The chemical composition of 86 species of native plants in Korea, including plants to be afforestation, was analyzed. The chemical composition of the species analyzed was different. The species with the highest extractable content was Viburnum dilatatum (3.91%), and the species with the lowest extractable content was Ligustrum lucidum (0.11%). The lignin content ranged from 12 to 39%, with an average of 25%. The species with the highest lignin content was Chaenomeles lagenaria (39.37%). Hemicellulose content ranged from 18 to 52%, with the highest species being Thuja occidentalis (51.22%) and Eucommia ulmoides (48.84%). Cellulose content ranged from 25 to 58%, and the species with the highest content were Prunus serrulata (57.67%), Diospyros kaki (57.14%), Aesculus turbinata (53.29%), Albizia julibrissin (53.02%), and Zelkova serrata (52.29%). The chemical composition was different for each use taxon of 86 plant species. The lignin content was the highest in the fruit group and the lowest in the group other than recommended species for afforestation. Cellulose content was highest in non-reforestation-recommended tree species and lowest in fruit trees. In classification according to tree height, lignin content was higher in shrubs than in tall trees, and cellulose content was highest in tall trees. Between deciduous and evergreen trees, the lignin content was high in deciduous trees (26.46%), and the cellulose content was also high in deciduous trees (44.01%). As a result of analyzing the correlation between each compound, there was a difference. There tended to be a positive correlation between extractives and lignin content. There was a negative correlation between extractives and holocellulose content, hemicellulose and cellulose. The higher extract content affected the cellulose content much more than hemicellulose. Also, the higher the lignin content, the lower the cellulose content. The species with low lignin content and high cellulose content were Diospyros kaki and Prunus serrulata var. spontanea. This result is expected to be primary data for bioenergy, pulp industry and bioindustry.

Currently, Japan is undertaking a nationwide project to measure and map radioactive contamination around Fukushima, as part of the efforts to restore normalcy following the nuclear accident. The Japan Atomic Energy Agency (JAEA) manages the Fukushima Environmental Safety Center, located approximately 20 km north of the Fukushima Daiichi nuclear power plant in Minamisōma City, Fukushima Prefecture. In collaboration with the JAEA, this study involved conducting comparison experiments and analyses with radiation detectors in high radiation environments, a challenging task in Korean environments. Environmental radiation surveys were conducted using three types of detectors: CZT, NaI(Tl), and LaBr3(Ce), across two contaminated areas. Dose rate values were converted using dose rate conversion factors for each detector type, and dose rate maps were subsequently created and compared. The detectors yielded similar results, demonstrating their feasibility and reliability in high radiation environments. The findings of this study are expected to be a crucial reference for enhancing the verification and supplementation of procedures and methods in future radiation measurements and mobile surveys in high-radiation environments, using these three types of radiation instruments.

Background: The flexible flatfoot is characterized by a flattening of the foot arch due to excessive bodyweight. The use of shoe insoles or taping methods has been identified as effective in realigning the navicular or calcaneus bones and addressing supination in pronated feet. Objects: This study aimed to analyze the difference between the arch taping attachment method, introduced in a previous study, and a novel taping method designed to provide support to the inner aspect of the heel bone in cases of flexible flatfoot. Methods: A navicular drop test was performed to discriminate flexible flatfoot. To analyze the differences in pressure distribution during walking for each taping method, the subjects underwent testing in the barefoot state with no attachments. The procedure included a sequence of arch taping and heel taping. Subsequent analysis of pressure distribution during walking utilized the GaitRite® system (GAITRite Gold, CIR Systems Inc.). Results: Arch taping and calcaneus taping significantly reduced the integrated pressure over time and peak pressure on the medial side of the midfoot for both feet compared to the barefoot state. Conclusion: The findings of this study suggest that supporting the inside of the heel through calcaneus taping, without direct stimulation to the longitudinal arch and navicular bone, is an effective intervention for flexible flatfoot.

