Wet solid wastes including spent ion exchange resins, evaporator concentrates and sludges require solidification to transform wastes into an acceptable solid, monolithic form for final disposal. The development of the process control program for the solidification of radioactive sludges generated at nuclear power plants has been in progress to provide reasonable assurance that the solidified product will meet the established waste acceptance criteria for solidified waste. A mobile solidification system to produce the solidified waste in the size of a 200 L drum was used, which adopts the in-line mixing method where the waste and binder are mixed and then transferred to the disposable container. To simulate radioactive sludges, non-radioactive sludges are synthesized and the specimens are prepared by using them. The qualification tests on the prepared specimens including the compressive strength test, the thermal cycling test, the irradiation test, the leach test, the immersion test, etc. have been performed to qualify recipes for a range of waste compositions. The results of the tests will be analyzed and discussed.

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.

Insects, including aphids, caterpillars, and beetles, have a significant impact on biodiversity, ecology, and the economy by consuming various plant tissues like leaves, stems, and fruits, leading to issues such as holes, defoliation, and impaired growth. Consequently, our study's primary goal was to establish a model system capable of identifying and tracking insects, covering aspects like their behaviors, movements, sizes, and patterns. Our research has successfully produced a 3D monitoring system specifically designed for continuous insect tracking by applying it to brown planthopper. This technology allows for in-depth exploration of insect behaviors and their interactions with plants and crops. The potential applications of this technique are highly promising, offering valuable assistance to researchers in unraveling insect behavior and ecological dynamics and driving further advancements in these crucial research areas.

Scotinophara lurida is one of major sap-sucking pests in an organic rice farming paddy fields in Korea. Several Poaceae grasses (e.g, rice, barley etc) have been known as a host plant. To find out a true host plant of S. lurida, the developmental characteristics such as weight gain and developmental duration were checked on total eight grasses species including rice and corn. In the results, weight of the fifth nymphal stage was the highest value in the barnyard millet and rice plant. In addition, nymphal duration was the shortest value in the barnyard millet and rice plant. But, in corn and common millet plant, S. lurida nymphs could not complete the development to the adult stage. These results suggest that six Poaceae grasses including rice and barnyard millet out of eight test grasses are close related to true host plants of S. lurida.

Because Scotinophara lurida has the habit of living under the rice plant, an introduction of a method for efficient control when spraying eco-friendly organic materials is needed. In this study, we investigated the density of S. lurida in drained- and irrigated-paddy field after spraying an organic material containing garlic bulb extracts, which has high insecticidal activity in S. lurida in direct spraying test in glass tube. As a result, an irrigated rice paddy showed a control effect of 66.4% after 3 days of spraying and 86.2% after 7 days, while a drained rice paddy showed a control effect of 33.9% after spraying and 61.9% after 7 days. These results suggest that effective control can be achieved in irrigated rice fields if organic farming materials are evenly sprayed and reach to the body of S. lurida. It is remained to study how irrigated water do contribute to increase the insecticidal effect in the future.

Mesophase pitch is a unique graphitizable material that has been used as an important precursor for highly graphitic carbon materials. In the current study, we propose to consider a spinnable mesophase pitch as a lyotropic liquid crystalline solution composed of solvent components and liquid crystalline components, so-called mesogen or mesogenic components. Among mesophase pitches, the supermesophase pitch is defined as a mesohpase pitch with 100% anisotropy, and can only be observed in pitches with a proportion of mesogenic components exceeding the threshold concentration (TC). We also examined the critical limit of AR synthetic pitch and 5 experimental spinnable mesophase pitches (SMPs). Then, we examined the effect of the solvent component on the minimum required amount of mesogenic component using a selected solvent component instead of their own solvent components. AR pitch showed 100% anisotropy with the least amount of its mesogenic component, THF insoluble components, of 60 wt.%. The solvent component, THF soluble components, extracted from AR-pitch, which has a molecular weight pattern similar to that of the original material but more amount of naphthenic alkyl chains, showed better solvent functionality than those of other THF solubles (THFSs) from other as-prepared spinnable mesophase pitches. This is why a lower amount of AR THFS can produce a supermesophase pitch when combined with the THFI (mesogenic components) of other experimental mesophase pitches. As a result of the current analysis, we define the mesogens as molecules that not only readily stack, but also maintain stacking structures in a fused state in the solution. The solvent component, on the other hand, is defined as molecules with a structure that readily decomposes in a fused state in the solution.

