Nuclear facilities present the important task related to the migration and retention of radioactive contaminants such as cesium (Cs), strontium (Sr), and cobalt (Co) for unexpected events in various environmental conditions. The distribution coefficient (Kd) is important factor for understanding these contaminants mobility, influenced by environmental variables. This study focusses the prediction of Kd values for radionuclides within solid phase groups through the application of machine-learning models trained on experimental data and open source data from Japan atomic energy agency. Three machine-learning models, such as the convolutional neural network, artificial neural network, and random forest, were trained for prediction model of the distribution coefficient (Kd). Fourteen input variables drawn from the database and experimental data, including parameters such as initial concentration, solid-phase characteristics, and solution conditions, served as the basis for model training. To enhance model performance, these variables underwent preprocessing steps involving normalization and log transformation. The performances of the models were evaluated using the coefficient of determination. These results showed that the environmental media, initial radionuclide concentration, solid phase properties, and solution conditions were significant variables for Kd prediction. These models accurately predict Kd values for different environmental conditions and can assess the environmental risk by analyzing the behavior of radionuclides in solid phase groups. The results of this study can improve safety analyses and longterm risk assessments related to waste disposal and prevent potential hazards and sources of contamination in the surrounding environment.

Radionuclides in low- and intermediate-level radioactive wastes from the decommissioning process of nuclear power plants were generally immobilized by cementation methods. Ethylenediaminetetraacetic acid (EDTA), which is extensively used as a decontamination agent, can affect the behaviors of radionuclides immobilized in cement waste forms. In this study, the effects of EDTA contained in simulated radioactive decommissioning wastes on the leaching characteristics of immobilized Co and Cs and the microstructure evolution of cement waste form. Co leaching was accelerated by the formation of Co–EDTA complexes with high mobility and solubility. Cs leaching was hindered by the ion competition with other metal–EDTA complexes for releasing from the cement waste form. Cs leaching was also retarded by carbonated layer at edge of the cement waste form, which process is facilitated by the presence of EDTA. Finally, the effects of EDTA on the leaching characteristics of immobilized Cs and Co and the microstructure evolution of the cement waste form should be considered to ensure the safety of disposal for lowand intermediate-level radioactive wastes.

Structural stability of a waste form can be provided by the waste form itself (steel components, etc.), by processing the waste to a stable form (solidification, etc.), or by emplacing the waste in a container or structure that provides stability (HICs or engineered structure, etc.). The waste or container should be resistant to degradation caused by radiation effects. In accordance with the requirements for the domestic waste acceptance criteria, irradiation testing of solidified waste forms containing spent resin should be conducted on specimens exposed to a dose of 1.0E+6 Gy and other material 1.0E+7 Gy. Expected cumulative dose over 300 years is about 1.770E+6 Gy for spent resin and 0.770E+6 Gy for dried concentrated waste generated from NPPs generally. According to NRC Waste Form Technical Position, to ensure that spent resins will not undergo adverse degradation effects from radiation, resins should not be generated having loadings that will produce greater than 1E+6 Gy total accumulated dose. If it necessary to load resins higher than 1E+6 Gy, it should be demonstrated that the resin will not undergo radiation degradation at the proposed higher loading. This is the recommended maximum activity level for organic resins based on evidence that while a measurable amount of damage to the resin will occur at 1E+6 Gy, the amount of damage will have negligible effect on disposal site safety. Cementitious materials are not affected by gamma radiation to in excess of 1E+6 Gy. Therefore, for cement-stabilized waste forms, irradiation qualification testing need not be conducted unless the waste forms contain spent resins or other organic media or the expected cumulative dose on waste forms containing other materials is greater than 1E+7 Gy. Testing should be performed on specimens exposed to IE+6 Gy or the expected maximum dose greater than 1E+6 Gy for waste forms that contain ion exchange resins or other organic media or the expected maximum dose greater than 1E+7 Gy for other waste forms. This is suggestion as a review result that requirement for irradiation testing of solidified waste forms has something to be revise in detail and definitively.

