Wolsong Unit 1, a domestic heavy water reactor nuclear power plant, was permanently shut down in December 2019. Accordingly, Wolsong Unit 1 plans to prepare a Final Decommissioning Plan (FDP), submit it to the government by 2024, receive approval for decommissioning, and begin full-scale decommissioning. One of the important tasks in the decommissioning of Wolsong Unit 1 is to determine the decommissioning strategy. It is necessary to decide on a decommissioning strategy considering various factors and variables, secure the technical background, and justify it. The selection of a decommissioning strategy is best achieved through the use of formal decisionmaking assistance techniques, such as considerations related to influencing factors. It is very important to understand the basic decommissioning strategy alternatives and whether sufficient consideration has been given to situations where only a single unit is permanently shut down in a multi-unit site like Wolsong Unit 1, while the remaining units are in normal operation. As a process for selecting a decommissioning strategy, first, all considerations that could potentially affect decommissioning presented in the KINS Decommissioning Safety Review Guidelines were synthesized, influencing factors to be used in the decision-making process were determined, and the concept was defined. In order to select the most appropriate decommissioning strategy by considering various evaluation attributes of possible decommissioning alternatives (immediate dismantling and delayed dismantling), the Wolsong Unit 1 decommissioning strategy was evaluated by reflecting the AHP decision-making technique.

The effectiveness of a crystalline natural barrier in providing sealing capabilities is based on the behavior of numerous fractures and their intersections within the rock mass. It is important to evaluate the evolving characteristics of fractured rock, as the hydro-mechanical coupled processes occurring through these fractures play a dominant role. KAERI is actively developing a true tri-axial compression test system and concurrently conducting hydro-mechanical experiments using replicated fractured rock samples. This research is focused on a comprehensive examination of coupled processes within fractures, with a particular emphasis on the development of true tri-axial testing equipment. The designed test system has the capability to account for three-dimensional stress conditions, including vertical and both maximum and minimum horizontal principal stresses, realizing the disposal conditions at specific underground depths. Notably, the KAERI-designed test system employs the mixed true tri-axial concept, also known as the Mogi-type, which allows for fluid flow into fractures under tri-axial compression conditions. This system utilizes a hydraulic chamber to maintain constant stress in one direction through the application of oil pressure, while the other two directional stresses are applied using rigid platens with varying magnitudes. Once these mechanical stress conditions are established, control over fluid flow is achieved through the rigid platens in contact with the specimen section. This pioneering approach effectively replicates in-situ mechanical conditions while concurrently observing the internal fluid flow patterns within fractures, thereby enhancing our capacity to study these coupled phenomena. As future research, numerical modeling efforts will be proceeding with experimental data-driven approaches to simulate the coupled behavior within the fractures. In these numerical studies, two distinct fracture geometry domains will be generated, one employing simplified rough-walled fractures and the other utilizing mismatched rough-walled fractures. These investigations mark the preliminary steps in the process of selecting and validating an appropriate numerical model for understanding the hydro-mechanical evolution within fractures.

The radionuclide management process is a conditioning technology to reduce the burden of spent fuel management, and refers to a process that can separate and recover radionuclides having similar properties from spent fuels. In particular, through the radionuclide management process, high heat- emitting, high mobility, and high toxicity radionuclides, which have a significant impact on the performance of disposal system, are separated and managed. The performance of disposal system is closely related to properties (decay heat and radioactivity) of radioactive wastes from the radionuclide management process, and the properties are directly linked to the radionuclide separation ratio that determines the composition of radionuclides in waste flow. The Korea Atomic Energy Research Institute have derived process flow diagrams for six candidates for the radionuclide management process, weighing on feasibility among various process options that can be considered. In addition, the GoldSim model has been established to calculate the mass and properties of waste from each unit process of the radionuclides management process and to observe their time variations. In this study, the candidates for the radionuclide management process are evaluated based on the waste mass and properties by using the GoldSim model, and sensitivity analysis changing the separation ratio are performed. And the effect of changes in the separation ratio for highly sensitive radionuclides on waste management strategy is analyzed. In particular, the separation ratio for high heat-emitting radionuclides determines the period of long-term decay storage.

