate, and stack temperature were analyzed. On/off simulation was performed for testing the dynamic model's feasibility. The simulation results are in reasonable agreement with the experimental results from published literatures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.501-508
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• 1996

Strontium barium niobate powders were prepared by NaCl-KCl molten salt, and reaction process and morphology change of strontium barium niobate were investigated as a function of reaction temperature, time, and amount of molten salt. With increasing the reaction temperature and time, the reacted fraction was increased and the morphology of powder was changed from lumpy shape into meedle-like shape. With increasing the amount of molten salt, reacted fraction was increased rapidly, but the morphology of powder was changed from needle-like shape into spherical shape. Strontium barium niobate powder, over 90 % in fraction reacted, was obtained from the reaction conditions at $1000^{\circ}C$ for small flux ratio (=1) and at $650^{\circ}C$ for large flux ratio (=4).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.209-229
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• 2022

This work provided a review of three techniques-(1) spectrochemical, (2) electrochemical, and (3) spectroelectrochemical-for molten salt medias. A spectroelectrochemical system was designed by utilizing this information. Here, we designed a spectroelectrochemical cell (SEC) and calibrated temperature controllers, and performed initial tests to explore the system's capability limit. There were several issues and a redesign of the cell was accomplished. The modification of the design allowed us to assemble, align the system with the light sources, and successfully transferred the setup inside a controlled environment. A preliminary run was executed to obtain transmission and absorption background of NaCl-CaCl₂ salt at 600℃. It shows that the quartz cuvette has high transmittance effects across all wavelengths and there were lower transmittance effects at the lower wavelength in the molten salt media. Despite a successful initial run, the quartz vessel was mated to the inner cavity of the SEC body. Moreover, there was shearing in the patch cord which resulted in damage to the fiber optic cable, deterioration of the SEC, corrosion in the connection of the cell body, and fiber optic damage. The next generation of the SEC should attach a high temperature fiber optic patch cords without introducing internal mechanical stress to the patch cord body. In addition, MACOR should be used as the cell body materials to prevent corrosion of the surface and avoid the mating issue and a use of an adapter from a manufacturer that combines the free beam to a fiber optic cable should be incorporated in the future design.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.331-337
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• 2017

Thermal batteries, reserve power source, is activated by melting of molten salt at the temperature range of $350{\sim}550^{\circ}C$. To immobile the molten state electrolyte when the thermal battery is activated, the binder must be added in electrolyte. Usually, molten salts include 30~40 wt% of MgO binder to ensure electrical insulation as well as safety. However, the conventional MgO binder tends to increase ionic conductive resistance and thus the inclusion of the binder increases the total impedance of the battery. This paper mainly focused on the study of yttria stabilized zirconia (YSZ) as an alternative binder for molten salt. The chemical stability between the molten salt and YSZ is measured by XRD and DSC. And the sufficient path for ionic conduction on molten salt could be confirmed by the enhanced wetting behavior and the enlarged pore size of YSZ. The electrochemical properties were analyzed using single cell tests so that it showed the outstanding performance than that using MgO binder.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.1-6
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• 2008

There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The method developed in this study decreases the molten metal processing and settling time compared to the existing methods and improves the workers' health, safety, and environment because there is no pollution in processes.