The permanent disposal of discharged spent nuclear fuel (SNF) and contaminated radioactive waste generated from the subsequent chemical treatments of SNF has become a serious pending issue in many countries that operate the nuclear power plants. Among the diverse engineering solutions proposed for the disposal of high-level radioactive waste (HLW), deep geological disposal (DGD) has been considered as the most proven and safe option to prevent any significant release of radionuclides into the biosphere and to predictably ensure the long-term performance of disposal system. The DGD system consists of multiple structural components; the bentonite clay-based buffer and tunnel backfills are designed to perform the primary hydrogeochemical functions of 1) inhibiting the ingress of groundwater and reactive substances that could compromise the integrity of canister and 2) retarding the migration of released radionuclides into biosphere by providing the sufficient chemisorption sites. Montmorillonite, which is a 2:1 phyllosilicate mineral belonging to smectite group, constitutes the majority of bentonite, and it mainly predominate the swelling and chemisorption capacities of the clay material. Thus, it is essentially required to thoroughly understand the chemical interactions of major radionuclides and other important substances with montmorillonite in advance to accurately evaluate the long-term retention performance of engineered barriers and to reduce the uncertainties in the safety assessment of a deep geological repository (DGR) ultimately. Thus far, sorption of dissolved species onto mineral adsorbents has been generally described and quantified using the simple sorption-desorption distribution coefficient (Kd) concept; since any specific reaction mechanisms are not considered and reflected in the Kd concept, an empirical Kd value is intrinsically dependent on the aqueous conditions under which it was measured. In this framework, substantial scientific efforts have been made to develop a robust basis for geochemically parametrizing the sorption phenomena more reliably, and the application of thermodynamic sorption modeling (TSM), which is based on the chemical principle of mass action laws, has been studied with the aim of improving overall confidence in the description of radionuclide migration under a wide range of aquatic conditions. The disposal performance demonstration R&D division of KAERI introduced a new reference Ca-bentonite clay called Bentonil-WRK (Clariant Korea) for HLW disposal research in 2021 as the domestic Ca-bentonite sources have being depleted. We successfully separated and purified Ca-montmorillonite from the Bentonil-WRK clay, and its geochemical characteristics were meticulously studied by means of XRD, BET, CEC, FT-IR analyses and controlled acid-base titration. In this work, chemical sorption behaviors of aqueous iodide and benzoate, which are a major fission product in HLW and a model ligand of complex natural organic matters present in the deep geological environment, onto the purified Camontmorillonite were assessed under ambient conditions of S/L = 5 g/L, I = 0.01 M CaCl2, pH = 4- 9, pCO2 = 10-3.4 atm, and T = 25°C. Further, their unique adsorption envelopes and corresponding thermodynamic reaction constants refined from the diffuse double layer model (DDLM)-based inverse modeling of experimental sorption data were discussed.

Spent nuclear fuel management is a high-priority issue in South Korea, and addressing it is crucial for the country’s long-term energy sustainability. The KORAD (Korea Radioactive Waste Agency) is leading a comprehensive, long-term project to develop a safe and effective deep geological repository for spent nuclear fuel disposal. Within this framework, we have three primary objectives in this work. First, we conducted statistical analysis to assess the inventory of spent nuclear fuel in South Korea as of 2021. We also projected future generation rates of spent nuclear fuels to identify what we refer to as reference spent nuclear fuels. These reference spent nuclear fuels will be used as the design basis spent fuels for evaluating the safety of the repository. Specifically, we identified four types of design basis reference spent nuclear fuels: high and low burnup from PLUS7 (with a 16×16 array) and ACE7 (with a 17×17 array) assemblies. Second, we analyzed radioactive nuclides’ inventory, activities, and decay heats, extending up to a million years after reactor discharge for these reference spent nuclear fuels. This analysis was performed using SCALE/TRITON to generate the burnup libraries and SCALE/ORIGEN for source term evaluation. Third, to assess the safety resulted from potential radioactive nuclides’ release from the disposal canister in future work, we selected safety-related radionuclides based on the ALI (Annual Limit of Intake) specified in Annex 3 of the 2019-10 notification by the NSSC (Nuclear Safety and Security Commission). Conservative assumptions were made regarding annual water intake by humans, canister design lifetime, and aquifer flow rates. A safety margin of 10-3 of the ALI was applied. We selected 56 radionuclides that exceed the intake limits and have half-lives longer than one year as the safety-related radionuclides. However, it is crucial to note that our selection criteria focused on ALI and half-lives. It did not include other essential factors such as solubility limits, distribution coefficients, and leakage processes. So, some of these nuclides can be removed in a specific analysis area depending on their properties.

Spent nuclear fuels (SNFs) are stored in nuclear power plants for a certain period of time and then transported to an interim storage facility. After that, SNFs are finally repackaged in a disposal canister at an encapsulation plant for final disposal. Finland and Sweden have already completed the design of the spent nuclear fuel encapsulation plant. In particular, Finland has begun the construction of the encapsulation plant and is on the verge of completion. Korea Radioactive Waste Agency (KORAD) is conducting a conceptual design of a deep geological repository for SNFs. Conceptual design of the encapsulation plant is part of the research activity. It is highly required to draft an operation process of the encapsulation plant before an actual design activity. As part of the activity, Finnish design concept of the encapsulation plant and experience were thoroughly reviewed. Finally a preliminary concept of the operation process was proposed considering Korean unique situations such as the volume of SNFs estimated to be disposed of, types of transportation cask and other considerations.