Dry active wastes (DAWs) are combustible waste generated during the operation and decommissioning of nuclear facilities, and are known to be generated in the amount of approximately 10,000 to 40,000 drums (based on 200 L) per unit. It consists of various types of protective clothing, paper, and plastic bags, and is stored in radioactive waste storage facilities. Therefore, reducing the volume of DAWs is an important issue in order to reduce storage costs and utilize the limited space of waste storage facilities. Heat treatment such as incineration can dramatically reduce the volume of waste, but as the waste is thermally decomposed, CO2, a global warming gas, is generated and there is a risk of emissions of harmful gases including radionuclides. Therefore, a heat treatment process that minimizes the generation of CO2 and harmful gases is necessary. One of the alternatives to incineration is to carbonize DAWs, dispose of carbonized materials below the release standard as non-radioactive waste, and selectively separate and stabilize inorganic components, including radionuclides, from carbonized DAWs. In this study, 13 types of DAWs generated from nuclear power plants were selected and their thermal decomposition characteristics were investigated to design a heat treatment process that replaces incineration. As a result of TGA analysis, the temperature at which thermal decomposition of each waste begins is 260-300°C for cotton, 320-330°C for paper, 315-420°C for synthetic fiber, 350°C for latex gloves. The mass of most samples decreased to less than 1 % of the initial weight after heat treatment, and dust suit and latex gloves had residues of 13.83% and 13.71% of the initial mass, respectively. The metal components of the residue produced after heat treatment of the sample were analyzed by EDS. According to the EDS results, cotton contains Ca and Al, paper contains Ca, Al and Si, synthetic fiber contains Ca, Cu and Ti, latex gloves contain Ca and Mg. Additionally, ICP analysis was performed to quantify the inorganic components. These results are expected to be applicable to the processing of DAW generated at nuclear facilities in the future.

There is a large amount of radioactive waste in waste storage in the Korea Atomic Energy Research Institute. Some of the radioactive waste was generated during the dismantling process due to Korea Research Reactor 1&2 and it accounts for 20% of the total waste. Radioactive waste must be reduced by appropriate disposal methods to secure storage space and to reduce disposal costs. Research Reactor wastes include wastes that are below the acceptable criteria for selfdisposal and non-contaminated wastes, so they can be treated as wastes subject to self-disposal through contamination analysis and reclassification. In order to deregulation radioactive waste, it is necessary to meet the self-disposal standards stipulated in the Domestic Nuclear Act and the treatment standards of the Waste Management Act. The main factors of deregulation are surface contaminant, radionuclide activity and dose assessment. To confirm the contamination of waste, surface contaminant and gamma nuclide analysis were performed. After homogenizing the waste sample, it was placed in 1 L Mariinelli beaker. When collecting waste samples, 1 kg per 200 kg of waste was collected. The concentrations of the major radionuclides Co-60, Cs-134, Cs-137, Eu-152, and Eu-154 were analyzed using HPGe detector. To evaluate radiation dose, various computational programs were used. A dose assessment was performed with the analyzed nuclide concentration. The concentrations of representative nuclides satisfied the deregulation acceptance criteria and the results of the dose assessment corresponding to self-disposal method was also satisfied. Based on this results, KAERI submitted the report on waste self-disposal plan to obtain approval. After final approval, Research Reactor waste is to be incinerated and incineration ash is to be buried in the designated place. Some metallic waste has been recycled. In this study, the suitability of deregulation for self-disposal was confirmed through the evaluation of the surface contaminant analysis, radionuclide concentration analysis and dose assessment.

The HADES (High-level rAdiowaste Disposal Evaluation Simulator) was developed by the Nuclear Fuel Cycle & Nonproliferation (NFC) laboratory at Seoul National University (SNU), based on the MOOSE Framework developed by the Idaho National Laboratory (INL). As an application of the MOOSE Framework, the HADES incorporates not only basic MOOSE functions, such as multi-physics analysis using Finite Element Method (FEM) and various solvers, but also additional functions for estimating the performance assessment of Deep Geological Repositories (DGR). However, since the MOOSE Framework does not have complex mesh generation and data analyzing capabilities, the HADES has been developed to incorporate these missing functions. In this study, although the Gmsh, finite element mesh generation software, and Paraview, finite element analysis software, were used, other applications can be utilized as well. The objectives of HADES are as follows: (i) assessment of the performance of a Spent Nuclear Fuel (SNF) disposal system concerning Thermal-Hydraulic-Mechanical-Chemical (THMC) aspects; (ii) Evaluation of the integrity of the Engineered Barrier System (EBS) of both general and high-efficiency design perspective; (iii) Collaboration with other researchers to evaluate the disposal system using an open-source approach. To achieve these objectives, performance assessments of the various disposal systems and BMTs (BenchMark Test), conducted as part of the DECOVALEX projects, were studied regarding TH behavior. Additionally, integrity assessments of various DGR systems based on thermal criteria were carried out. According to the results, HADES showed very reasonable results, such as evolutions and distributions of temperature and degree of saturation, when compared to validated code such as TOUGH-FLAC, ROCMAS, and OGS (OpenGeoSys). The calculated data are within the range of estimated results from existed code. Furthermore, the first version of the code, which can estimate the TH behavior, has been prepared to share the contents using Git software, a free and open-source distribution system.