To mark the 70th anniversary of the alliance between South Korea and the United States, President Yoon Seok-youl of South Korea and President Joseph R. Biden of the United States convened at the White House, adopting the pivotal “Washington Declaration.” This significant act paved the way for the establishment and institutionalization of the ROK-US Nuclear Consultative Group (NCG). The NCG is envisioned as a mechanism to address North Korea’s nuclear threat, striving for nuclear sharing and a nuclear defense system, thereby alleviating concerns about nuclear security. The NCG is perceived as a crucial advancement in the realm of ‘tailored extended deterrence’ on the Korean Peninsula. However, its operational scope and efficacy remain subjects of debate within South Korea. A comparative analysis with other consultative entities, such as NATO’s Nuclear Planning Group (NPG) and Extended Deterrence Strategy Consultative Group (EDSCG), raises questions about NCG’s unique contributions and potential functional overlaps. Furthermore, the establishment of the NCG represents a notable progression in the strengthened ROK-US alliance. This progression coincides with the resumption of large-scale joint nuclear security military exercises under the new administrations of both nations. Anticipated future operations within the NCG framework encompass the continual deployment of strategic assets and the execution of nuclear simulation exercises. Such actions serve not merely as a deterrent message to North Korea but also aim to instill confidence in the US’s commitment to extended deterrence among the South Korean populace. This study aims to highlight the significance and implications of the ROK-US Nuclear Consultative Group (NCG) through an exhaustive comparative analysis of existing nuclear security consultative bodies and pertinent nuclear security policies. Moreover, this research emphasizes strategies to boost the NCG’s effectiveness, the necessity for policy enhancements to foster South Korea’s nuclear security autonomy, and the importance of raising nuclear security awareness among the general public.

본 연구는 미국의 동아시아 안보전략과 해외주둔군 전략, 확장억제전 략의 변화를 분석하고, 북한의 핵무기 고도화에 대비한 주한미군과 핵우 산 정책을 고찰한다. 한미동맹이 체결된 1953년 이후, 미국은 한반도 안 보의 중심 역할을 수행했으나 비대칭 동맹으로 인한 동맹 딜레마와 미군 의 역할 및 규모 변화가 발생했다. 핵우산 정책은 냉전기 소련의 핵전술 에 대항하여 확장되어 현재까지 적용되고 있으며, 2023년에는 워싱턴 선 언을 통해 한미 핵협의그룹(NCG)이 창설되었다. 이를 통해 상시적인 확 장억제가 논의되고 있으며, 굳건한 한미 동맹체제와 안보공약이 SCM을 통해 재확인되었다. 이제는 냉전 시기의 미군 주둔과 자동개입 문제는 중국의 G2국가 발전, 북한의 핵과 미사일 도발 등으로 시대적 변수가 달 라져 있다. 따라서 미국의 주한미군 정책, 개입 문제, 확장억제전략에 대 한 신중한 검토와 대비가 필요하다. 본 연구는 미국의 동아시아 전략, 주 한미군, 확장억제전략에 대해 고찰하고 한반도 안보에 대한 전망을 목적 으로 한다.

Sweet persimmons are valuable commodity in the export market. However, present of insect pest such as Asiacornococcus kaki can cause limit to many export markets. In this study, ethyl formate(EF), as alternative to methyl bromide(MB), was used in scale-up commercial trial(20ft reefer). Application of 50 g/m3 of EF for 6 hours at 5 ℃ showed proven efficacy against all developmental stages of A. kaki without LLDPE-packaging fruits and no phytotoxic damage on sweet persimmons. This study demonstrated that EF fumigation can be effectively control to target A. kaki before packaging with LLDPE-film of fruits.

As global warming and consumer’s preference for tropical/subtropical fruits increase, the number of orchards cultivating tropical/subtropical fruits in Korea is increasing. Accordingly, concerns about the introduction of exotic invasive pests that host tropical fruits. In this study, efficacy of ethyl formate(EF), as alternative to methyl bromide(MB), was evaluated. Commercial trial of EF was conducted in mango post-harvest storage conditions for controlling Scirtothrips dorsalis. Application of 10 g/m3 of EF for 4 hours at 10 ℃ showed proven efficacy on S. dorsalis without any phytotoxic damage on mango fruits in that condition.