The separation of hydrogen isotopes is a critical issue in various fields, such as deuterium or tritium production and the treatment of radioactively contaminated water. In this presentation, we describe the pervaporative separation of hydrogen isotopes using proton conductive membranes and underlying separation mechanism. We investigated the H/D separation factors of perfluorosulfonic acid (Nafion) and polybenzimidazole membranes using pervaporation, and found that both membranes exhibited similar separation factors of approximately 1.026. Water permeation flux through the membranes was highly dependent on their thickness and type, and increased with operation temperature. However, the effect of temperature on H/D separation factor was negligible. We also demonstrated the cascade separation of H/D, indicating the potential application of multi-stage operation. We found that surface transport mechanisms such as hydron hopping contributed the most to H/D separation during the pervaporation process of proton conductive membranes.

Domestic NPPs had produced the paraffin-solidifying concentrate waste (PSCW) for nearly 20 years. At that time radioactive waste management policy of KHNP was to reduce the volume and to store safely in site. The PSCW has been identified not to meet the leaching index after introducing the treatment system. PSCW has to be treated to meet current waste acceptance criteria (WAC) for permanent disposal. PSCW consists of dried concentrate 75% and paraffin 25% of volume. When PSCW is separated into a dried concentrate and a paraffin by solubility, total volume separated is increased twice. Final disposal volume of dried concentrate can reach to several times when solidifying by cement even considering exemption. Application of polymer solidification technology is difficult because dried concentrate is hard to make form to pellet. When PSCW is packaged in High Integrity Container (HIC), volume of PSCW is equal to the volume before package. The packaging process of HIC is simple and is no necessary of large equipment. It is important to recognize that HIC was developed to replace solidification of waste. HIC has as design goal a minimum lifetime of 300 years under disposal environment. The HIC is designed to maintain its structural integrity over this period, to consider the corrosive and chemical effects of both the waste contents and the disposal environment, to have sufficient mechanical strength to withstand loads on the container and to be capable of meeting the requirements for a Type A transport Package. The Final waste form is required for facilitating handling and providing protection of personnel in relation to solidification, explosive decomposition, toxic gases, hazardous material, etc. Structural stability of final waste form is required also. Structural stability of the waste can be provided by the waste itself, solidifying or placing in HIC. Final waste form ensure that the waste does not structurally degrade and affect overall stability of the disposal site. The HIC package contained PSCW was reviewed from several points of view such as physicochemical, radiological and structural safety according to domestic WAC. The result of reviewing shows that it has not found any violation of WCP established for silo type disposal facility in Gyeongju city.

A conventional porous carbon is still a very promising material for the removal of gaseous pollutants because of its abundant surface functional groups and a high specific surface area. Here, we prepared an environment-friendly uniform N-rich narrow micropore activated carbon, for the removal of formaldehyde, based on steam activation and N-rich with chitin as the starting material. A sample carbonized at 500 °C and steam activated at 800 °C (CAC800) showed a reasonable yield (55%) with uniform and narrow micropores without mesopores but having a balanced nitrogen functionality. CAC800 possesses outstanding formaldehyde removal capabilities under both dry and wet (humidity 45%) conditions. In addition, when compared with commercial activated carbon materials, we clearly demonstrated that the existence of high nitrogen content with uniform and narrow micropores simultaneously removed formaldehyde, effectively.