In this work, norepinephrine (NE) was determined by an electrochemical sensor represented by a carbon paste electrode boosted using nitrogen-doped porous carbon (NDPC) derived from Spirulina Platensis microalga anchored CoFe2O4@ NiO and 1-Ethyl-3-methylimidazolium acetate (EMIM Ac) ionic liquid. The morphological characteristics of the catalyst were recorded by field emission scanning electron microscope (FE-SEM) images. Moreover, the electrochemical behavior of norepinephrine on the fabricated electrode was checked using various voltammetric methods. All tests were done at pH 7.0 as the optimized condition in phosphate buffer solution. The results from linear sweep voltammetry revealed that the electro-oxidation of norepinephrine was diffusion, and the diffusion coefficient value was obtained by chronoamperometry (D⁓6.195 × 10– 4). The linear concentration of the modified electrode was obtained from 10 to 500 μM with a limit of detection of 2.26 μM using the square wave voltammetry (SWV) method. The sensor selectivity was investigated using various species, and the results from stability and reproducibility tests showed acceptable values. The sensor's efficiency was tested in urine and pharmaceutical as real samples with recovery percentages between 97.1% and 102.82%.

We produced an activated carbon using sodium-lignosulfonate, in which we investigated how the sodium salt in lignin served as the activating agent during heat treatment. Our process resulted in a product with a high specific surface area of 1324 m2/ g at 800 °C and microporous structure. During the activation process, we observed the consumption of carbon due to the dehydration reaction of NaOH and the reduction of Na2CO3 to metallic Na, which created pores through oxidation/ reduction reactions. The intercalation of metallic Na between the lattices at high temperatures formed additional pores and increased the specific surface area. Our proposed mechanism holds promise for enhancing the control of the microstructure and porosity of activated carbons through the thermal treatment of biomass.

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.

PURPOSES : The evaluation of the low-temperature performance of an asphalt mixture is crucial for mitigating transverse thermal cracking and preventing traffic accidents on expressways. Engineers in pavement agencies must identify and verify the pavement sections that require urgent management. In early 2000, the research division of the Korea Expressway Corporation developed a three-dimensional (3D) pavement condition monitoring profiler vehicle (3DPM) and an advanced infographic (AIG) highway pavement management system computer program. Owing to these efforts, the management of the entire expressway network has become more precise, effective, and efficient. However, current 3DPM and AIG technologies focus only on the pavement surface and not on the entire pavement layer. Over the years, along with monitoring, further strengthening and verification of the feasibility of current 3DPM and AIG technologies by performing extensive mechanical tests and data analyses have been recommended. METHODS : First, the pavement section that required urgent care was selected using the 3DPM and AIG approaches. Second, asphalt mixture cores were acquired from the specified section, and a low-temperature fracture test, semi- circular bending (SCB) test, was performed. The mechanical parameters, energy-release rate, and fracture toughness were computed and compared. RESULTS : As expected, the asphalt mixture cores acquired from the specified pavement section ( poor condition – bad section) exhibited negative fracture performances compared to the control section (good section). CONCLUSIONS : The current 3DPM and AIG approaches in KEC can successfully evaluate and analyze selected pavement conditions. However, more extensive experimental studies and mathematical analyses are required to further strengthen and upgrade current pavement analysis approaches.

The striped fruit fly, Zeugodacus scutellata., is ubiquitous in agricultural areas, making it a critical pest to monitor and manage. It is necessary to develop a technique for rearing Z. scutellata in the laboratory to achieve mass production for biological control. The pumpkin is an important host plant for Z. scutellata; females lay their eggs on the tops of pumpkin flower buds, and larvae consume the stamens from top to bottom before dropping to the ground. Several types of diets are considered in the present study, including liquid, solid, and semisolid diets. Methyl benzoate, propionic acid, sodium benzoate, and citric acid were tested for their ability to suppress microbial contamination and improve the shelf life of diets. Fresh pumpkin, pumpkin flower, and pumpkin powder were used as primary ingredient. Reared adults were tested for their egg laying and survival abilities based on different diets. Approximately 86% of adults emerged from liquid and semisolid diets. Solid diets reduce pupae production and adult emergence. The diets with a total viability of less than 75% were discarded, which is considered as a reasonable threshold to determine whether a diet is nutritionally sufficient to rear the flies. Based on the results of the present study, we have developed a diet for mass rearing in laboratories, which may assist in providing a scientific basis for the effective control of Z. scutellata.