The effect of the surrounding vegetation on the seed germination and growth of mountain-cultivated ginseng (MCG, Panax ginseng C.A. Meyer) was investigated. Seed germination rate and growth were tested for allelopathy effects on four forest tree species after treatment with fallen leaves and leaf extracts. In the case of soil treatment through fallen leaves and crushed leaves, the germination rate was lower in the Quercus myrsinifolia treatments, and the average germination time was slower when Chamaecyparis obtusa was treated. In the case of Pinus densiflora and Quercus variabilis, which are used in most of the MCG cultivation areas, they did not have a significant effect on seed germination. In the fallen leaves treatments, the stem showed a tendency to lengthen. The hot water extract treatment showed a higher germination percentage than the cold water extract treatment. The extract treatment showed a deficient germination percentage of some MCG seeds. However, in the case of the treatments except for this, the germination percentage was similar to that of the control treatment. However, the Mean Germination Time, germination rate, and germination value were faster and higher than the control treatment. As a result of calculating the allelopathic index (AI) of MCG according to the extract treatment of 4 species, most had a negative effect on germination, and P. densiflora and Q. variabilis extracts showed the most significant effect. The ginsenoside content was higher in the fallen leaves treatment than in the control. The above results will help select and manage MCG plantations.

To improve the quality of jujube (Zizyphus jujuba Miller var. hoonensis), which is a fruit of health functional, the effect of polyphenol preparation treatment on the fruit characteristics of two cultivars (cv. Bokjo and cv. Sangwang) of jujube was investigated. There was no difference in the height and breast diameter of jujubes tested between the polyphenol treatments and non treatment. Jujube trees treated with polyphenol preparation produced significantly more fruit than untreated in both cultivars. In cvultivar of Bokjo, the polyphenol preparation treatment increased the fruit's fresh weight and dry weight more than two times, respectively, compared to the untreated treatment. Polyphenol preparation tr eatments also changed the leaf characteristics of jujube trees. In the polyphenol-treated trees, leaf thickness tended to be thickest at the top and thinnest at the bottom. Polyphenol preparation treated jujube trees showed no difference in chlorophyll content. Moisture content was slightly higher in the untreatment than in the treatments. Visually, the polyphenol preparation treatment had a dark green color. Jujubes treated with polyphenol preparations showed differences in polyphenol content in fruits. The polyphenol content in both peel and flesh of the treatments were much higher than that of the untreatment. Reducing sugar was contained more in the peel than in the flesh and was higher in the untreatment than in the polyphenol preparation treatments. Treatment with polyphenol preparation showed differences in fruit appearance. As described above, it was found that the treatment of polyphenol preparation changed the leaves, fruit shapes and components of jujube trees. In particular, jujubes treated with polyphenol preparations are expected to contribute significantly to eco-friendly and highly functional jujube cultivation, as they appear to produce many fruits and increase the content of polyphenols and sugars.

