Domestic commercial low- and intermediate-level radioactive waste storage containers are manufactured using 1.2 mm thick cold-rolled steel sheets, and the outer surface is coated with a thin layer of primer of 10~36 μm. However, the outer surface of the primer of the container may be damaged due to physical friction, such as acceleration, resonance, and vibration during transportation. As a result, exposed steel surfaces undergo accelerated corrosion, reducing the overall durability of the container. The integrity of storage containers is directly related to the safety of workers. Therefore, the development of storage containers with enhanced durability is necessary. This paper provides an analysis of mechanical properties related to the durability of WC (tungsten carbide)-based coating materials for developing low- and intermediate-level radioactive waste storage containers. Three different WC-based coating specimens with varied composition ratios were prepared using HVOF (high-velocity oxy-fuel) technique. These different specimens (namely WC-85, WC-73, and WC-66) were uniformly deposited on cold-rolled steel surfaces ensuring a constant thickness of 250 μm. In this work, the mechanical properties of the three different WCbased coaitng materials evaluated from the viewpoints of microstructure, hardness, adheision force between substrate and coating material, and wear resistance. The cross-sectional SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) images revealed that elements W (tungsten), C (carbon), Ni (nickel), and Cr (chromium) were uniformly distributed within the each coating layers which was approximately 250 μm thick. The average hardness values of HWC-85 and HWC-73 were found to be 1,091 Hv (Vickers Hardness) and 1,083 Hv, respectively, while the HWC-66 exhibited relatively lower hardness value of 883 Hv. This indicates that a higher WC content results in increased hardness. Adhesion force between and substrates and coating materials exceeded 60 MPa for all specimens, however, there were no significant differences observed based on the tungsten carbide content. Furthermore, a taber-type abrasion tester was used for conducting abrasion resistance tests under specific conditions including an H-18 load weight at 1,000 g with rotational speed set at 60 RPM. The abrasion resistance tests were performed under ambient temperatures (RT: 23±2°C) as well as relative humidity levels (RH: 50±10%). Currently, the ongoing abrasion resistance tests will include some results in this study.
This study focuses on the development of coatings designed for storage containers used in the management of radioactive waste. The primary objective is to enhance the shielding performance of these containers against either gamma or neutron radiation. Shielding against these types of radiation is essential to ensure the safety of personnel and the environment. In this study, tungsten and boron cabide coating specimens were manufactured using the HVOF (High-Velocity Oxy Fuel) technuqe. These coatings act as an additional layer of protection for the storage containers, effectively absorbing and attenuating gamma and neutron radiation. The fabricated tungsten and boron carbide coating specimens were evaluated using two different testing methods. The first experiment evaluates the effectiveness of a radiation shielding coating on cold-rolled steel surfaces, achieved by applying a mixture of WC (Tungsten Carbide) powders. WC-based coating specimens, featuring different ratios, were prepared and preliminarily assessed for their radiation shielding capabilities. In the gamma-ray shielding test, Cs-137 was utilized as the radiation source. The coating thickness remained constant at 250 μm. Based on the test results, the attenuation ratio and shielding rate for each coated specimen were calculated. It was observed that the gammaray shielding rate exhibited relatively higher shielding performance as the WC content increased. This observation aligns with our findings from the gamma-ray shielding test and underscores the potential benefits of increasing the tungsten content in the coating. In the second experiment, a neutron shielding material was created by applying a 100 μm-thick layer of B4C (Boron Carbide) onto 316SS. The thermal neutron (AmBe) shielding test results demonstrated an approximate shielding rate of 27%. The thermal neutron shielding rate was confirmed to exceed 99.9% in the 1.5 cm thick SiC+B4C bulk plate. This indicates a significant reduction in required volume. This study establishes that these coatings enhance the gamma-ray and neutron shielding effectiveness of storage containers designed for managing radioactive waste. In the future, we plan to conduct a comparative evaluation of the radiation shielding properties to optimize the coating conditions and ensure optimal shielding effectiveness.