Currently, treatment and disposal suitability verification methods have not been established for radioactive waste, such as spent filters temporarily stored in each plant, so the WCP (Waste Certification Program) can be applied to verify the suitability of non-conforming waste at the site. In this study, WCP components such as certification organizations, certification methods, certification documents, and quality assurance (QA) plan that should be considered when developing WCP applicable to spent filter disposal were reviewed and presented. First, a certification organization consists of a certification organization that performs certification work, a certification support organization related to waste generation and treatment, and a quality control organization for waste certification. Especially, the support organization should support the implementation of WCP, so that spent filter processing procedures such as generation information management and immobilization can be properly packaged and transported. Second, in identifying the waste characteristics of the certification method, each characteristic identification procedure and certification method of the acceptance criteria should be described, evidence examining the suitability of general, radiological, physical, chemical, and biological requirements, and processes related to measurement and sampling should be established. In identifying characteristics, satisfaction of waste form, free water requirements, and whether it is subject to immobilization should be checked priorly, and a method of confirming particulate matter and securing filling rate when packaging compressed filters should be included. It is very important to develop a technology for verifying the safety and quality of the immobilized material because immobilization of the filters can be a processing method that satisfies various characteristic criteria. Meanwhile, it is essential to collect samples and develop scaling factors to identify the nuclides of filters and prove that they are below the concentration limits. For chemical and biological requirements, the characteristics are identified through generation information documents, corrective actions are taken and documented in case of nonconformance. Third, certification documents should include immobilization procedure manual, characteristic report, and characteristic test manuals such as free water, particulate matter and filling rate, radiation measurement method manual for packages, profile, and generation documents. Fourth, the QA plan should analyze the QA system of the plants, check the QA inspection details, establish general requirements for QA of spent filter disposal, and specify step-by-step certification work QA activities. In this study, considerations to ensure the disposal suitability at all stages from generation to disposal of spent filter were presented, and development of a WCP could contribute to preventing nonconformance.

As the decommissioning of Kori Unit 1 progresses, securing technology for treatment and disposal of radioactive wastes that have not been disposed of so far, such as spent filters, is recognized as an urgent task. In this study, a method of confirming the disposal suitability of spent filters was presented by reviewing the waste characteristics as presented in the waste acceptance criteria (WAC). The waste characteristics to be satisfied to ensure disposal suitability of waste are largely classified into general requirements, solidification and immobilization requirements, radiological requirements, physical requirements, chemical requirements, and biological requirements. First, the general requirement is to prove that the prohibited waste form has not been introduced into items related to waste form and packaging, and to confirm the suitability of disposal through step-by-step packaging photos, generation information, X-ray inspection, and visual inspection. Second, in the solidification and immobilization requirements, spent filters are non-homogeneous waste, and if the total radioactivity concentration of nuclides with a half-life of more than 20 years is 74,000 Bq·g−1 or more, they must be immobilized. Third, in order to meet the characteristic criteria for nuclides and radioactivity concentration, sampling and scaling factors development are required and based on this, nuclides must be identified and demonstrated to be below the disposal concentration limits. Surface dose rate and surface contamination should be measured in accordance with standardized procedures and disposal suitability should be confirmed through document tests recording the measured values. Fourth, in order to satisfy the physical requirements of the particulate matter and filling rate characteristics, the spent filter must be immobilized, if necessary, thereby ensuring disposal suitability. Meanwhile, free water in the spent filter should be removed through pre-drying and dehydration, and the disposal suitability should be confirmed by applying a test. Fifth, the criteria for chelating agents should be checked for disposal suitability through operation records and component analysis of spent filters, and documents, that can prove harmful substances are removed in advance and no harmful substances are included in the package, should be provided. Lastly, in biological requirements, if the spent filters contain corrosive or infectious substances, they should be removed in advance and disposal suitability should be confirmed by providing documents that can prove that such substances are not included in the package.

