We have performed an experiment to evaluate the efficacy of salt and hot water treatments in soil for managing situations where high-risk plant-parasitic nematodes (PPNs) are detected in farms and flower shops that cultivate foliage plants. The density of Pratylenchus penetrans was reduced by 100% with salt treatments of 20 and 40 kg m-2, while decreases of 95% and 99.8% were observed with treatments of 5 and 10 kg m-2, respectively. In the hot water treatment, Pratylenchus penetrans decreased by 97.6% compared to the initial density. The salt treatment resulted in a decrease in pH and an increase in electrical conductivity (EC) compared to untreated soil. However, other characteristics, including organic matter content, available phosphorus, total nitrogen (T-N) rate, and exchangeable cations, did not differ from the control. In the case of hot water treatment, all properties were similar to those in the untreated group. As a result of this study, salt applications of more than 20 kg m-2 and hot water at 96°C could serve as effective control methods when high-risk PPNs are detected in flower shops and greenhouses located in urban or near-urban areas.

Current investigations provide a comprehensive understanding of the occurrence and biodiversity of plant-parasitic nematodes (PPNs) in the major citrusproducing regions of Jeju Island, South Korea. Our survey identified five genera and five species of PPNs from 82 infested Citrus unshiu field samples collected across 116 sites in the Jeju provinces. Community analysis revealed the highest prevalence of PPNs (39.02%) at Namwon-eup, significantly driven by Tylenchulus semipenetrans, followed by Paratylenchus sp., Helicotylenchus sp., Meloidogyne sp., and Pratylenchus sp. Data indicate that all 82 sites were infested with T. semipenetrans (70.68%), marking a considerable increase in prevalence compared to previous surveys and posing a significant threat to citrus cultivation. The study results also demonstrate the influence of soil type on PPNs communities, revealing correlations between soil texture and nematode diversity. Citrus orchards cultivated in black clay loam soil exhibited significant PPN infestations. Overall, the PPN survey underscores the economic importance of monitoring citrus nematode infection rates and maintaining economic threshold levels in citrus production. It also emphasizes the need for developing effective management strategies to control PPNs, which are essential for maintaining crop yield and ensuring agricultural sustainability.

Soybean (Glycine max L.) is one of the most important food crops in Korea and a crucial source of protein. However, soybean production is significantly impacted by various plant pathogens, including insect pests, plant-parasitic fungi, bacteria, and nematodes. The soybean cyst nematode (SCN), Heterodera glycines, is a major plant-parasitic nematode that causes an estimated annual loss of US$29 million in Korean soybean industry. Cultivating SCN-resistant soybean cultivars is considered the most effective method for managing this nematode. To identify such cultivars, we conducted resistance screening tests for 32 soybean cultivars. No resistant cultivar was found. Daewang cultivar exhibited moderate resistance to SCN, while the other 31 were susceptible. These findings suggest that Daewang is currently the best choice for fields infested with SCN. There is a critical need for developing SCN-resistant soybean cultivars in Korea.

To non-destructively determine the burnup of a spent nuclear fuel assembly, it is essential to analyze the nuclear isotopes present in the assembly and detect the neutrons and gamma rays emitted from these isotopes. Specifically, gamma-ray measurement methods can utilize a single radiation measurement value of 137Cs or measure based on the energy peak ratio of Cs isotopes such as 134Cs/137Cs and 154Eu/137Cs. In this study, we validated the extent to which the results of gamma-ray measurements using cadmium zinc telluride (CZT) sensors based on 137Cs could be accurately simulated by implementing identical conditions on MCNP. To simulate measurement scenarios using a lead collimator, we propose equations that represent radiation behavior that reaches the detector by assuming “Direct hit” and “Penetration with attenuation” situations. The results obtained from MCNP confirmed an increase in measurement efficiency by 0.47 times when using the CZT detector, demonstrating the efficacy of the measurement system.