APro, a modularized process-based total system performance assessment framework, was developed at the Korea Atomic Energy Research Institute (KAERI) to simulate radionuclide transport considering coupled thermal-hydraulic-mechanicalchemical processes occurring in a geological disposal system. For reactive transport simulation considering geochemical reactions, COMSOL and PHREEQC are coupled with MATLAB in APro using an operator splitting scheme. Conventionally, coupling is performed within a MATLAB interface so that COMSOL stops the calculation to deliver the solution to PHREEQC and restarts to continue the simulation after receiving the solution from PHREEQC at every time step. This is inefficient when the solution is frequently interchanged because restarting the simulation in COMSOL requires an unnecessary setup process. To overcome this issue, a coupling scheme that calls PHREEQC inside COMSOL was developed. In this technique, PHREEQC is called through the “MATLAB function” feature, and PHREEQC results are updated using the COMSOL “Pointwise Constraint” feature. For the one-dimensional advection-reaction-dispersion problem, the proposed coupling technique was verified by comparison with the conventional coupling technique, and it improved the computation time for all test cases. Specifically, the more frequent the link between COMSOL and PHREEQC, the more pronounced was the performance improvement using the proposed technique.
APro, a modularized framework of the process-based total system performance assessment, has been developed by KAERI to simulate the radionuclide transport in geological disposal system considering multi-physics phenomena. However, the target problem including more than 10,000 boreholes and over 100,000 years of simulation time is computationally challenging to deal with numerical solvers provided by COMSOL Multiphysics constituting APro. To alleviate the computational burden, machine learning (ML) techniques have been studied to develop a surrogate model replacing the heavy computation part. In recent studies, attempts have been made to integrate the knowledge of physics and numerical methods into the ML model for partial differential equations (PDEs). Unlike conventional ML approaches solely relying on data-driven method, the integration can help to make the ML model more specialized for solving PDEs. The hybrid neural network (NN) solver method is one of the strategies to develop more efficient PDE solver by interleaving NN with numerical solvers like finite element method (FEM). The hybrid NN model on the premise of numerical solver is easier to train and more stable than the purely data-driven model. For example, one previous study has used the hybrid NN model as a corrector for an incomplete numerical solver for the advection-diffusion problem. In every time step of simulation, NN corrects the error of incomplete solution obtained by a relaxed numerical solver with coarse meshing. The simulation in the next time step starts from the corrected solution, so NN interacts with the numerical solver iteratively. If the corrector is successfully trained, the incomplete but fast solver with corrector can provide reliable results comparable to the original massive solver. This study adopts the hybrid concept to develop a surrogate model for the near-field region, which is the heavy computation part in the simulation of geological disposal system. Various incomplete models such as coarse meshing or emptying the borehole domain are studied to construct a hybrid NN solver. This study also covers how to embed the hybrid NN in COMSOL Multiphysics to train and use it during the simulation.
This study was conducted to estimate the effect of home or hetero fermentative lactic acid bacteria(LAB) on chemical composition, fermentation quality, and aerobic stability of rye silage. Rye forage was harvested at dough stage(28.9% of dry matter), chopped to 3-5 cm length, and divided into 4 piles for different inoculations as treatment, following 1) No additives(CON); 2) Lactobacillus plantarum at rate of 1.5 x 105 cfu/g of fresh forage(LP); 3) L. buchneri at rate of 1.2 x 105 cfu/g of fresh forage(LB); and 4) Mixture of LP and LB at 1:1 ratio(MIX). Rye silage was ensiled into 20 L bucket silo in quadruplicate for 0, 1, 4, 7, and 100 day periods. After 100 days of ensiling, the silage treated with LB had lower acid detergent fiber content(p<0.05), but higher in vitro dry matter digestibility(p<0.05). The LB and MIX reduced (p<0.05) pH more rapidly than CON and LP across the ensiling days, but had no difference on 100 days. Silage treated LP had lowest(p<0.05) acetic acid, but highest(p<0.05) propionic acid. In contrast, LB treated silage had highest(p<0.05) acetic acid, but lowest(p<0.05) propionic acid with the absence of butyric acid. On microbial count, LP treated silage had lowest(p<0.05) LAB, yeast, and aerobic stability, whereas LB and MIX treated silages had highest(p<0.05). Mold was not detected across all silages. Therefore, it could be concluded that heterofermentative LAB solely or combo with homofermentative LAB might improve in vitro dry matter digestibility, fermentation characteristics, and aerobic stability of rye silage harvested at dough stage.
