The damage to structures during an earthquake can be varied depending on the frequency characteristics of seismic waves and the geological properties of the ground. Therefore, considering such attributes in the design ground motions is crucial. The Korean seismic design standard (KDS 17 10 00) provides design response spectra for various ground classifications. If required for time-domain analysis, ground motion time series can be either selected and adjusted from motions recorded at rock sites in intraplate regions or artificially synthesized. Ground motion time series at soil sites should be obtained from site response analysis. However, in practice, selecting suitable ground motion records is challenging due to the overall lack of large earthquakes in intraplate regions, and artificially synthesized time series often leads to unrealistic responses of structures. As an alternative approach, this study provides a case study of generating ground motion time series based on the hybrid broadband ground motion simulation of selected scenario earthquakes at sites in the Nakdonggang delta region. This research is significant as it provides a novel method for generating ground motion time series that can be used in seismic design and response analysis. For large-magnitude earthquake scenarios close to the epicenter, the simulated response spectra surpassed the 1000-year design response spectra in some specific frequency ranges. Subsequently, the acceleration time series at each location were used as input motions to perform nonlinear 1D site response analysis through the PySeismoSoil Package to account for the site response characteristics at each location. The results of the study revealed a tendency to amplify ground motion in the mid to long-period range in most places within the study area. Additionally, significant amplification in the short-period range was observed in some locations characterized by a thin soil layer and relatively high shear wave velocity soil near the upper bedrock.

PURPOSES : This study aimed to analyze the primary maintenance procedures and safety inspection checklist characteristics for suspension bridges. The study referred to the current suspension bridge safety management manual and conducted an on-site safety inspection. By comparing and analyzing any missing or inadequate inspection and management procedures, the study identified major inspection and management areas requiring improvement, and proposed potential solutions. METHODS : The study referred to the current suspension bridge safety management manual and conducted on-site safety inspections. By comparing and analyzing any missing or inadequate inspection and management procedures, the study identified major inspection and management areas requiring improvement, and proposed potential solutions. RESULTS : The study found that suspension bridges are currently inefficiently managed compared to other facilities subject to more rigorous maintenance and safety inspection. Therefore, maintenance and safety inspection procedures require improvement. CONCLUSIONS : For effective safety management and to reduce potential accident risk factors arising from negligent management, major improvements were suggested. Scientific maintenance and safety management could be achieved by incorporating enhancements into statutory requirements and improving management and inspection procedures. This long-term approach is likely to be more economical than the current methods, which lead to higher maintenance and repair costs and increased social costs from traffic accidents.

Animal bones excavated from historic sites provide valuable data for identifying the lifestyles of people and the distribution of animals at that time. In this study, we investigated the morphological structure, size, and measurements of Cervidae bones excavated from a well at the Gasan-ri archaeological site in Jinju, which are believed to be relics from the Three Kingdoms period. The total number of excavated animal bones was 447, of which 102 (22.82%) were classified as Cervidae bones. The weight of Cervidae bones was 453.79 g, accounting for 46.53% of the total weight of the identified bones (975.30 g). The Cervidae bones were identified as those of two animals with an estimated age of 5–6 months. The Cervidae bones are divided into skull bones, vertebrae, ribs, sternum, hip bones, forelimb bones, and hindlimb bones. The 102 Cervidae bones consisted of 19 skull bones (18.63%), 14 vertebral axial skeletons (13.72%), 28 ribs and sternum (28.43%), 16 forelimb bones (15.69%), and 19 hindlimb bones (18.63%). The remaining six were difficult to distinguish. A fracture of the parietal bone located near the bregma of a skull was observed and was presumed to have been caused by an artificial blow. This study can be used as basic data to estimate the types of animals and human culture at the time through Cervidae bones believed to be relics from the Three Kingdoms period.

