In the event of a loss of a SNF (spent nuclear fuel) transport cask during maritime transportation, it is essential to evaluate the critical depth at which the integrity of the cask can be maintained under high water pressure. SNF transport casks are classified as Type B containers and the integrity of of the containment boundary must be maintained up to a depth of 200 meters unless the containment boundary was breached under beyond-design basis accidents. However, if an intact SNF cask is lost at a depth deeper than 200-meter, release of radioactive material may occur due to breach of containment boundary with over-pressure. In this study, we developed a code for the evaluation of the pressure limit of SNF transport cask, which can be evaluated by inputting the main dimensions and loading conditions of cask. The evaluation model was coded as a computer module for ease of use. In the previous study, models with three different fidelities were developed to ensure the reliability of the calculation and maintain sufficient flexibility to deal with various input conditions. Those three models consisted of a high-fidelity model that provided the most realistic response, a low-fidelity model with parameterized simplified geometry, and a mathematical model based on the shell theory. The maximum stress evaluation of the three models confirmed that the mathematical model provides the most conservative results than the other two models. The previous results demonstrate that mathematical models can be used in the code of computer modules. In this study, additional models of transport cask were created using parametric modeling techniques to improve the accuracy of the pressure limit assessment code for different cask and situations. The same boundary conditions and loading conditions were imposed as in the previous simplified model, and the maximum stress results considering the change in the shape of the transport container were derived and compared with the mathematical model. The comparison results showed that the mathematical model had more conservative values than the simplified model even under various input conditions. Accordingly, we applied the mathematical model to develop a transportation container pressure limit evaluation code that can be simulated in various situations such as shape change and various situations.

PURPOSES : This study proposes an index for analyzing mobility based on smartcard and taxi data to evaluate imbalances in public transit. METHODS : The proposed mobility index is calculated based on the difference between the mobility indexes of public transit and taxis using the variables of the in-vehicle time, waiting time, and driving ratio. For a more detailed analysis, the distances are divided into short distances, medium distances, and long distances. RESULTS : Public transit mobility indexes are generally evenly distributed, but the taxi mobility indexes are located in the largest legend. When comparing the respective mobilities of public transit and taxis, many areas with a high mobility of taxis (similar to the distribution) exist, especially in the outskirts such as Dobong-gu, Nowon-gu, Gangdong-gu, Guro-gu, Geumcheon-gu, and Eunpyeong-gu. On average, the mobility of public transit according to the distance is smaller in a short distance and higher in a long distance. CONCLUSIONS : The results demonstrate the use of the proposed index for analyzing the basic statuses of complementary indexes for evaluating public transit imbalances. In the future, more detailed results (including socioeconomic variables corresponding to the grid areas) should be studied to identify the impacts of the mobility index.

APro, a modularized process-based total system performance assessment framework, was developed at the Korea Atomic Energy Research Institute (KAERI) to simulate radionuclide transport considering coupled thermal-hydraulic-mechanicalchemical processes occurring in a geological disposal system. For reactive transport simulation considering geochemical reactions, COMSOL and PHREEQC are coupled with MATLAB in APro using an operator splitting scheme. Conventionally, coupling is performed within a MATLAB interface so that COMSOL stops the calculation to deliver the solution to PHREEQC and restarts to continue the simulation after receiving the solution from PHREEQC at every time step. This is inefficient when the solution is frequently interchanged because restarting the simulation in COMSOL requires an unnecessary setup process. To overcome this issue, a coupling scheme that calls PHREEQC inside COMSOL was developed. In this technique, PHREEQC is called through the “MATLAB function” feature, and PHREEQC results are updated using the COMSOL “Pointwise Constraint” feature. For the one-dimensional advection-reaction-dispersion problem, the proposed coupling technique was verified by comparison with the conventional coupling technique, and it improved the computation time for all test cases. Specifically, the more frequent the link between COMSOL and PHREEQC, the more pronounced was the performance improvement using the proposed technique.