Cryopreservation of avian semen is a useful tool to preserve genetic resource for aim of preventing extinction induced by infectious disease like avian influenza. Unlike those of mammals, data from chicken cryopreserved semen has not been showed feasible results. So, various cryoprotectants and diluents have been examined in many methods. In this report, as a major ingredient of avian seminal plasm, glutamine was substituted by alanyl glutamine to enhance physiological stability of chicken semen during freezing. We studied effect of glycerol and Dimethylacetamide(DMA) on motility and progressive motility of spermatozoa using glutamine diluent(EK-G) or alanyl glutamine diluent(EK-A) condition. The semen of Ogye was collected twice a week by the dorso-abdominimal massage method and diluted with same volume of EK-G or EK-A at 25℃ and stored for 10 min at 4℃ in cold chamber. Glycerol or DMA was added to diluted semen to reached 7% of final concentration at 4℃. After 3min of equilibration, the diluted semen was packed into 0.25ml straws and subjected to cryopreservation used freezing equipment. The packed straw were placed on height 5 cm above surface of liquid nitrogen(LN2) and held for 10min. After preserved for 2 weeks, the straw was thawed onto the 4℃ cooling bath. The images of motility and progressive motility spermatozoa were recorded by digital image recorder and analyzed by manual. The results showed 68.5% motility and 34.1% progressive motility in DMA/EKA diluent, 31.45% and 17.6% in glycerol/EKA, 45.4% and 8.6% in DMA/EKG, and 9.7% and 6.4% in glycerol/EKG. With these results, the alanyl glutamine and DMA could be used as a main composition of diluent and cryoprotectant for cryopreservation of chicken semen.
The turnip aphid is a worldwide pest, damaging mainly to crucifers. In order to understand the life parameters of Lipaphis erysimi for the eventual goal of control, the developmental periods, survival rates, lifespan, and fecundity of the species were investigated under five temperature regimes (15℃ - 35℃). Furthermore, the efficacy of several environment-friendly agricultural materials (EFAMs) that are on the market was subjected to test in order to obtain further accurate information. The developmental period of the turnip aphid nymph was longest at 15ºC as 16.9 days, shortened as temperature goes up to 25ºC (5.4 days), and then somewhat increased at 30ºC (5.9 days), suggesting that the most efficient temperature for nymphal development could be around 25ºC. Mortality of the nymphal turnip aphid was obvious at 35ºC, whereas it was minimal at other temperature schemes. The longevity of adults shortened as temperature goes up to 30ºC. In particular, the maximum lifespan for adults continued for 55 days at 15ºC, but shortened to 21 days at 30ºC. The total fecundity per day was 35.7 at 15ºC, 81 at 20ºC, 64.2 at 25ºC, and 6.6 individuals at 30ºC, showing the highest fecundity at 20ºC. After the turnip aphids were successfully stabilized in indoor environment the insecticidal activity was tested and mortality was determined 12, 24, 36, and 48 hrs after EFAMs are treated. Several on-the-market EFAMs showed more than 90% of insecticidal activity within 24 hrs or 48 hrs, but a few showed less than 90% activity, signifying importance of selection of proper EFAMs.
