• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.373-374
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• 2005

NaOCl (Sodium hydrochlorite) have similar smell of chloride and solution of straw color. And boiling point is $110^{\circ}C$, specific gravity is 1.0(50g/l)/1.1(100g/l), Value of pH is 12. NaOCl playa role as bleach, a oxidizer, a germicide, a decolorant, a deodorant, treatment of water supply and drainage, food addition agent because strong oxidation, bleaching, sterilization effect is had. When NaOCl is produced in electrolysis of seawater, this system is composed of injection system by directly electrolysis of salt water on the spot and sodium hydrochlorite generate a safe low concentration(0.4~0.8 %).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.473-476
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• 2008

In this paper, we designed the main mechanism of high throughput device for rod-cuts of spent fuel. For this, we analyzed the mechanical methods(slitting, ball mill, roller straightening) and chemical methods(muffle furnace, rotary kiln). As the results, methods of ball drop and rotary drum for concepts design were selected in the analysis step. For enhancement of oxidation rate, we devised the blades on the reactor with mesh type. Also, for enhancement of decladding rate, we designed ball size and rotation reactor with mesh type and devised the vacuum system for fission products. Mechanisms of oxidation and recovery can simultaneously handle the rod-cuts of spent fuel and independently recover. The results of mechanism design can be used for scale-up of high throughput device.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.612-618
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• 1997

$LiMn_2O_4$ powders were prepared by burning and subsequent calcination of PEG-metal nitrate precursor. After the burning stage of the precursor, some minor phases such as $Mn_2O_3$ (or $Mn_3O_4$), MnO, and carbonate were formed and single phases of $LiMn_2O_4$ were obtained by further calcinations above 400 ℃. From thermal analysis of the precursor, a violent thermal decomposition, which was indicated by a drastic weight loss accompanied by a sharp and strong exothermic peak, was observed and probably caused by an oxidation-reduction reaction between oxidizer and fuel. The formation of the minor phases could be explained in terms of the burning behavior of the precursor by employing valence concepts of propellant chemistry. The calcined powders were composed of submicron-sized but highly agglomerated particles and showed very broad particle size distribution.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.189-192
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• 2004

Test Facility for hot firing test of small size liquid rocket engine has been developed to research the cooing characteristics of kerosene for cylinder part especially. Propellants for the tests are kerosene and liquid oxygen as fuel and oxidizer respectively and they are fed by gaseous nitrogen. The engine components used hot firing test except for cylinder are cooled by tap-water. Valves for supply of propellants and coolants are controlled by pneumatically. System control and data recording are conducted automatically.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.282-287
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• 2004

Unielement combustion tests were conducted using coaxial bi-swirl injectors. Major experimental parameters were a recess length and a fuel-side swirl chamber. Combustion efficiency mainly depends on a mixing mechanism for the present coaxial swirl injectors. Low-frequency pressure excitations around 200Hz were observed for all injectors. However, dynamic behaviors considerably differ for an external and an internal mixing case controlled by a recess length. The internal mixing induces mixture to be biased at a specific frequency in a mass flow rate, which results in a relatively high amplitude of pressure fluctuations but results for the external mixing case show that fuel and oxidizer mixture flow carries more complicated, multiple wave characteristics due to broad mixing region as well as disintegration and merging phenomena of propellant films.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.69-72
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• 2011

Hot-firing tests were performed on the third sub-scale gas generator for development of a 75 ton-class liquid rocket engine. This paper deals with the analysis results of low-frequency combustion instabilities that were encountered during combustion tests of the gas generator. The low-frequency pressure fluctuations seem to be related to chamber pressure and pressure drops through oxidizer/fuel injectors.