Corrosion-related challenges remain a significant research topic in developing next-generation Molten Salt Reactors (MSRs). To gain a deeper understanding of preventing corrosion in MSRs, previous studies have attempted to improve the corrosion resistance of structural alloys by coating surfaces such as alumina coating. To conduct a corrosion test of coating alloys fully immersed in molten salt, it’s important to ensure that the coating application process is carefully carried out. Ideally, coating all sides of the alloy is necessary to avoid gaps like corners of the alloy, while only applying a one-sided coating alloy can lead to galvanic corrosion with the base metals. Using the droplet shape of eutectic salt applied to only one side of the coating alloy would avoid these problems in conventional corrosion immersion tests, as corrosion would occur solely on the coating surface. Although the droplet method for corrosion tests cannot fully replicate corrosion in the MSRs environment, it offers a valuable tool for comparing and evaluating the corrosion resistance of different coating surfaces of alloys. However, the surface area is important due to the effect of diffusion in the corrosion of alloy in molten salt environments, but it is difficult to unify in the case of droplet tests. Therefore, understanding the droplet-alloy properties and corrosion mechanism is needed to accurately predict and analyze these test systems’ behavior highlighting unity for corrosion tests of different coating surfaces of alloys. To analyze the molten salt droplet behavior on various samples, pelletized eutectic NaCl-MgCl2 was prepared as salt and W-, Mo-coating, and base SS316 as samples. At room temperature, the same mass of pelletized eutectic NaCl-MgCl2 was placed on different samples under an argon atmosphere and heated to a eutectic point of 500°C in a furnace. After every hour, the molten droplets were hardened by rapid cooling at room temperature outside the furnace. The mass loss of salts and the contact area of the samples were measured by mass balance and SEM. The shape, surface area to volume ratio, and evaporation of the droplets of NaCl-MgCl2 per each coating sample and hour were analyzed to identify the optimal mass to equalize the contact coating surface of alloys with salts. Furthermore, We also analyzed whether their results reached saturation of corrosion products through ICP-MS. This will be significant research for the uniformity of the liquid-drop shape corrosion test of the coating sample in molten eutectic salts.

Molten salt reactors have several advantages over conventional light water reactors. These include producing less nuclear waste, operating at higher power efficiency and inherent safety due to the low operating pressure. NaCl-MgCl2 eutectic salt is one of the candidates for the molten salt reactor coolant. However, because the salt is very hygroscopic, structural material corrosion occurs resulting in the high cost to maintain. To mitigate corrosion there have been many studies for the dehydration of the salt, especially focusing on the magnesium chloride. The reason is that the moisture adsorbed to the magnesium chloride undergoes hydrolysis over 200 degrees Celsius and decomposes to MgOHCl while the moisture associated with the NaCl is easily liberated during the heating procedure without chemical reaction. As the operating temperature of the molten salt is between 500 and 700 degrees Celsius, the MgOHCl is believed as the main cause for the structural corrosion. In this research, thermal dehydration of the salt with elemental Mg, for the NaCl-MgCl2 eutectic, was studied based on the previous dehydration methods and considering scalable and easy to handle. The MgOHCl was removed both through the thermal decomposition and the reduction by Mg metal. After the removal of MgOHCl, based on the difference between the freezing points and the density, the salt cooled down very slowly to ensure the separation between the purified salt and the disposals such as MgO and remaining Mg metals. The efficiency of the dehydration method was determined by the concentration of the MgOHCl. The concentration was determined by cyclic voltammetry and the result was compared with undehydrated salt and salt dehydrated thermally without the addition of Mg metal. To qualify and quantify the MgOHCl content through the cyclic voltammetry, it was necessary to observe the signal by adding MgOHCl to each sample. Based on the thermogravimetric analysis result of MgCl2· 6H2O, MgOHCl powder was formed through heating the MgCl2·6H2O.

Chemical environments of near-field (Engineered barrier and surrounded host rock) can influence performance of a deep geological repository. The chemical environments of near-field change as time evolves eventually reaching a steady state. During the construction of a deep geological repository, O2 will be introduced to the deep geological repository. The O2 can cause corrosion of Cu canisters, and it is important predicting remaining O2 concentration in the near-field. The remaining O2 concentration in the near field can be governed by the following two reactions: oxidation of Cu(I) from oxidation of Cu and oxidation of pyrite in bentonite and backfill materials. These oxidation reactions (Cu(I) and pyrite oxidation) can influence the performance of the deep geological repository in two ways; the first way is consuming oxidizing agents (O2) and the second way is the changing pH in the near-field and ultimately influencing on the mass transport rate of radionuclides from spent nuclear fuel (failure of canisters) to out of the engineered barrier. Hence, it is very important to know the evolution of chemical environments of near-field by the oxidation of pyrite and Cu. However, the oxidation kinetics of pyrite and Cu are different in the order of 1E7 which means the overall kinetics cannot be fully considered in the deep geological repository. Therefore, it is important to develop a simplified Cu and pyrite oxidation kinetics model based on deep geological repository conditions. Herein, eight oxidation reactions for the chemical species Cu(I) were considered to extract a simplified kinetic equation. Also, a simplified kinetics equation was used for pyrite oxidation. For future analysis, simplified chemical reactions should be combined with a Multiphysics Cu corrosion model to predict the overall lifetime of Cu canisters.