국내 중·저준위 방사성폐기물은 영구적 격리를 위해 처분장에 매립하고 있으며 그 위치는 경주에 있다. 이러한 방 사성폐기물의 영구적인 격리를 위한 처분시설은 공학적 방벽과 자연 방벽으로 구성되어 있으며 자연 방벽을 특성을 파악 하기 위하여 한국원자력환경공단에서는 2006년부터 부지특성조사를 수행하였고, 이후 부지감시 및 조사계획에 따른 감시 를 수행하여 부지특성의 변화를 지속적으로 확인하고 있다. 중저준위 방폐장의 수리지화학적 환경은 자연 방벽의 평가를 위해 중요한 요소로 손꼽히고 있으나 동해와 가까운 경주의 지역적 특성상 해수의 영향을 반드시 고려해야 한다. 따라서 본 연구에서는 처분 부지의 지하수 관정 7개 및 관정의 심도별 수질 자료를 취합해 지하수 자료 총 30개를 해수 2개소와 비교 분석하여 수리지화학적 환경을 해석하였다. 분석 자료는 수질 10개 항목(온도, EC, HCO3, Na, K, Ca, Mg, Cl, SO4, SiO2)을 2017년 3분기부터 2022년 3분기까지 총 5년간 20회의 자료를 활용하였다. 특히, EC, HCO3, Na, Cl의 농도 변화 를 통해 연구 지역의 배경 농도 및 관정의 구간별 해수의 영향을 파악하였으며, 시계열 군집 분석을 통해 담수, 기수, 해 수의 분류를 시도하였다. 그 결과, 기존의 모니터링 방법으로는 확인하지 못한 부지내 수리지화학적 변화를 제시하였다.

Long-term climate and surface environment changes can influence the geological subsurface environment evolution. In this context, a fluid flow pathway developing and connection possibility can be increased between the near-surface zone and deep depth underground. Thus, it is necessary to identify and prepare for the overall fluid flow at the entire geological system to minimize uncertainty on the spent nuclear fuel (SNF) disposal safety. The fluid flow outside the subsurface environment is initially penetrated through the surface and then the unsaturated area. Thus, the previously proved reports, POSIVA in Finland, suggested that sequential research about the fluid infiltration experiment (INEX) and the investigation is necessary. Characterizing the unsaturated zone can help predict changes and ensure the safety of SNFs according to geological long-term evolution. For example, the INEX test was conducted at the upper part of ONKALO, about 50 to 100 m depth, to understand the geochemical evolution of the groundwater through the unsaturated zone, to evaluate the main flow of groundwater that can approach the SNF disposal reservoir, and to estimate the decreasing progress of the buffering capacity along the pathway through the deep geological disposal. In the present study, a preliminary test was performed in the UNsaturated-zone In-situ Test (UNIT) facility near the KAERI underground research tunnel to design and establish a methodology for infiltration experiments consistent with the regional characteristics. The results represented the methodological application is possible for characterizing unsaturated-zone to perform infiltration experiments. The scale of the experiment will be expanded sequentially, and continuous research will be conducted for the next application.

The KINAC resident inspectors are responsible for conducting on-site regulatory and intergovernmental support tasks related to safeguards, physical protection, and cybersecurity in each NSSC regional office. In nuclear material accounting and control, resident inspectors primarily perform tasks such as national inspections and technical support for IAEA inspections. However, with the increasing cases of non-compliance with the advance notification procedure by operators, there is a growing need for improvement in the role of resident inspectors in on-site regulation. In response to this situation, the safeguards division in KINAC has analyzed and improved the on-site check procedures of resident inspectors at LWR facilities. The existing procedure outlines the process where resident inspectors receive the advance notification documents submitted by operators and utilize them as a reference for conducting weekly checks during the overhaul period when IAEA surveillance cameras are installed. Additionally, according to the attached forms specified in the procedure, resident inspectors are required to submit the check results report to the director of the safeguards division in KINAC every week and to the NSSC every month. The inspection items include checking the execution and changes of advance notification, verifying unnotified matters, discussing other issues, assessing the integrity of things such as the operational status of IAEA surveillance equipment, and so on. On April 13-14, 2023, the Safeguards division organized a two-day resident inspector’s work-sharing workshop to discuss improvements in the on-site check procedures of resident inspectors at LWR facilities. During the workshop, a comparison and analysis were conducted between the existing procedures and actual on-site activities. Unnecessary tasks such as advance notification document reception and monthly reporting were eliminated, and the focus was shifted towards emphasizing essential tasks. The opinions of resident inspectors were taken into account to derive directions for improvement. The existing procedure was applicable only during Overhaul periods for resident inspectors. It has been improved by removing this limitation, allowing its use during routine times. Furthermore, the procedure has been enhanced by clarifying its purpose, scope, users, and definitions of terms and specifying responsibilities and authorities. Unnecessary terminology has been eliminated. Remarkably, the definition of advance notification has been detailed, and the reporting of check results has been simplified through weekly task reporting. The Safeguards division in KINAC has strived to enhance the efficiency and simplification of on-site regulatory activities for resident inspectors at LWR facilities by improving their on-site check procedures. These improvement activities are expected to aid resident inspectors in effectively performing a wide range of tasks, including safeguards, physical protection, cybersecurity, and government support. In the future, it will be possible to continue refining the on-site check procedures by sharing the results of using the procedure in meetings and gathering various opinions from resident inspectors.