• Nuclear Engineering and Technology
• /
• v.45 no.6
• /
• pp.731-744
• /
• 2013

Energy security is a topic of high importance to many countries throughout the world. Countries with access to vast energy supplies enjoy all of the economic and political benefits that come with controlling a highly sought after commodity. Given the desire to diversify away from fossil fuels due to rising environmental and economic concerns, there are limited technology options available for baseload electricity generation. Further complicating this issue is the desire for energy sources to be sustainable and globally scalable in addition to being economic and environmentally benign. Nuclear energy in its current form meets many but not all of these attributes. In order to address these limitations, TerraPower, LLC has developed the Traveling Wave Reactor (TWR) which is a near-term deployable and truly sustainable energy solution that is globally scalable for the indefinite future. The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel. With advanced technological development and added cost, TWRs are also capable of reusing both their own used fuel and used fuel from LWRs, thereby eliminating the need for enrichment in the longer term and reducing the overall societal waste burden. This paper describes the origins and current status of the TWR development program at TerraPower, LLC. Some of the areas covered include the key TWR design challenges and brief descriptions of TWR-Prototype (TWR-P) reactor. Selected information on the TWR-P core designs are also provided in the areas of neutronic, thermal hydraulic and fuel performance. The TWR-P plant design is also described in such areas as; system design descriptions, mechanical design, and safety performance.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3246-3252
• /
• 2009

The interest on the recovery of thermal energy using the waste has been rising to solve the problems of continuous increase of waste generation and the depletion of the fossil fuel recently. The incineration has been used most popularly as a treatment process of the waste for the energy recovery. However, it is expected that incineration and design cost will increase in the treatment of air contaminant emitted from incinerator. This research has simulated the actual incinerator and the flue gas treatment system using the Aspen plus which is the software to simulate the chemical process. The incineration process is composed of the 1st and 2nd combustor to burn the waste, SNCR process to reduce the $NO_x$ using the urea, and the steam generation process to save the energy during incineration. The $Ca(OH)_2$ slurry was used as an acid gas (HCl, $SO_2$) treatment materials and the removal efficiency for the products from the neutralization of acid gas in SDA and combustion ash was simulated at the bag filter. The simulation result has been corresponded with the treatment efficiency of emitted gas from the actual industrial waste incinerator and it is presumed to be used to forecast the efficiencies of flue gas treatment system in the future.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.751-758
• /
• 2000

A study was carried out on the dissolution of spent PWR fuels and performed on the fuels and the separation of iodide for the quantitative analysis using SIMFUEL which has chemical composition of a simulated spent PWR fuel (burn-up; 35,000 MWd/MTU and cooling time; 10 years). To dissolve the SIMFUEL effectively and to minimize the formation of volatile iodine through dissolution process, the optimum ratio of mixed acid ($HNO_3/HCl$ 80: 20 mol%) was established and ozone gas was purged. In the separation step of iodine with $CCl_4$, $NH_2OH{\cdot}HCl$ was used for reducing ${IO_3}^-$ to $I_2$.The optimum acidity of the dissolved solution and the added of $NH_2OH{\cdot}HCl$ were 2.5 M and more than $1.5{\times}10^{-3}mole$, respectively. The recovery of iodide by ion chromatography was $82.8{\pm}4.1%$ and the total yield was corrected by gamma spectrometery using $^{131}I$ as a tracer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.5
• /
• pp.21-30
• /
• 2008

The fuel cell generation convert fuel source, and gas directly to electricity in an electro-chemical process. Unlike traditional and conventional turbine engines, the process of fuel cell generation do not burn the fuel and run pistons or shafts, and it has not revolutionary machine, so have fewer efficiency losses, low emissions and no noisy moving parts. A high power density allows fuel cells to be relatively compact source of electric power, beneficial in application with space constraints. In this system, the fuel cell itself is nearly small-sized by other components of the system such as the fuel reformer and power inverter. So, the fuel cell energy's stationary fuel cells produce reliable electrical power for commercial and industrial companies as well as utilities. In this paper, a fuel cell system has been modeled using PSCAD/EMTDC to analyze its electric signals and characteristics. Also the power quality of the fuel cell system has been evaluated and the problems which can be occurred during its operation have been studied by modeling it more detailed. Particularly, we have placed great importance on its power quality and signal characteristics when it is connected with a power grid.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.451-457
• /
• 2019