본 연구는 주변 환경의 차이에 따른 화분매개곤충의 유입 특성을 파악하기 위하여 국립수목원 내 진화속을걷 는정원과 부추속전문전시원에 식재된 울릉산마늘의 화분매개곤충을 조사하였다. 2023년 5월 22일부터 6월 2일 까지 꽃이 70% 이상 개화하였을 때 포충망을 활용하여 8일간 곤충을 채집하였고, 각 전시원 별 식생(피도), 기후 (온도·습도·조도)를 조사하였다. 조사 결과 진화속을걷는정원에서 피도 60% 온도 26.4℃, 습도 31.5%, 조도 40953.6lx, 화분매개곤충 20과 450개체, 부추속전문전시원은 피도 90%, 온도 25.6℃, 습도 31.6%, 조도 6387lx, 화분매개곤충 15과 196개체로 나타났다. 온도와 조도가 상대적으로 높은 진화속을걷는정원이 채집된 곤충의 다양성과 방문 빈도가 높았다. 시간대별 곤충의 방문 빈도를 비교해본 결과 온도와 조도는 개체수가 증가할 때 같이 증가하는 경향을 보였으며, 습도는 반대의 경향을 보였다.

곤충병원성 선충인 Heterorhabditis. megidis(큰형광병원선충)는 참나무 군락지(광주광역시 소재) 사양토에 서 분리 동정되었고, 곤충병원성을 가지는 공생세균은 Photorhabdus temperata로 분리 동정되어 각각 GJ1-2로 명명하였다. H. megidis GJ1-2는 고추(녹광), 애호박(농우), 오이(백다다기), 참외(금싸라기), 토마토(베타티니) 유묘기 경엽처리와 배추(씨알천하일품), 상추(진청맛), 완두(청진주), 수박(삼복꿀), 무(서호) 유묘기 관주처리 에서 21일차까지 기준량과 배량에 대하여 약해(약해 판정기준결과: 0)가 나타나지 않았다, H. megidis GJ1-2는 배추 파밤나방에 대한 방제 효과는 이천시(경기도 소재)와 수원시(경기도 소재)의 시설재배 포장에서 각각 경엽 처리 3일차 71.8%. 73.9%, 7일차 86.2%, 84.6%로 나타났으며, 옥수수 열대거세미나방에 대한 방제 효과는 제주시 (제주특별자치도 소재)의 노지(미사질 양토)에서 경엽처리 7일차 82.6%로 나타났다. 그리고 H. megidis GJ1-2는 랫드를 이용한 급성경구와 급성경피 독성시험 반수치사농도(LD50) 값은 2,000 mg/kg B.W 초과로 IV급(저독성) 으로 구분되었고, 토끼를 이용한 피부와 안점막에 자극성이 없는 것으로 구분되었다. 그리고 담수어류(송사리) 에 대한 급성독성시험 반수치사농도(LD50) 값은 영향을 미치지 않는 기초시험농도 100 mg/L를 초과하였다.

The occurrence status of eggs and adults of Pochazia shantungensis, Lycorma delicatula, and Lymantria dispar was investigated in the Chungcheongbuk-do region. The results showed that the overwintering eggs of P. shantungensis occurred in 24.2% of the region in 2021 and 22.1% in 2022, while adults occurred in 25.2% in 2021 and 24.3% in 2022, indicating the highest occurrence among the pests studies in this research. The occurrence of overwintering eggs of L. delicatula was relatively low, with 2.6% of the region affected in 2021 and 1.9% in 2022. Adults of L.delicatula occurred in 3.2% of the region in 2021 and 3.6% in 2022, while they were not undiscovered in Jeungpyeong, Jincheon, Goesan, and Danyang areas. Their area of occurrence was less than 3% of the region, and the volume of occurrence was not very large. Overwintering eggs of L.dispar occurred in 4.1% of the area in 2021 and 1.7% in 2022, showing a decreasing tendency compared to the previous year, and their occurrence was only low to middle in terms of the degree of occurrence.

