과거 지진 발생 시 구조요소에 비해 비구조요소에서 더 많은 피해가 발생하였다. 비구조요소의 손상은 건물 및 시설의 기능에 영향을 줄 뿐만 아니라 인명피해를 유발할 수 있다. 건축물 내진설계 기준에서는 피난경로상의 비구조요소는 내진설계 또는 검토가 필요하다. 국내에서는 경주지진 이후 피난경로에 위치할 수 있는 천장 시스템의 내진성능 검증이 활발히 진행되고 있다. 그러나 옥외 계단, 문 등에 설치되는 캐노피 시스템의 내진설계 및 검증은 미흡한 실정이다. 지진으로 인해 캐노피가 위치유지를 하지 못하여 탈락 하거나 손상될 경우, 피난경로가 차단되어 인명피해로 이어질 수 있으므로 내진설계 및 내진성능을 평가할 필요가 있다. 따라서 본 연구에서는 모듈형 캐노피 시스템을 개발하고, 주요 요소에 대한 구조실험을 수행하였으며, 기존의 캐노피 시스템과 그 성능을 비교분 석 하였다.

In this study, the strength properties of recycled plastic materials using polypropylene, polyethylene, and high-density polyethylene were evaluated by measuring their compressive and flexural strengths, which are typically measured in cement-concrete pavements, to assess the feasibility of using recycled plastic materials as construction materials for modular pavements that can easily integrate advanced sensors, such as those for future autonomous driving. Two types of recycled plastic (composite resin and high-density polyethylene (HDPE)) and two types of inorganic materials (fly ash and limestone filler) were selected to evaluate the strengths of recycled plastic materials. Specimens for the compressive and flexural strength tests were prepared with four different recycled plastic contents (100%, 80%, 60%, and 40%). The compressive and flexural strengths of the recycled plastic specimens were measured according to the KSL ISO 679 and KSL 5105 methods, and the strength properties were analyzed based on the type and content of the recycled plastic and type of inorganic material used. Distortion and shrinkage problems were observed during specimen preparation using the 100% recycled plastic material. This indicated that inorganic materials must be incorporated to improve the flexural strength and facilitate specimen preparation. The compressive strength of plastic materials was comparable to the 28-day compressive strength of conventional cement-concrete pavements. The compressive strength of the composite resin was approximately twice that of HDPE. The flexural strengths of both the composite and HDPE were in the range of 15–25 MPa, suggesting their suitability as materials for the construction of modular pavement structures. Based on the limited strength test results, we can conclude that the strength properties of recycled plastic materials are similar to those of conventional cement-concrete paving materials. From the strength perspective, we confirmed that recycled plastic materials can be utilized as construction materials for modular pavements. However, further research should be conducted on factors such as molding methods for modular pavement structures based on different types of recycled plastic materials.

In this article, to solve the problems about obsolescence of parts and unable to driving turret when internal components are failure, the DC-DC boost converter in the gun/turret drive system of mobile weapon was improved. The power converting circuit in converter is changed by applying the latest components, and the control circuit is changed from analog to digital. Also, the power converting circuits were modularized in three parallel so that it could be driven even when some components failed. The improved DC-DC boost converter secured stability such as converting to voltage in a linear manner in the entire section from the start of boosting to the end. Also, through the modular configuration, turret driving system can operates when some components failed.

지구온난화 문제에 대응하기 위해 온실가스 배출 저감을 위한 다양한 규제와 정책이 시행되고 있다. 이러한 배경 속에서 탄소중립을 목표로 하는 국가들이 늘어나고 있으며, 이에 따라 소형원자로모듈(Small Modular Reactor 이하 SMR)이 새로운 발전소 모델 로 주목받고 있다. SMR은 전통적인 대형 원자력 발전소 크기의 5~10% 수준이지만, 수백 메가와트(MW)급의 발전 용량을 갖춘 고효율 시스템이다. 이 발전소는 화석 연료 기반 발전소에 비해 탄소 발생을 줄일 수 있으며, 신재생에너지의 불안정한 에너지 공급을 보완할 수 있는 장점이 있다. 하지만, 원자력 발전소는 사고 시 방사선물질 누출의 위험성이 있어 주변 주민의 반대를 받아 왔다. 이러한 문제 를 해결하기 위해 부유식 소형 원자력 발전선이 주목받고 있다. 부유식 소형 원자력 발전소는 해양에 설치되어 부지확보, 인근 거주민 보상, 협의 과정이 간소화되고, 자연재해에 대한 안전성이 높다. 본 연구에서는 SMR 발전선의 파랑 중 예인 안정성을 평가 하였다. 해 상상태 3, 4, 5에서의 운동해석 결과, 해상상태 5 이하에서는 예인하여 목적지까지 이동하는데 필요한 내항성능 기준을 만족시킬 수 있 음을 확인하였다.