In this study, the characteristics of coffee grounds were reviewed by making them from solid fuel through heat-drying and oil-drying method. The differences in the higher calorific power by each dried sample were compared. And industrial analysis using the thermogravimetric analyzer was considered for applicability to organic waste and oily samples. Before and after drying, the surface of the specimen was observed with SEM equipment and the ingredients were measured through the EDS equipment. As a result, no other hazardous substances, such as heavy metals, were measured. Next, The differences between thermal decomposition and combustion reactions were considered through the TG and DTG curves. As a result, it is that the oil-dried coffee grounds is longer to burn than the heat-dried coffee grounds. Finally, the combustion gases emitted through the thermogravimetric analyzer were collected and the carbon monoxide and carbon dioxide performed qualitative and quantitative analysis using GC over time.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.12a
• /
• pp.62-62
• /
• 2020

Ginseng is a shade-plant cultivated using shading facilities. However, at too low light levels, root growth is poor, and at high light levels, the destruction of chlorophyll reduces the photosynthesis efficiency due to leaf burn and early fall leaves. The ginseng has a lightsaturation point of 12,000~15,000 lux when grown at 15 to 20℃ and 9,500 lux at 25℃. This study was conducted to select the optimal light intensity of 3-year-old ginseng grown in blue-white film plastic house. The seeds were planted in the blue-white film plastic house with different light receiving rate (March 17, 2020). Between April and September, the average air temperature in the house was 20.4-20.7℃. Average soil temperature was 18.3℃-18.5℃. The chemical properties of the test soil was as follows. The pH level was 7.0-7.4, EC was 0.5-0.6 dS/m, OM was at the levels of 33.6-37.7 g/kg, P₂O₅ was 513.0-590.8 mg/kg, slightly higher than the allowable 400 mg/kg. The amount of light intensity, illuminance, and solar radiation in the blue-white film house was increased as the light-receiving rate increased and the amount of light intensity was found to be 9-14% compared to the open field, 8-13% illuminance and 9-14% solar irradiation respectively. The photosynthesis rate was the lowest at 3.1 µmolCO²/m²/s in the 9% light blue-white plastic house and 4.2 and 4.0 µmolCO²/m²/s in the 12% and 14% light blue-white plastic house, respectively. These results generally indicate that the photosynthesis of plants increases with the amount of light, but the ginseng has a lower light saturation point at high temperatures, and the higher the amount of light, the lower the photosynthetic efficiency. The SPAD (chlorophyll content) value decreased as the increase of light-receiving rate, and was the highest at 32.7 in 9% light blue-white plastic house. Ginseng germination started on April 11 and took 13-15 days to germinate. The overall germination rate was 82.9-85.8%. The plant height and length of stem were long in the 9% light-receiving plastic house. The diameter of stem was thick in the 12-14% light-receiving plastic house. In the 12% and 14% light-receiving plastic house, the length and diameter of taproot was long and thick, so the fresh weight of root per plant was 20 g or more, which was heavier than 16.9 g of the 9% light-receiving plastic house. The disease incidence (Alternaria blight, Gray mold and Damping-off etc.) rate were 0.9-2.7%. The incidence of Sclerotinia rot disease was 7.5-8.4%, and root rot was 0-20.0%. The incidence ratio of rusty root ginseng was 34.4-38.7% level, which was an increase from the previous year's 15% level.

