Buffer materials play an important role in preventing the leakage of radionuclides from the residue. The mineralogical properties of these buffer materials are critical in repository design. This study presents the fundamental properties of Na-type MX80 and a novel Ca-type Bentonil- WRK. The CaO to MgO ratio in Bentonil-WRK was approximately 1:1, and the CaO to Na2O ratio was approximately 2.8:1. These results suggest that Bentonil-WRK demonstrates a lower swelling index compared to Gyeongju bentonite due to its CaO-to-MgO ratio’s proximity to 1:1, despite having a higher montmorillonite content than Gyeongju bentonite. The results of this research can provide useful foundational data for the evaluation of the thermal-hydraulic-mechanical-chemical behavior of buffer materials.

Buffer materials are one of the engineering barrier components in high-level radioactive waste disposal facilities. Compacted bentonite has been known as the most suitable buffer material so far, and research is being conducted worldwide to determine the characteristics of suitable bentonite blocks in each country. Therefore, this study aims to compare and analyze various properties of different buffer material candidates, including thermal, hydraulic, and mechanical properties. Buffer material candidates for Korea disposal system, Kyungju Bentonite (KJ-I, KJ-II), and Bentonil- WRK were compared. The properties were compared and analyzed based on experimental and literature data. The data obtained from this report can be used to understand the behavior of buffer materials and assess whether they meet various criteria, such as temperature and saturation, and ultimately serve as an essential input variable database for safety evaluations of disposal systems.

The presence of technological voids in deep geological repositories for high-level radioactive nuclear waste can have negative effects on the hydro-mechanical properties of the engineered barrier system when groundwater infiltrates from the surrounding rock. This study conducted hydration tests along with image acquisition and X-ray CT analysis on compacted Korean bentonite samples, which simulated technological voids filling to investigate the behavior of fracturing (piping erosion) and cracking deterioration. We utilized a dual syringe pump to inject water into a cell consisting of a bentonite block and technological voids at a consistent flow rate. The results showed that water inflow to fill technological voids led to partial hydration and self-sealing, followed by the formation of an erosional piping channel along the wetting front. After the piping channel generated, the cyclic filling-piping stage is characterized by the repetitive accumulation and drop of water pressure, accompanied by the opening and closing of piping channels. The stoppage of water inflow leads to the formation of macro- and micro cracks in bentonite due to moisture migration caused by high suction pressure. These cracks create preferential flow paths that promote longterm groundwater infiltration. The experimental test and analysis are currently ongoing. Further experiments will be conducted to investigate the effects of different dry density in bentonite, flow rate, and chemical composition of injected water.

In this study, a third metal layer with a higher corrosion potential than copper was introduced between the copper and cast iron layer to strengthen the corrosion resistance of the copper layer which is considered as a corrosion resistant barrier in the disposal container for spent nuclear fuel. Three types of corrosion-resistant metals, silver, nickel, and titanium, were selected as the intermediate insertion layer, and the galvanic specimens of two bonded metals were exposed to KURT (KAERI Underground Research Tunnel) groundwater and a high voltage of 1.0 V was applied to corrode the specimens at electrochemically accelerated condition. Corrosion of copper part was confirmed in Cu-Ti, Cu-Ni, and Cu-Ag galvanic specimens, but copper part was not corroded in Cu-Fe galvanic specimen. If the corrosion-resistant intermediate layer proposed in this study works properly, the local corrosion problem of copper disposal canister is expected to be some degree solved, which can apply to a welding part or a stress concentrated part.

In Korea, most temporary storage facilities for spent nuclear fuel are nearing saturation. As an alternative to this, the 2nd basic plan for high-level radioactive waste management specified the operation plan of dry interim storage facility. Meanwhile, the NSSC No. 2021-19 stipulates that it is necessary to evaluate the possibility and potential effect of accident before operating interim storage facility. Therefore, this study analyzed the categories of accident scenarios that may occur in dry storage facility as part of prior research on this. We investigated the case of categorization of dry storage facility accident scenarios of IAEA, NRC, KAREI, and KINS. The IAEA presented accident scenarios that could occur in on-site dry storage facility operated with silo and cask method. NRC has classified accident scenarios in dry storage facility and estimated the probability of accidents for each. KAERI and KINS selected major accident scenarios and analyzed the processes for each, in preparation for the introduction of dry storage facility in Korea in the future. Overall, a total of 10 accident scenarios were considered, and the scenarios considered by each institution were different. Among 10 scenarios, cask drop and aircraft collision were included in the categorization of most institutions. The results of this study can be used as basic data for cataloging accidents subject to safety evaluation when introducing dry interim storage facility in Korea in the future.