• Journal of Aerospace System Engineering
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• v.4 no.3
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• pp.29-33
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• 2010

In this study, small hybrid rocket was launched and flight altitude was measured. Flight path of rocket was analyzed with exterior ballistics analysis result. The data acquisition equipment was loaded in rocket and two launch test were performed. HDPE was used as fuel and N20 as oxidizer for this study.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.50-57
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• 2021

Engine cool down process is necessary for the liquid rocket engines using cryogenic propellants in order to meet the requirement of engine inlet temperature. This paper evaluates the cool down characteristics of oxidizer supply pipeline and engine in prechill process prior to the engine firing tests, and calculate the quantity of liquid oxygen consumption.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.179-188
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• 2007

In this work $^{14}C\;and\;^3H$ distribution characteristics of spent resins from nuclear power plants(NPPs), pressurized water reactors(PWRs), was investigated. It was found that the recovery percent of $^{14}C$ by the wet oxidation-acid stripping was $81%{\sim}100%$ for the added activity range of $^{14}C,\;0.72\;Bq{\sim}460\;Bq$, and it was not affected by the kinds of stripping acids, 3N-HCl, $3\;N-HNO_3\;and\;3\;N-H_2SO_4$. And the recovery percent of $^3H$ by distillation using the same apparatus was $81%{\sim}101%$ for the added activity range of $^3H,\;0.60\;Bq{\sim}435\;Bq$. Among the tested stripping acids, 3\;N-HCl, $3\;N-HNO_3\;and\;3\;N-H_2SO_4$, only the trapped $^3H$ solution by distillation in $3\;N-H_2SO_4$ was compatible with the 3H scintillator, Ultimagold XR. Neither of the $^{14}C\;and\;^3H$ trapping solutions from the spent ion exchange resin samples by the wet oxidation-3 $N-H_2SO_4$ stripping contained gamma nuclides. However, some gamma nuclides, $^{60}Co,\;^{134}Cs,\;^{137}Cs\;and\;^{54}Mn$, were found in the trapped $^3H$ solutions of the spent resins by the wet oxidation-3 N-HCl stripping. It was the same for the $^3H$ trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). Meanwhile only two nuclides, $^{134}Cs,\;and\;^{134}Cs$, were found in the $^{14}C$ trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). It was found that most of the $^{14}C$ in the spent resins existed as inorganic carbon form, more than about 70% of the total $^{14}C$ content. Among the analyzed 30 spent ion exchange resin samples, the average concentration of $^{14}C$ and $^3C$ for the high radioactive samples, 8 samples, was $19000\;Bq/g{\pm}41000\;Bq/g,\;670\;Bq/g{\pm}460\;Bq/g$ and that for the low radioactive samples, 22 samples, was $4.2\;Bq/g{\pm}4.3\;Bq/g,\;6.0\;Bq/g{\pm}5.3\;Bq/g$, respectively. And the average $^{14}C/^3H$ ratio for the high radioactive samples, was higher, 28, than that of low radioactive samples, 0.70. Some linear relationship trend was found between the activity concentrations of $^{14}C\;and\;^3H$.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.647-653
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• 2007

The ultimate objective of this study is to develop a reliable oxygen-enriched combustion techniques especially for the case of the flue gas recycling in order to reduce the $CO_2$ emissions from practical industrial boilers. To this end a systematic numerical investigation has been performed, as a first step, for the resolution of the combusting flame characteristics of lab-scale LNG combustor. One of the important parameters considered in this study is the level of flue gas recycling calculated in oxygen enriched environment. As a summary of flame characteristics, for the condition of 100% pure $O_2$ as oxidizer without any flue gas recycling, the flame appears as long and thin laminar-like shape with relatively high flame temperature. The feature of high peak of flame temperature is explained by the absence of dilution and heat loss effects due to the presence of $N_2$ inert gas. The same reasoning is also applicable to the laminarized thin flame one, which is attributed to the decrease of the turbulent mixing. These results are physically acceptable and consistent and further generally in good agreement with experimental results appeared in open literature. As the level of $CO_2$ recycling increases in the mixture of $O_2/CO_2$, the peak flame temperature moves near the burner region due to the enhanced turbulent mixing by the increased amount of flow rate of oxidizer stream. However, as might be expected, the flue gas temperature decreases due to presence of $CO_2$ gas together with the inherent feature of large specific heat of this gas. If the recycling ratio more than 80%, gas temperatures drop so significantly that a steady combustion flame can no longer sustain within the furnace. However, combustion in the condition of 30% $O_2/70% $ $CO_2$ can produce similar gas temperature profiles to those of conventional combustion in air oxidizer. An indepth analyses have been made for the change of flame characteristics in the aspect of turbulent intensity and heat balance.