• Horticultural Science & Technology
• /
• v.29 no.4
• /
• pp.298-305
• /
• 2011

This study was conducted to enhance the stem firmness of standard chrysanthemum 'Baekma' bred in Korea for commercial quality improvement and inhibition of stem breaking during transportation through foliar spray with calcium agents. Calcium agent screening 'Baekma' was examined using $CaCl_2{\cdot}2H_2O$, $Ca(NO_3)_2{\cdot}4H_2O$, and OS-Ca (natural liquid calcium compounds extracted from oyster shell) depending on each concentration (0, 0.001, 0.01, 0.1, and 1.0%, respectively). All calcium agents sprayed with 1.0% caused chemical injury such as stem bending or leaf burn. OS-Ca also showed more sensitive response to chemical injury than the other calcium agents because OS-Ca was absorbed very well by 'Baekma' leaves. Maximum stem firmness measured during the final harvest was greater in OS-Ca than in the other calcium agents. Especially, maximum stem firmness was greatest in 0.01% OS-Ca. However, elastic strength and maximum bending stress were greater in 0.001% OS-Ca than in the others. Thus, OS-Ca ranged from 0.005 to 0.05%, which did not show any chemical injury, was finally selected as the first candidate for hardening the stem of 'Baekma'. The next experiment using OS-Ca was conducted with the concentrations of 0, 0.005, 0.01, and 0.05%, respectively. From the results, 0.05% OS-Ca showed better plant growth and parameters such as plant height, stem diameter (upper and middle part), the number of leaves, and dry weights of each part than the other concentrations of OS-Ca and control. As for stem firmness depending on OS-Ca concentration, the Ca content within stem, maximum firmness, elastic strength, and maximum bending stress of stem in 'Baekma' sprayed with 0.05% OS-Ca showed the highest values among all the treatments and it turned out to be very high level of significance between control and OS-Ca treatments. However, the area and percentage of the inside cavity within horizontal stem section in 'Baekma' did not show any significance between any treatments including control. Thus, stem firmness of 'Baekma' did not show any correlation with the inside cavity area of stem. In conclusion, we recommend foliar sprays with 0.05% OS-Ca at vegetative growth stage to enhance stem firmness of 'Baekma' during transportation.

• Journal of the Korean Wood Science and Technology
• /
• v.10 no.1
• /
• pp.5-37
• /
• 1982

Plywood used for construction as a decorative inner material is inflammable to bring large fire accidents and burn out human life and their properties. To diminish the fire disaster, fire retardant plywood has been required indeed. In the methods of manufacturing the fire retardant plywood the soaking method is occasionally used. However after soaking plywood into fire retardant chemical solutions, redrying of soaked plywood is the most important. In this study, 3.5mm thin and 5.0mm thick plywoods were selected for fire retardant treatment. Treating solutions were prepared for 20% dilute solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate, borax-boric acid and minalith, and water solution. 1-, 3-, 6-, and 9 hour-soaking treatments were applied and after treatments hot plate drying was applied to those treated plywoods at $90^{\circ}C$, $120^{\circ}C$ and $150^{\circ}C$, of press temperature. Drying rates, drying curves, water absorption rates of fire retardant chemicals, weight per volume and fire retardant degree of plywood were investigated. The results may be summarized as follows: 1. The plywoods treated with ammonium sulfate, monoammonium phosphate and diammonium phosphate and diammonium phosphate showed increase of chemical absorption rate with proportion to increase of treating time, but not in case of the plywood treated with borax-boric acid and minalith. 2. In the treatment of definite time, the absorption rate per unit of volume of plywood showed higher in thin plywood (thickness of 3.5mm) than in thick plywood (thickness of 5.0mm). In both thin and thick plywoods, the highest absorption rate was observed in 9 hour-treatment of ammonium sulfate. The value was 1.353kg/$(30cm)^3$ in thin plywood and 1.356kg/$(30cm)^3$ in thick plywood. 3. The volume per weight of plywood after chemical treatment increased remarkably and. after hot plate drying, the values were to a little extent higher than before chemical treatment. 4. The swelling rates of thickness in chemical-treated plywoods increased similarly with that of water-treated plywood in 1- and 3 hour-treatment of both thin and thick plywoods. But in 6- and 9 hour-treatment, the greater increased value showed in water-treated ply wood than any other chemical, especially in thick plywood. 5. The shrinkage rates after hot plate drying showed the same tendency as the swelling rate, and the rate showed the increasing tendency with proportion to increase of treating time in thick plywood of both chemical and water treatments. 6. Among drying curves, the curves of water-treated plywood placed more highly than chemical-treated plywood without-relation to thickness in 6- and 9 hour-treatment except in 1- and 3 hour-treatment. 7. The drying rate related to thickness of treated plywood, was twice above in thin plywood compared with thick plywood. 8. The drying rate remarkably increased with proportion to increase of the plate temperature and, the values were respectively 1.226%/min., 6.540%/min., 25.752%/min. in hot plate temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in thin plywood and 0.550%/min., 2.490%/min, 8.187%/min, in hot plate temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in thick plywood. 9. In the treatment at $120^{\circ}C$ of hot plate temperature, the drying rates of chemical-treated plywood showed the highest value in monoammonium phosphate of thin plywood and in diammonium phosphate of thick plywood. But the drying rate of water-treated plywood was highest in 6- and 9 hour-treatment. 10. The fire retardant degree of chemical-treated plywood was higher than that of the untreated plywood as shown in loss of weight, burning time, flame-exhausted time and carbonized area. 11. The fire-retardant effect among fire retardant chemicals were the greatest in diammonium phosphate, the next were in monoammonium phosphate and ammonium sulfate, and the weakest were in borax-boric and minalith.