Any type of nuclear arms control or disarmament agreement requires some form of verification measure. Existing nuclear arms control treaties drew upon previous agreements such as the INF treaty, START, and IAEA nuclear safeguards inspections. However, previous treaties focused on limiting specific types of nuclear weapons and their delivery vehicles or reducing the total number of nuclear weapons rather than eliminating the nuclear enterprise as a whole. A potential nuclear disarmament verification treaty or agreement will depend on the geopolitical environment of the time as well as the national policies and priorities of each signatory state. Although research on the gradual reduction and eventual elimination of nuclear weapons is still ongoing, several states have cooperated to conduct experiments, exercises, and simulations on the procedures and technologies required for nuclear disarmament verification. Three of these efforts are the LETTERPRESS simulation conducted by the Quadrilateral Nuclear Verification Partnership (QUAD), NuDiVe Exercise conducted by the International Partnership for Nuclear Disarmament Verification (IPNDV), and the Menzingen experiment organized by the UNIDIR in partnership with the Swiss Armed Forces, Spiez Laboratory, Princeton University’s Program on Science and Global Security, and the Open Nuclear Network. These contain aspects for the development of a potential nuclear disarmament verification. The LETTERPRESS exercise conducted in 2017 tested potential activities and equipment inspectors might utilize in a nuclear weapon facility. The IPNDV NuDiVe exercises conducted in 2021 and 2022 tested the activities and equipment required for the verified dismantlement of a warhead within a dismantlement facility. Finally, the Menzingen experiment conducted in 2023 tested the practical procedures for the verification of a nuclear weapon’s absence at a storage site. This paper will analyze the three cases to offer considerations on the procedures and technologies future nuclear disarmament verification might include.

Arms control treaties during the Cold War generally used national technical means (NTM) to verify treaty compliance. This was because signatory states refused to agree on on-site inspection (OSI) measures since it would require some level of intrusion. Efforts on nuclear arms control such as the Limited Test Ban Treaty (LTBT) or Strategic Arms Limitation Talks (SALT) initially included some form of OSI but could not continue due to refusal from signatory states. The Intermediate-Range Nuclear Force (INF) treaty concluded between the US and the Soviet Union in 1978 was significant since both states agreed on a highly intrusive verification measure. The Strategic Arms Reduction Treaty (START) and the new START also called for OSI measures similar to the INF. Alongside reducing a significant number of nuclear warheads and limiting specific types of nuclear warhead delivery vehicles, these treaties also provided basic models for conducting on-site inspection (OSI). OSI measures primarily rely on the political agreement between signatory states. However, the structure, types of inspections, number of inspections allowed, and technology/equipment used in each of the regimes also differ according to the objectives of each treaty. The INF treaty and START are salient cases as basic models for current nuclear disarmament verification research. Thus, this paper will conduct a case study on the procedures and mechanisms required for nuclear arms control verification in terms of OSI. Using the implications drawn from the INF treaty and START, this paper offers considerations for a potential nuclear disarmament verification.

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.