This study was conducted with the aim of evaluating the antibiotic effects of leaves, stems, and roots in yacon (Smallanthus sonchifolius). Antibacterial activity of leaf extract by disk diffusion method with Bacillus subtilis and Escherichia coli respectively showed 13.3 and 13.75mm diameters of clear zone. There was no significant difference between the stems and leaves. The minimum inhibitory concentration of leaves’ heating and agitation extraction showed a restrain of strain at 1mg/ml, but the stems and root extract did not appear. Yacon is a functional antibacterial material, and methanol extraction is more effective than water. This research was to investigate the growth stage of collection has the most effective antibacterial effects. It has collected yacon's leaves from June to October, which is an appropriate time for collection right before reaping. Yacon leaf has antibacterial effects on Bacillus subtilis, Escherichia coli, Enterococcus faecium, and Salmonella enteritifis. There were no significant differences by the growth stage of collection. Leaves collected in July are high in phenol which helps in sulfating activity works well considering the high scavenging capability of DPPH. Leaves collected in September are high in total flavonoid.
Background : According to medicinal plant standard culture, flower organ should be removed but there is no detail information on flower organ removal in Atractylodes macrocephala Koidzumi. This study was carried out to examine effect of flower organ removal on the increase of roots yield in Atractylodes macrocephala Koidzumi. Methods and Results : ○ Experiment variety : Atractylodes macrocephala Koidzumi. ○ Treatment : ① Flower organ non-cutting ② Flower organ cutting ○ Planting date : April, 2015/ April 25, 2016 ○ Planting distance : 30×20cm/ 30×15cm ○ Experiment place : Ginseng & Medicinal Plant Research Institute(Geumsan-gun, Chungcheongnam-do) Conclusion : The fresh rhizome yield of F. O. C. at a bud treatments were increased 21.0% ∼50.0% compare to F. O. N. C. treatments. The fresh rhizome yield of F. O. C. at a flower treatments were increased 17.4%∼34.6% compare to F. O. N. C. treatments. The fresh weight of above-ground parts of F. O. C. treatments were decreased 77.2%∼65.7% compare to F. O. N. C. treatments. F. O. C.(=Flower organ cutting) / F. O. N. C.(=Flower organ non-cutting).
Background : This study was carried out to understand the effect of seedling weight (SW) on growth and flowering in Panax ginseng. Methods and Results : The testing materials were Chunpoong (CP), Yunpoong (YP) and Jakyeongjong (JK). The increase of seedling (1yr) weight led to an increase in ratio of flowering plant and in number of flower per plant. The seed setting rate of two year-old plant (CP, YP, JK) increased with increase of SW at the planting time (PT) and number of flower per plant of three year-old plant (CP, YP) increased also. In the two year-old plant (JK), the ratio of three leaves per plant was 8.8, 19.6, 31.0, 42.0, 44.7 and 58.2%, respectively, in the SW of >0.6, 0.6~0.8, 0.8~1.0, 1.02~1.2, 1.2~1.4 and 1.4g<. The growth of ginseng plant was good with increase of SW at the PT. Conclusion : There was a highly positive correlation between seedling weight and flowering characteristics.
Background : Jiwhang (Rehmannia glutinosa L.) cultivation area of chungnam province was 62ha(219 farms, 53.9% of domestic cultivation area, M.A.F.R.A. 20142)). Recently, jiwhang is rapidly spread to 150ha ( Geumsan administration statistics, 2015) as taking place of income crop in Chungnam. High quality jiwhang GAP production and improvement of the distribution system including magnus customers, producer association fosterage and conventional market Vitalization were the reason of rapid cultivation area increase of Rehmannia glutinosa L. in Geumsan. This study was performed to set up the standard Rhizome size for planting in Rehmannia glutinosa L. Materials and Methods ○ Experiment variety : Togang ○ Treatment(rhizome length) : ① 1cm ② 2cm ③ 3cm ④ 4cm ⑤ 6cm(control) ○ Planting date : May 6, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : In the aboveground growth was no significant difference among treatments. In the root characteristics, there was no significant difference among treatments. Take a 1∼2cm rhizome planting saved rhizome amount and planting time to 73.8%∼64.3% and 68.4%∼ 57.8% respectively than 6cm(control).