• Journal of Radiation Protection and Research
• /
• v.15 no.2
• /
• pp.27-39
• /
• 1990

Appreciable radiation exposures certainly were occurred in the reactor burn-up, the nuelear fall-out and the surroundings of nuclear installations with radioactive effluents. Therefore, radioactive nuclides is not only potentially hazardous to workers of nuclear power plants and related industrials, but also the wokers who handle radioactive nuclides in biochemical research and nuclear medicine diagnostics. And in the case of occurring the nuclear accidents, the early medical treatment of radiation injury should be necessary but little is established medical procedures to decontaminate the victims of internal contamination of radioactive nuclides in korea. Accordingly, to achieve the basic data for protective roles and medical treatment of radiation injury, the present studies were carrid out to evaluate the decontamination of uranium by the chemical drugs. The results observed were summarized as follows: 1. The combined treatmet group of sodium bicarbonate and saline with uranyl nitrate injection simultaneously and the dithiothreitol group that was administered 30 minutes after uranyl nitrate injection were increased significantly in the change of body weight than uranyl nitrate-only group (P<0.005). 2. All the experimental groups were increased the fluid intake and urine volume on the uranyl nitrate-induced acute renal failure. but the combined treatment group of sodium bicarbonate and saline with uranyl nitrate injection simultaneously and the dithiothreitol group that was administered 30 minutes after uranyl nitrate injection have the higher increment of fluid intake and urine volume (P<0.05). 3. When sodium bicarbonate and saline was treated with uranyl nitrate injection simultaneously. and dithiothreitol was administered 30 minutes after uranyl nitrate injection. there was significantly reduced in BUN concentration (P<0.01). 4. When dithiothreitol was administered 30 minutes after uranyl nitrate injection. there was reduced more significantly on the increment of serum creatinine concentration than that observed in uranyl nitrate-only group(P<0.01). but when the combined treatment of sodium bicarbonate and saline with uranyl nitrate simultaneously, there was still. albeit much less marked. decrease in serum creatinine concentration. 5. The sodium bicarbonate and saline was treated with uranyl nitrate simultaneously and dithiothreitol was administered at 30 minutes after uranyl nitrate were excreted markedly higher urine creatinine concentration than the uranyl nitrate-only group. 6. Uranyl nitrate has been used in experimental animals to produce hydropic degeneration and swelling of proximal tubules, disappearance of microvilli and brush border or necrosis in the kidney and centrilobular necrosis, congestion, and telangiectasia of the liver. When the sodium bicarbonate and saline was treated with uranyl nitrate simultaneously, and dithiothreitol was administered. 30 minutes after uranyl nitrate, there was more marked the protective effect than uranyl nitrate-only group. Finally, if the sodium bicarbonate and saline may administered as quickly as possible each time that some risk for internal contamination, with uranium, and dithiothreitol is administered 30 minutes after uranium contamination, there ameliorates the course of uranyl nitrate-induced acute renal failure.and this effect is assocciated with prevention of uranium (heavy metal)-induced alterations in BUN, serum creatinine, urine creatinine, fluid intake, urine volume and body weight.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1981.05a
• /
• pp.5.3-6
• /
• 1981