Oral squamous cell carcinoma (OSCC), which accounts for approximately 90% of oral cancers, has a high rate of local recurrence and a poor prognosis despite improvements in treatment. Exosomes released from OSCC cells promote cell proliferation and metastasis. Although it is clear that the biogenesis of exosomes is mediated by the endosomal sorting complex required for transport (ESCRT) machinery, the gene expression pattern of ESCRT, depending on the cell type, remains elusive. The exosomal release from the human OSCC cell lines, HSC-3 and HSC-4, and their corresponding gefitinib-resistant sub-cell lines, HSC-3/GR and HSC-4/GR, was assessed by western blot and flow cytometry. The levels of ESCRT machinery proteins, including Hrs, Tsg101, and Alix, and whole-cell ubiquitination were evaluated by western blot. We observed that the basal level of exosomal release was higher in HSC-3/GR and HSC-4/GR cells than in HSC-3 and HSC-4 cells, respectively. Long-term gefitinib exposure of each cell line and its corresponding gefitinib-resistant sub-cell line differentially induced the expression of the ESCRT machinery. Furthermore, whole-cell ubiquitination and autophagic flux were shown to be increased in gefitinib-treated HSC-3 and HSC-4 cells. Our data indicate that the expression patterns of the ESCRT machinery genes are differentially regulated by the characteristics of cells, such as intracellular energy metabolism. Therefore, the expression patterns of the ESCRT machinery should be considered as a key factor to improve the treatment strategy for OSCC.

한국통합물류협회의 발표에 따르면, 2021년도 국내 총 택배 물량은 33억 7천만 개로 전년대비 7.59% 증가했고 매출액은 8조 5,800억 원으로 전년대비 14.6% 증가한 것으로 나타났으며 이러한 증가추세는 향후 지속될 것으로 전망된다. 이러한 택배 물량을 처리함에 있어 작업자는 대표적인 근골격계 부담작업에 노출되어 각종 근골격계 질환 유발 및 능률 저하가 갈수록 심화되고 있는 상황이다. 이에 따라 최신 통신네트워크 기술을 기반으로 하여 작업자와 자율주행 무인 운반차(Automated Guided Vehicle, AGV) 그리고 로봇의 협업을 지원하기 위한 기술개발에 대한 관심이 고조되고 있다. 본 연구에서는 LTE / 5G와 같은 최신 통신네트워크 환경 하에서 물류센터에서 자율주행하면서 택배의 상/하차 작업을 수행하는 Horizontal Scissor Lift를 갖는 AGV를 개발하고 택배 분류작업을 수행하는 로봇이 AGV와 협업을 가능하도록 하여 물류 집하 및 분배 작업이 통합된 물류 자동화 플랫폼을 구축한다. 본 물류 자동화 플랫폼은 자율 주행하면서 택배를 상/하차 하는 Scissor Lift-type AGV, 택배 분류를 위한 로봇, 다수의 AGV의 충돌을 방지하고 작업지시 및 작업상태 확인, 작업결과 피드백 등의 실시간 모니터링을 위한 관제 시스템 등으로 구성된다. 특히, 본 논문에서는 Horizontal Scissor Lift를 갖는 AGV의 구체적인 설계 및 해석결과를 제시하고, AGV 시제품에 대해 이동속도, 긴급 제동거리 및 위치정밀도에 대한 성능 평가를 수행함으로써 개발되는 AGV 시스템의 성능을 검증한다.

To transport radioactive waste generated during the decommissioning of Kori Unit 1, transport containers of various sizes are being developed. Since these radioactive decommissioning waste transport containers are larger than the specifications of the existing IP-2 type transport containers, which are for operational radioactive waste, design of the CHEONG-JEONG-NURI needs to be changed when transporting them to disposal facility using the CHEONG-JEONG-NURI, which carries operational radioactive waste. In this study, design changes of the CHEONG-JEONG-NURI, cargo hold modification plan for efficient loading of radioactive decommissioning waste transport containers and radioactive decommissioning waste container loading arrangement (plan) were evaluated during the design life period (year 2034). First, as only the IP-2 type transport container with a weight of 7.5 tons and size of 1.6 m (W) × 3.4 m (L) × 1.2m (H) can be loaded in the cargo hold, if only the decommissioning radioactive waste containers are to be loaded and transported, cargo hold needs to be reinforced. Second, when both the radioactive decommissioning waste transport container of the same size as the current operating radioactive waste transport container, and the radioactive decommissioning waste transport container of the same size as the ISO-type transport container are to be loaded in the cargo hold of the CHEONG-JEONG-NURI and transported, the overall design changes (cargo hold size and load reinforcement) are required. Third, since the safe working load of the CHEONG-JEONG-NURI crane is 12.5-tons, it shall be replaced with a ship crane of 35-tons or more to handle the decommissioning radioactive waste container smoothly, or a gantry crane used in general port facilities shall be installed. When replacing with a ship crane of 35-tons or more, ship buoyancy, ship stability, and ship structural safety shall be considered. The possibility of moving in all 4 directions for smooth operation, and the possibility of lifting the transport container to a position higher than the height of the CHEONG -JEONG-NURI shall be considered. Loading and transporting all decommissioning radioactive waste containers, which are the same size as IP-2 and ISO-type transport containers, in the cargo hold of the CHEONG-JEONG-NURI is uneconomical due to the need for overall design changes (cargo size and load reinforcement, etc.). Also, delay in delivery of the operation wastes is expected due to a long-term design change period. Therefore, it is considered reasonable to load and transport only the decommissioning radioactive waste transport container, which is the same size as the IP-2 transport container, in the cargo hold.