This study established a process to ensure the disposal suitability of spent filters stored in the untreated state in Kori unit 1 and presented the following procedures and requirements for confirming the disposal suitability for each process. The process for securing spent filter disposal suitability consists of collecting spent filters, compression, immobilization, analysis and packaging, and storage stages. The requirements for confirming the acceptance criteria for each process are as follows. (1) Collecting: Since the high radioactivity spent filters are being stored in the filter room of Kori unit 1, those are collected by a remote system to minimize the exposure dose of workers due to spent filter handling. In order to satisfy the surface dose rate requirements, spent filters with a surface dose rate of 10 mSv·hr−1 or more are classified and collected, and stored temporary storage place until a separate treatment plan is determined. The checkpoints in this process are the surface dose rate, etc. (2) Compression: The collected spent filters are analyzed gamma nuclides such as Co-60 and Cs-137, using a field-applicable nuclide analyzer, and then applying the scaling factors to determine whether it is disposable. Spent filters whose radioactivity concentration is confirmed to be less than the disposal concentration limit is compressed into compression ratios determined by surface dose rate. The checkpoints in this process are nuclide information, surface dose rate, compression ratio, spent filter loading quantity, etc. (3) Immobilization: A spent filter is a non-homogeneous waste that is immobilized with a proven safety material such as cement if the total radioactivity concentration of nuclides with a half-life of more than 20 years is 74,000 Bq·g−1. Meanwhile, immobilization of inhomogeneous waste can be considered to satisfy disposal criteria such as particulate matter and filling rate. The checkpoints in this process are the immobilizing material, filling rate, etc. (4) Analysis and Packaging: Immobilized drums shall be determined to be 95% or more of the total radioactivity of waste packages by measuring the radioactivity concentration of nuclides using a nuclide analysis device. Finally, measure the surface dose rate and surface contamination of the package, and attach the package label recording the identification number, date, total radioactivity, surface dose rate, and surface contamination information to the packaging container. (5) Storage: Packaging containers are moved to and stored in a temporary waste storage or storage area before disposal.

Colorectal cancer causes the most cancer-associated death worldwide, having a high cancer incidence. Pectin is a complex polysaccharide present in various fruits, emerging as an anti-carcinogenic candidate. Although pectin has a suppressive capacity for colon carcinogenesis, the effect of reactive oxygen species (ROS) generation and colonic aberrant foci formation in the colon carcinogenesis mouse model remains unclear. Therefore, this study investigates the regulatory effect of pectin supplementation on colon carcinogenesis induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in mice. In an animal experiment, thirty male institute for cancer research (ICR) mice were divided into two experimental groups; AOM/DSS (control group) and AOM/DSS + pectin (5% in drinking water). Furthermore, the number of aberrant crypt foci (ACF) and aberrant crypt (AC) on colonic mucosa were counted, and thiobarbituric acid-reactive substances (TBARS) assay was performed to estimate lipid peroxidation in feces. Pectin treatment significantly decreased the number of ACF and AC per colon compared with the control. Additionally, fecal TBARS level in the pectin group was significantly lower than those in the control group. Conclusively, these findings indicate that pectin-inhibited hyperplastic alteration and oxidative stress suppress colitis-associated colon carcinogenesis.

Colon cancer has been considered a leading cause of cancer-associated death. Folic acid is a vitamin necessary for cellular physiological functions and cell viability. However, the association between folic acid intake and colon cancer has been examined in several prospective cohort studies are controversial. This study investigated the effects of folate intake on colon carcinogenesis and oxidative stress in an azoxymethane (AOM)/dextran sodium sulfate (DSS) institute for cancer research (ICR) mouse model. Thirty male ICR mice (5 weeks old) were divided into the control group and the experimental group supplied 0.03% folic acid via drinking water (50 mL/week/mouse) for 6 weeks. To induce colonic pre-neoplastic lesions, the animals were subcutaneously injected three times weekly with AOM (10 mg/kg body weight), followed by 2% DSS in drinking water for a week. Folic acid supplementation significantly suppressed the total number of aberrant crypt foci and aberrant crypts. Histological image data showed that folic acid supplementation attenuated neoplastic change. In addition, we measured the thiobarbituric acid reactive substances concentration of dry feces samples to identify the effect of folic acid on reactive oxygen accumulation. The folic acid supplementation group had reduced reactive oxygen species levels in dry feces compared to the control group. In conclusion, these findings indicate that folic acid suppresses colon carcinogenesis and oxidative stress in an AOM/DSS mouse model.