본 연구는 철도교 노후화에 따른 열차운행 중 신속 교체 및 재난·재해에 대한 급속 시공을 통하여 공기단축 및 시공성 확보로 국민의 사회적·경제적 피해를 최소화하고자 한다. 철도교 개량 등에서 필 수적인 8철도하로교 시공고도화 및 성능향상9을 위하여 신속 교체와 성능향상이 가능한 강합성 철도하 로교 설계·제작·시공 기술을 개발하고자 한다. 또한, 개발하고자 하는 강합성 하로교의 경우 철도교뿐 만 아니라 도로교에서 적용하고자 하며, 철도교는 상부구조가 단경간 형식으로 이루어지고 있어 철도 교 사용성 검토에 큰 문제가 없으나 도로교의 경우 바닥판 연속화를 고려 중에 있어, 이에 대한 온도 및 부모멘트 등 여러 문제점을 검토하였다. 상로교의 경우 다수의 거더에 의해 바닥판이 지지되므로 PS의 중요성이 부각될 수 없지만, 하로교의 바닥판은 양단 거더에 의한 고정지지이므로 RC구조 적용 이 어려워, 강합성 또는 PSC 공법을 일반적으로 적용한다. 기존 강합성 구조는 비용, 공기 측면에서 지양하고 PSC 구조의 가로보 및 바닥판과 강재 거더를 합성한 하로교를 개발하고자 한다.

The initial development plans for the six reactor designs, soon after the release of Generation IV International Forum (GIF) TRM in 2002, were characterized by high ambition [1]. Specifically, the sodium-cooled fast reactor (SFR) and very-high temperature reactor (VHTR) gained significant attention and were expected to reach the validation stage by the 2020s, with commercial viability projected for the 2030s. However, these projections have been unrealized because of various factors. The development of reactor designs by the GIF was supposed to be influenced by events such as the 2008 global financial crisis, 2011 Fukushima accident [2, 3], discovery of extensive shale oil reserves in the United States, and overly ambitious technological targets. Consequently, the momentum for VHTR development reduced significantly. In this context, the aims of this study were to compare and analyze the development progress of the six Gen IV reactor designs over the past 20 years, based on the GIF roadmaps published in 2002 and 2014. The primary focus was to examine the prospects for the reactor designs in relation to spent nuclear fuel burning in conjunction with small modular reactor (SMR), including molten salt reactor (MSR), which is expected to have spent nuclear fuel management potential.

Recently, as carbon-neutral energy sources become increasingly important worldwide, SMRs (Small Modular Reactors), which offer significantly enhanced safety, versatility, and mobility compared to conventional nuclear reactors, are gaining attention as a viable alternative. SMR generally refers to small modular reactors with a power output of 300 MWe or less. Unlike conventional reactors, SMRs are characterized by an all-in-one design where peripheral systems and equipment are all integrated into the reactor itself, leading to enhanced reliability and durability. Additionally, the nuclear fuel reloading cycle is significantly extended compared to traditional reactors, resulting in a substantial reduction in maintenance difficulty and costs. Researchers have taken note of these characteristics of SMRs, particularly the extended fuel reloading cycle. Therefore, we have initiated the initial design of an ultra-small Micro Modular Reactor with an electricity generation capacity of 10 MWe and a fuel cycle of up to 55 years, with the goal of using it as a propulsion power source for various transportation modes, especially ships. Our design of MMR, called ‘ARA,’ is primarily distinguished by its use of U233 and Th232 fuels instead of conventional UO2 fuel. Due to various features of ‘ARA,’ including different fuel compositions, ARA is predicted to exhibit several characteristic features compared to conventional PWRs. In this study, among these characteristics, we focused on predicting changes in material composition within the fuel rod during the extended cycle operation of high-enriched fuel, rather than short-cycle operation using low-enriched fuel, unlike conventional reactors. The primary goal of this research is to observe the behavior of the composition of the materials used in the fuel cycle of the MMR, which utilizes U233 and Th232 fuels instead of UO2. Considering the difficulties in the spent nuclear fuel disposal process, many different trials were made to minimize the fission products of ARA, which differs from conventional reactors in terms of fuel type, size, and fuel cycle, in relation to waste generation.

The process basket assembly is an important module in pyroprocess, because pyroprocess is a batch process, so process materials are contained in a basket assembly and transferred with the basket. The basket assembly is composed of upper and lower assembly. The lower assembly is a basket or crucible which contains process materials, and it can have electrodes. The upper assembly mainly consists of heat shields, a flange, and connectors for supplying currents to electrodes of the lower assembly. During the electrolytic recovery process, the lower part is submerged into molten salt, whose temperature is about 500°C at least and the heat from salt is transferred to the upper assembly. And the heat affects the performance or durability of parts on the top of equipment and can raise cell temperature, which is an undesired situation. In addition, the handling equipment can pick the assembly when it is hottest, and during the transfer, the gripped part is under thermal and mechanical stresses. Because of this, the thermal effects from the heat should be required during equipment design stage. In this study, the thermal analyses of process basket assembly were conducted for 3 cases: the steady state of the basket assembly when it submerged in molten salt, the thermal and mechanical stresses when gripped by remote handling device, and the temperature changes under natural convection. These analyses were performed using Solidworks with flow simulation package, and the results will apply to improve the thermal resistant performance of the basket assembly.

Modular construction is an economical and efficient construction that reduces time and costs by manufacturing units in factories and constructing them on site. Currently, the demand for modular construction is increasing not only abroad but also domestically. As the demand for modular construction increases, a lot of development and research on connections between modular units are being conducted. Connections between modular units should be quick and simple to assemble when assembling units on site, and should be in a form that allows each unit to be connected regardless of direction. In addition, it must be able to exert sufficient strength against external loads. In this study, a connection between modular units using connecting steel plates and bolts was proposed, and the nonlinear behavior of the connection to external lateral force was analyzed through finite element analysis, and resistance performance was evaluated.