Cholesterol is prone to oxidation, which results in the formation of cholesterol oxidation products (COPs). This occurs because it is a monounsaturated lipid with a double bond on C-5 position. Cholesterol in foods is mostly non-enzymatically oxidized by reactive oxygen species (ROS)-mediated auto-oxidative reaction. The COPs are found in many common foods of animal-origin and are formed during their manufacture process. The formation of COPs is mainly related to the temperature and the heating time the food is processed, storage condition, light exposure and level of activator present such as free radical. The level of COPs in processed foods could reach up to 1-10 % of the total cholesterol depending on the foods. The most predominant COPs in foods including meat, eggs, dairy products as well as other foods of animal origin were 7-ketocholesterol, 7 α-hydroxycholesterol (7α-OH), 7β-hydroxycholesterol (7β-OH), 5,6α-epoxycholesterol (5,6α -EP), 5,6β-epoxycholesterol (5,6β-EP), 25-hydoxycholesterol (25-OH), 20-hydroxycholesterol (20-OH) and cholestanetriol (triol). They are mainly formed non-enzymatically by cholesterol autoxidation. The COPs are known to be potentially more hazardous to human health than pure cholesterol. The procedure to block cholesterol oxidation in foods should be similar to that of lipid oxidation inhibition since both cholesterol and lipid oxidation go through the same free radical mechanism. The formation of COPs in foods can be stopped by decreasing heating time and temperature, controlling storage condition as well as adding antioxidants into food products. This review aims to present, discuss and respond to articles and studies published on the topics of the formation and inhibition of COPs in foods and key factors that might affect cholesterol oxidation. This review may be used as a basic guide to control the formation of COPs in the food industry.

Exploring earth-abundant, highly effective and stable electrocatalysts for electrochemical water splitting is urgent and essential to the development of hydrogen (H2) energy technology. Iron-cobalt layered double hydroxide (FeCo-LDH) has been widely used as an electrocatalystfor OER due to its facile synthesis, tunable components, and low cost. However, LDH synthesized by the traditional hydrothermal method tends to easily agglomerate, resulting in an unstable structure that can change or dissolve in an alkaline solution. Therefore, studying the real active phase is highly significant in the design of electrochemical electrode materials. Here, metal-organic frameworks (MOFs) are used as template precursors to derive FeCo-LDH from different iron sources. Iron salts with different anions have a significant impact on the morphology and charge transfer properties of the resulting materials. FeCo-LDH synthesized from iron sulfate solution (FeCo-LDH-SO4) exhibits a hybrid structure of nanosheets and nanowires, quite different from other electrocatalysts that were synthesized from iron chloride and iron nitrate solutions. The final FeCo-LDH-SO4 had an overpotential of 247 mV with a low Tafel-slope of 60.6 mV dec-1 at a current density of 10 mA cm-2 and delivered a long-term stability of 40 h for the OER. This work provides an innovative and feasible strategy to construct efficient electrocatalysts.

One of the taxa of the superfamily Gelechioidea, Stathmopodidae, is widely distributed around the world, with 39 genera and 390 species reported as of 2015. This family shares the common characteristic of carrying their long hind tibia, but depending on the species, they have a variety of wing patterns and colors. Additionally, while there are species classified as pests for causing damage to grains and fruits, there are also species that feed on moss, spore of ferns and aphids. Consequently, they exhibit a diverse range of morphological and ecological characteristics. However, due to the lack of research and similarities between species, there is still much confusion in identification and phylogenetic analysis to date. In this current situation, further research intends to resolve the confusion in the phylogenetic sutdy of Stathmopodidae not only through morphological and molecular analysis but also by incorporation the latest technologies.

The subfamily Acronictinae is established by Harris in 1841 based on the type species, Acronicta leporina.. In the Korean penisula, the acronictine moth Acronicta cuspis was initially reported by leech in 1889, and a total 45 species have been recorded to date. This brief overview cover adult and larval morphology, as well as ecological data, for more profound comprehension of the Acronictinae. Additionally, further research direction could involve conducting a phylogenetic analysis and clarifying the evolutionary relationships within the subfamily.

The family of Pterophoridae, also called ‘Plume moth’, is distributed all around the world. More than 1,100 species have been studied and reported in the most recent world catalogue, and it has been discovered 34 species from Korea. The reason why they are called Plume moth is that they have a distinct shape of wings, which makes them easily distinguished. This group have a 6－40mm wingspan, mostly have two-pronged forewings and three-pronged hindwings. Interestingly, their resting posture is T-shaped with the narrow forewings held perpendicular to the body, while the hindwings tucked under or folded within the forewings. They have slender bodies with long, fragile legs, and also have three types of color : plain white, mottled gray or brown. Pterophoridae has unique morphological characteristics, and it is an interesting group for us to look over them in general.