There are too many kinds of esophageal corrosive agents, such as sodium hydrochloride, acetic acid, hydrochloric acid, etc. Esophageal burn due to above chemical agents are decreasing recently, but still many patients visited to the hospital because of swallowing corrosive agents for the purpose of suicide or accidentally. Among the treatment of corrosive injury of the esophagus, prevention of esophageal stricture is the key point. Recently various methods are using as the treatment of corrosive esophagitis and prevention of esophageal stricture. 51 cases of corrosive injury of the esophagus who had been admitted and treated at the Dept. of Otolaryngology, Han Yang University Hospital during past 9 years (from May 1972 to Dec. 1980) were evaluated and report the result about age distribution, sex incidence, monthly distribution, cause of swallowing, swallowing agents, arriving time at hospital after swallowing, changes on oral and pharyngeal mucosa, laboratory findings, emergency treatment and treatment during admission, treatment follow up results and complications with review of liter ature. Following results were obtained; 1. Female patients 27 cases (52.9%) were more than male patients 24 cases (47.1%) and its ratio was 1.13 : 1. 2. Age distribution showed predilection for age of 21-30 with 20 cases(39.2%), and 11-20 with 11 cases (21.6%), 31-40 with 7 cases(13.7%), over 50 with 7 cases (13.7%) were following. 3. Monthly distribution showed predilection for March with 8 cases(15.7%), and April, July with 7 cases (13.7%), September with 6 cases(l1.8%), October 5 cases(9.8%) were following. 4. For the purpose of suicide was the most cause of swallowing with 40 cases(78.4%), and accidentally swallowing 11 cases(21.6%). 5. Acetic acid was the most swallowing agent with 24 cases (47.0%), and hydrochloric acid 11 cases (21.5%), lye 8 cases(15.7%), iodine 2 cases(3.9%) were following. 6. Arriving time at the hospital after swallowing showed predilection for within 12 hours with 42 cases (82.4%), and from 12 hours to 24 hours with 4 cases(7.8%) was next. 7. Moderate change with injection and swelling was the prevalent change on oral and pharyngeal mucosa with 20 cases(39.2%) and severe cases with ulceration 18 cases (35.3%), mild cases with injection 10 cases (19.6%) were following. 8. Leukocytosis was seen on 40 cases (78.4%), and increased Hct. was seen 31 cases (60.8%). On urine analysis, 14 cases(27.5%) showed over 1.030 S.G., and proteinuria was seen on 25 cases(49.0%), glycosuria was seen on 5 cases(9.8%) and hematuria was seen on 6 cases(11.8). 9. Gastric lavage was done on 30 cases (58.8%) as emergency treatment and on 3 cases(5.9%) tracheostomy was done for the airway keeping. 10. As methods of treatment during admission, L-tube insertion was done on 50 cases (98.0%), antibiotics was given to 49 cases (96.1%), steroid and antacid were given to 46 cases(90.2%). 11. 36 cases(70.6%) were in favorable condition after proper treatment, but 2 cases (3.9%) were expired during admission, 4 cases (7.8%) showed esophageal stricture in-spite of treatment, and 1 case(2.0%) showed pyloric stenosis. 12. Complications were observed in 8 cases (17.7%). Renal failure (4 cases), aspiration pneumonia (2 cases), upper G-I bleeding (1 cases), and diabetic coma (1 cases) were seen in order of frequency.