Recently, the spent fuel pools withdrawn from nuclear power plants in Korea have been saturated. Therefore, specific regulations on the management of spent fuel pools, such as transportation and intermediate storage are needed. The burnup history is directly related to the management of spent nuclear fuel. This is because the decision to handle nuclear fuel may vary depending on the initial concentration of nuclear fuel, the degree to which nuclear fuel is irradiated and radioisotope nuclides are decayed, and the cooling state in the spent nuclear fuel storage tank. The purpose of this study is to determine the burnup of fuel based on the value obtained by scanning the surface of spent nuclear fuel through a neutron detector. Conversely, a database of neutron signals that scan bundles of spent nuclear fuel with an instrument with an already identified combustion history needs to be completed. First of all, the correlation between burnup history and nuclides was identified in previous studies. By setting the burnup history as the input value in the ORIGEN-ARP code, it was possible to identify the radioactive isotopes remaining in the bundle of nuclear fuel. Neutrons can finally be measured based on the amount of nuclide inventory that constitutes spent nuclear fuel. Through MCNP, the neutron detector was simulated and signals were measured to confirm how it correlates with the previously acquired burnup history database. In addition, the M (sub-critical multiplication) value, which is essential for neutron measurement, was checked to confirm the degree to which additional neutrons were generated in spent nuclear fuel in a subcritical state. The target nuclear fuel assembly was CE16×16, WH14×14, and WH17×17, which confirmed the correlation (1) between burnup, enrichment, and cooling time with the previous research topic, TNSI (Total neutron source intensity). 􀜤􀜷􁈺􀜩􀜹􀝀/􀜯􀜶􀜷􁈻 = 0.83􁈺􀜵􀯇􁈻􀬴.􀬶􀬷􀬼 ∙ 􁈺􀜫􀜧􁈻􀬴.􀬸􀬺􀬶􀬻 ∙ 􀝁􀬴.􀬴􀬴􀬼􀬷∙􀯧 􁈺1􁈻 A neutron signal will be obtained from the case according to each burnup history constituting this database. In particular, PAR=SF, a function that calculates the production amount of the fission product, was used. To confirm the computational logic of SF, it was confirmed whether a reasonable calculation was made by calculating with a nuclide spectrum.

The management before disposal of spent nuclear fuel is an essential process for safe management. It is important to determine the amount of nuclide inventory in order to ensure the integrity of spent nuclear fuel, as radiation generated from the nuclides is generated along with residual heat in the spent nuclear fuel. Based on the data on the characteristics of spent nuclear fuel generated in Korea, the correlation equation between burnup and enrichment was derived by referring to overseas cases (Sweden). Source term analysis was performed using the SCALE ORIGEN ARP code by securing the burnup history of nuclear fuel. Calculation was performed by inputting the combustion history of the fuel WH14×14 and WH17×17 as a reference for CE16×16 spent fuel. Through this study, the relationship was identified using the burnup, enrichment, and cooling time factors that influence the characteristics of spent nuclear fuel. In addition, the total source and spectrum data from neutrons and gamma sources were used to find out the characteristics of fuel.

As the number of nuclear power plants whose design life has expired worldwide increases, the attempts are continuing to complete the project of nuclear back-end cycle, the last task of the nuclear industry. Decontamination is essential in the process of dismantling nuclear facilities and restoration sites to remove all or some of the regulatory controls from an authorized facility. Among radioactive wastes, particularly contaminated soil is characterized by difficult physical decontamination because radionuclides are adsorbed between soil particles, that is, pores. Therefore, chemical decontamination is mainly used, which has the disadvantage of generating a lot of secondary waste. In order to overcome these disadvantages, an eco-friendly soil decontamination process is being developed that can drastically reduce the amount of secondary waste generated by using supercritical carbon dioxide. Supercritical carbon dioxide can easily control its physical properties and has both liquid and gas properties. However, since supercritical carbon dioxide is non-polar, additives are needed to extract polar metal ions, which are the goal of decontamination. Therefore, ligand with both CO2-philic and metal binding regions was selected. In previous studies, the decontamination efficiency of soil was evaluated by reacting contaminated soil with solid ligand and co-ligand at once. When solid ligands were used, the decontamination efficiency was lower than expected, which was expected because chemical substances were somewhat difficult to exchange in the closed process. In this study, in order to increase the efficiency of the decontamination process, the need for a process of liquefying ligand and continuously flowing it has been raised. Therefore, a co-solvent that dissolves well at the same time in SCCO2, ligand, and co-ligand was selected. In the selection process, a total of eight substances were selected by dividing into six polar substances and two non-polar substances through various criteria such as economic feasibility, eco-friendliness, and harmlessness. Thereafter, ethanol was finally selected through solubility evaluation for SCCO2 and additives. It is expected that a more effective decontamination process can be constructed when the additive is liquefied using a solvent selected from the results of this study.