Nutrient acquisition by insect herbivores affect all aspect of the the lifespan of individauls. For seed-sucking insect herbivores, they face challenges with nutrient acquisition due to requirement for extra-oral digestion of seed contents into a readily-ingestible state. In this study, we demonstrated environmentally-transmitted Caballeronia insecticola allow seed-sucking R. pedestris to overcome challenges with extra-oral digestion. Through the evaluation, first, we found symbiotic insects exhibited enhanced feeding efficiency by consuming significantly larger amount of food per feeding attempt compared to apo-symbiotic insects (P<0.05). Then, we observed feeding behavior modification in the symbiotic insects from the behavior tracking evaluation. Symbiotic insects displayed dichotomic behavior which can be generally divided into early focused feeding and later subdued resting periods. By contrast, apo-symbiotic insects displayed unordered behavior by frequent switches between feeding and walking behavior.

최근 기후변화로 인해 외래 무척추동물(곤충)의 돌발발생 가능성이 높아지고 있는 추세를 감안할 때 이들에 대한 확산 및 변화예측 진단을 통한 조기방제의 중요성이 대두되고 있다. 그러나, 외래곤충의 종 정보 및 정확한 침입경로가 충분치 않아 문제해충이 될 가능성이 매우 높은 것이 사실이다. 또한, 신속정확한 정책결정을 위해서 는 현장조사자료가 체계적으로 수집되어 종합되어야만 정확한 진단 및 방제에 활용될 것이므로 이에 대한 다양 한 장치가 필요하다. 현재 국내 서식 중인 주요 산림해충 일부를 제외한 종들은 대부분 외래곤충으로 돌발적으로 대발생한 해충이 많이 포함되어 있어 국내에 유입된 외래 곤충에 대한 체계적인 데이터 확보를 통해 정착, 확산, 생태계 영향 예측모델 개발 및 활용시스템의 구축이 요구되는 실정이다. 따라서, 본 연구는 외래 곤충의 전국적인 모니터링을 통해 분포정보 및 생태정보 등의 중요 데이터 수집과 최신 정보를 활용하여 국내 유입된 외래 곤충의 정착, 확산, 생태계 영향 및 변화예측을 위한 전략수립과 모바일 등을 이용한 전자야장의 사용에 대해 논하고자 한다.

Plant biosecurity refers to measures that aim to prevent the introduction and spread of pests that pose potential risks to plant health. This core concept underpins the approach undertaken by the National Plant Protection Organization (NPPO), where pre-border, border, and post-border biosecurity activities focus on early detection and rapid response. The approach recognizes the continuum from pre- to post-border, resource allocation is currently being reviewed to ensure an appropriate balance for effective risk mitigation. National Priority Plant Pests with contingency plans highlight the types of threats facing the Korean peninsula faces from exotic plant pests. This will lead to transparency of NPPO activities and ensure that it has the people, resources, tools and systems to address its most important priorities and effectively manage current and future biosecurity challenges.

In this study, in order to establish a strategy for developing an fire following earthquake risk assessment method that can utilize domestic public databases(building datas, etc.), the method of calculating the ignition and fire-spread among the fire following earthquake risk assessment methodologies proposed by past researchers is investigated After investigating and analyzing the methodology used in the HAZUS-MH earthquake model in the United States and the fire following earthquake risk assessment methodology in Japan, based on this, a database such as a domestic building data utilized to an fire following earthquake risk assessment method suitable for domestic circumstances (planned) was suggested.

이 연구는 21세기에 들어 핵전력 강화에 전념하는 북한의 핵전략을 내 부적 법과 제도의 정비 사례를 통해 분석한다. 북한은 2012년 헌법 서문 을 개정하여 ‘핵보유국’임을 천명하였고, 2013년 “자위적 핵보유국의 지 위를 더욱 공고히 할 데 대하여(소위 핵보유국법)”와 2022년 “조선민주 주의인민공화국 핵무력정책에 대하여(소위 핵무력정책법)을 통해 핵전략 을 세부적으로 발전시키고 있다. 2013년 대비 2022년의 법률은 상당부 분 공세적, 권한위임형 핵전략을 보인다는 특징이 있다. 본 논문은 두 법 률의 내용 변화를 리케의 전략 3요소(목표, 방법, 수단)를 바탕으로 분석 하고, 비슷한 핵전략의 변화를 보였던 파키스탄의 사례와 비교하여 함의 를 도출한다. 결론적으로는 바틀렛의 모델을 바탕으로 북한 핵전략의 전 략적 균형 달성 여부를 고찰해본다.