In preparation for the decommissioning of Kori unit 1 of the nuclear power plant (NPP), new containers of package, transportation, and disposal are being developed that reflect the type, generation amount, and radiological characteristics of decommissioning waste. The containers under development have internal volumes of 1 m3 ~ 14 m3 and loading weights of 1 ton ~ 35 tons, which are larger in size and have a higher loadable weight compared to the 200 L drum and IP-2 type transport container currently being used for packaging and transporting waste. So, there is a limit to handling new containers using existing transport systems (cranes, spreaders, forklifts, transport vehicles, etc.). Therefore, in this study, the status of handling equipment in NPP and disposal facilities was reviewed, the flow from the generation to disposal of decommissioning waste was analyzed, and the possibility of handling new container or the necessity of introducing new systems were derived. Except for some high-dose/high-radioactive wastes among decommissioning wastes, all wastes are finally disposed of through decommissioning area, temporary storage facility, waste treatment facility, waste storage facility, and receipt and storage building. The decommissioning area, temporary storage facility, and waste treatment facility are newly established areas for the decommissioning and should be equipped with a spreader/crane with a lifting weight of 15 tons, 35 tons, and 40 tons in consideration of the weight of the package to be handled in the zone. The waste storage facility has a 7.5 tons crane, so it can handle only some of the lower weight of the 5 to 35 tons package that is expected to be handled. Therefore, additional installation of spreaders/cranes, each with a lifting capacity of 15 tons and 40 tons, is required. The maximum loading weight of forklifts and transport vehicles operating at NPP, and disposal facilities is 10 tons and 12.6 tons, respectively. To transport the package, the facility must additionally install 15 tons and 40 tons forklifts, and 40 tons transport vehicles. Since the lifting weight of the crane installed on the transport vessel is also low at 12.5 tons, it is necessary to change the design of the existing or replace it with 40 tons to handle high-weight package. The results of this study will be used as basic data for the establishment of transport systems in the relevant area and facility, and design requirements for each equipment will be derived through additional research.

The design life of the radioactive waste carrier, the CHEONG JEONG NURI, is in the year 2034, when the decommissioning of Kori Unit 1 is expected. As only IP-2 type transport containers (7.5- tons, 1.6 m (W) × 3.4 m (L) × 1.2 m (H)) can be loaded onto the CHEONG-JEONG-NURI, the radioactive decommissioning waste (RDW) transport containers neither of 35-tons maximum weight nor ISO type can be accommodated. Accordingly, either a new vessel (NV) to replace the CHEONGJEONG- NURI or a change in the loading dock design of the CHEONG-JEONG-NURI is required. In this study, the necessity of building a NV capable of accommodating the issued containers above is analyzed focusing, (1) the estimated building and operating costs of the NV, and (2) the economic feasibility of the NV ‘s RDW transportation scenarios. Among bulk carriers, the CHEONG-JEONG-NURI was designed as handy-size ship type. It is operated reflecting various design requirements to satisfy the domestic/international legal requirements. To estimate the cost of the NV, the same vessel type and design criteria of the CHEONG-JEONGNURI were considered. The shipping price information of the Korea Ocean Business Corporation, as of August 2022, the building cost of bulk carrier Handysize (building NV type) is about USD 30 million. Considering domestic/overseas variables, such as future labor costs, international inflation, interest rate hike, etc., the building costs are expected to continuously rise. Furthermore, vessel operation costs of crew labor, vessel, fuel, and insurance are incurred separately. Due to the increase in oil price, and wages of special positions, such as general seafarers and radiation safety managers, the NV’s operating cost is expected to be about KRW 3.8 billion every year, which is about KRW 1.1 billion higher than that of the CHEONG-JEONG-NURI. The expected total cost of building and operating the NV is about KRW 65 billion. Assuming the repayment period of the NV building cost is the same as that of the CHEONG-JEONG-NURI building cost reimbursement agency and analyzing the economic feasibility of the transport scenario of the NV built by adding up about KRW 3.8 billion of the operating cost, cost about KRW 880 million per voyage of the NV built is expected, which being KRW 620 million more than the current cost (KRW 260 million) per trip of the CHEONG-JEONG-NURI. Therefore, transporting the RDW to the disposal facility through sustainable use of the CHEONGJEONG- NURI (considering design life extension and design change) is evaluated as more appropriate than building NV.