Background : Generally, price of Jiwhang(Rehmannia glutinosa L.) is highest in August. In this study, Economic Evaluation and Productivity of 9 Jiwhang varieties w ere analyzed according to harvesting tim es of August and October. Materials and Methods ○ Experiment variety : Jiwhang 1, Korea jiwhang, Daegyung, Gogang, Togang, Dagang, Wongang, Hwanggang and Yeongang ○ Treatment : ①Initial-August harvest ②Mid-August harvest ③Ended-August harvest ④Ended-October harvest ○ Planting date : April 17, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : The higher roots yield at August harvest was in Gogang, Dagang and Togang. The lower roots yield at August harvest was in Korea jiwhang and Hwanggang. The higher economic feasibility at August harvest was in Gogang, Togang, Dagang and Wongang. The higher economic feasibility at ended-October harvest was in Gogang, Yeongang, Togang, Dagang and Wongang.
Background : According to medicinal plant standard culture, flower stalk should be removed at the stage of 4-5 main leaves appearance but there is no detail information on stalk removal in jiwhang (Rehmannia glutinosa L.). This study was carried out to examine effect of flower stalk removal on the increase of total yield in Rehmannia glutinosa L. Materials and Methods ○ Experiment variety : Korea jiwhang, Wongang ○ Treatment : ① Peduncle non-cutting ② Peduncle cutting ○ Planting date : April 18, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : Aerial part growth was no significant difference according to treatments in Wongang and aerial weight was havier in Peduncle cutting than in Peduncle non-cutting. Aerial part growth was no significant difference according to treatments in Korea jiwhang. The roots yield in Korea jiwhang was increased about 5.2% in Peduncle cutting. The roots yield in Wongang was increased about 24.9% in Peduncle cutting.
Background : Bai Zhu is generally harvested in 1-2 years after seedstock planting. Recently mainly in Guemsan, Bai Zhu is harvested in just 1 year after planting in spring . According to medicinal plant standard culture, Bai Zhu should be directly sown by 20cm distance in April. This study was carried out to find out proper planting date. Materials and Methods ○ Experiment variety : Bai Zhu (Atractylodes macrocephala Koidz.) ○ Treatment : Planting Date ① Late march ② Early april ③ Middle of april(control) ④ Late april Plantind density : ① 30×10cm ② ① 30×20cm ○ Planting type : Direct Seeding ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : Number of lateral branches in 30×10cm was more in late march than late April and aerial part growth was superior as planting date was earlier. Emergence rate was higher in middle of April and late April and aerial part weight, fresh root weight, dry root weight rate, and dry root weight were superior as planting date was earlier. Dry weight yield increased as 38.3% in late March compared to middle of April. Dry weight was havier as 36.2% in planting time of late March and early April than planting time of middle of April and late April. Total income was higher in planting time of late March and early April than planting time of middle of April and late April.
Background : Jiwhang (Rehmannia glutinosa L.) cultivation area of Chungnam province was 62ha (219 farms, 53.9% of domestic cultivation area, MAFRA. 20142)**). Recently, jiwhang is rapidly spread to 150ha (Geumsan administration statistics, 2015) as taking place of income crop in Chungnam. High quality jiwhang GAP production and improvement of the distribution system including magnus customers, producer association fosterage and conventional market vitalization were the reason of rapid cultivation area increase of Jiwhang in Geumsan. But low emergence rate caused by spring drought should be solved. This study was carried out to obtain basic data for emergence rate improvement in jiwhang. Materials and Methods ○ Experiment variety : Korea jiwhang ○ Treatment : ①Control ② 1 time irrigation at planting time ③1 time irrigation at planting time + transparent vinyl mulching ○ Planting date : April 30, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : There was no significant difference in the aboveground growth among treatments. The seedling emergence rate was higher in 1 time irrigation at planting time + transparent vinyl mulching(1ITVM) than control or 1 time irrigation at planting time(1I). Aerial part weight was significantly havier in 11ITVM than control or 1I. The roots yield was also more in 1ITVM than control or 1I. According to economic analysis, total income in 1ITVM compared to 1I and control was 125.1% and 54.0% higher respectively.