Sweet pepper(paprika) belongs to the genus Capsicum, and is one of the most important export product from Korea to Japan and Southeast Asia. So it is important to eradicate plant quarantine pests before export sweet pepper. Aphids, whiteflies and mites are major pests that can damage to sweet peppers. Fumigation is normally used to eradicate pests in plant quarantine, but phytotoxicity may can be appeared that affect the quality of the product. Low-temperature treatment, one of the most popular physical treatment, can reduce crop damage to preserve product quality, but it takes long time to kill pests, which can cause quality degradation. In this study, phytotoxicity of fumigants, phosphine(PH3), ethyl formate(EF) and PH3+EF on sweet peppers was investigated to use as basic data for physicochemical treatment. When treated with more than 35 mg/L of EF, phytotoxicity was occurred, and was not occurred with PH3. When low-temperature of 1.7 degrees treated for 15 days after fumigation, it seems to be no direct damage from low-temperature treatment. But quality of top of sweet pepper was decreased from 7 days after fumigation.

Honeybees are pollinating agent of economic importance, and a model organism for microbiome analysis. The microbiota plays a great role in honeybee health and development as such needs to be fully elucidated among Apis mellifera in Korea. using 16S rRNA gene illumina sequencing, the gut microbiota of Apis mellifera at four developmental stages under natural condition shows dysbiosis of essential microbiota, especially between the 5-days larvae and workers.

최근 벚나무에 벚나무깍지벌레에 의한 피해가 증가하여 친환경적인 방제제로서 곤충병원성 곰팡이인 Beauveria bassiana ARP14를 검증하였다. 경북 안동시 안동대학교 캠퍼스 내 벚나무에서 벚나무깍지벌레의 감염율을 조사하고, 벚나무의 연령을 추정하여 상관관계를 분석하였다. 곤충병원성 곰팡이의 살충력을 확인하 기 위해 약충의 이동성이 가장 활발한 4월 말부터 5월 중순까지 벚나무깍지벌레에 감염된 가지를 채집하여 23°C 의 항온기에 보관하면서 두 가지 곤충병원성 곰팡이(ARP14, AAD16)를 살포하여 살충제(스피로테트라맛 액상 수화제) 처리구와 살충률을 비교하였다. 그 결과 대조구(물처리)보다 곤충병원성 곰팡이를 살포한 가지에서 약충의 개체 수가 더 감소하였으나, 살충제를 처리한 가지에서 보다는 약충의 수가 많았다. 따라서 가로수로 많이 식재된 벚나무 해충 방제시 일어날 수 있는 사람에 대한 피해를 최소화할 수 있는 친환경 방제제로서 곤충병 원성 곰팡이를 사용할 수 있을 것이다.

The utilization of methyl bromide (MB) for quarantine purposes has been hampered by its designation as an ozone-depleting substance under the Montreal Protocol. The International Plant Protection Convention's (IPPC) call for alternatives to MB and a reduction in its usage. There is an urgent need to explore and implement substitutes. Despite some substitute agents like EDN being developed for wood, EDN has been limited due to various factors such as occupational risks. This study focuses on evaluating the efficacy of Sulfuryl Fluoride (SF) as a viable alternative fumigant against Reticulitermes speratus, one of major wood destroying pests. Experimental trials conducted at ambient temperature (23°C) revealed promising results, with SF demonstrating LCT50 and LCT99 values of 30.87 mg·h/L and 42.53 mg·h/L, respectively. Under low-temperature conditions (5°C), SF remained effective but with slightly higher LCT50 and LCT99 values of 151.62 mg·h/L and 401.90 mg·h/L, respectively. The penetration test, conducted using R. speratus-infested pine wood cubes, further highlighted SF's efficacy, with LCT50 and LCT99 values of 31.59 mg·h/L and 53.34mg·h/L at 23°C, indicating powerful penetration capabilities. When tested at a loading ratio of 90% (v/v) at 5.0mg/L for 24 hours in a 500L chamber as a middle-scale trial, SF achieved a 100% mortality, showing its potential as a suitable replacement for MB. These findings suggest that SF could open new markets as an MB substitute and enhance safety at quarantine sites when applied to imported and exported timber.

The striped fruit fly (SFF), Zeugodacus scutellata, is an agricultural pest species with a strong and rapid reproductive ability that can cause significant harm. To control the population of these kind of pests, the sterile insect technique (SIT) is being used as one of the effective methods. SIT involves the introduction of sexually transmitted factors that reduce the reproductive capacity of males. This study shows that knocking down the testis-specific serine/threonine protein kinase 1 (Zs-Tssk1) gene alters male fertility and male-initiated types of communication. Since Zs-Tssk1 influences the physiology of the testes, spermatogenesis is also affected, which in turn alters the lifespan of Zs-Tssk1 knock down group in comparison with the control. Based on these results, Zs-Tssk1 may be crucial in reproductive function, and its down-regulation may be helpful in controlling SFF through SIT.