Background : For increasing saponin content of ginseng cultivated in shaded plastic house, this study was performed to investigate growth characteristics and saponin content of ginseng (Panax ginseng C.A. Mayer) according to foliar spray of germanium and water-soluble silicates processing. Methods and Results : Used a native species in this study is violet-stem variant that most commonly cultivated in ginseng’s farms. 1-year-old violet-stem variant was transplanted on March 24, 2015 and planting distance was 11 × 20 cm. Shading material of plastic house was used blue-white shading vinyl. The processing method of inorganic dissolved matter is as follows, we were diluted with germanium and water-soluble silicates to 500-fold, 1000-fold and investigated after foliar spray twice a month from May to September. The growth characteristics in above-ground part of 2-year-old ginseng was a good in the inorganic matters treatment compared to the control treatment, the difference of above-ground growth characteristics between the inorganic dissolved matters treatments was not significant. The growth characteristics in under-ground part of 2-year-old ginseng was a good in the inorganic matter treatments and root weight per plant in the 500-fold dilution of germanium was 12.4 g that increased by 29 % compared to the control (9.6 g). Crude saponin content of under-ground part was higher generally in inorganic matter treatments compared to the control (11.53 ㎎/g). In the 1000-fold dilution of water-soluble silicate and germanium (50:50), crude saponin content was the highest in 12.91 ㎎/g. Crude saponin content of above-ground part was higher generally in inorganic matter treatments compared to the control (61.76 ㎎/g). In the 1000-fold dilution of water-soluble silicate and germanium (50:50), crude saponin content was the highest in 65.69 ㎎/g. Conclusion : From the above results, we concluded that germanium and water-soluble silicates could be useful matters in promoting growth characteristics and saponin content of ginseng (Panax ginseng C.A. Mayer).
Background : This study was performed to set proper soil moisture tension for promoting seed emergence and yield of ginseng when direct seeding cultivation of ginseng was carried out in shaded plastic house. Methods and Results : The test cultivars were used Cheonpung, Yeonpung, Geumpung and seeds were sown on November 20, 2013. Irrigation starting point was set to 30, 40, 50 kPa and irrigation breakpoint was set to 20 kPa. Ginseng was cultivated in clay loam soil and shading material of plastic house were used blue-white shading vinyl. The emergence rate of 3-year-old ginseng cultivars in accordance with soil moisture tension indicated Cheonpung 97.0%, Yeonpung 95.0%, Geumpung 95.3% in each 50 kPa, 50 kPa, 30 kPa. In general, emergence rate of ginseng was higher tendency in 50 kPa (93.3∼97.0%). The average absolute soil moisture content during the growing season indicated a moisture content of 19.3% (30 kPa), 17.9% (40 kPa), 16.2% (50 kPa). Looking at the growth characteristics in above-ground part of 3-year-old ginseng cultivars according to soil moisture tension, Yeonpung, Cheonpung and Geumpung were good growth tendency in each 30kPa, 40kPa, 50kPa. On the other hand, looking at the growth characteristics in underground part of 3-year-old ginseng cultivars according to soil moisture tension, Cheonpung, Geumpung and Yeonpung were good growth tendency in each 30kPa, 40kPa, 50kPa. Yield per 10a was indicated that Yeonpung was the highest in the 50kPa to 456kg. Yield per 10a of Cheonpung and Geumpung indicated 347kg, 263kg in each 30kPa, 50kPa. Conclusion : From the above results, we concluded that ginseng(Panax ginseng C.A. Mayer) seems to be a difference of growth characteristics according to soil moisture tension. Therefore, it is need to manage soil moisture for each ginseng cultivars