It is important that the plasma torch used in the waste treatment field has a high output to increase throughput. In order to increase the output of the plasma torch, there is a method of increasing the current or extending the length of the plasma arc. Among these methods, high power can be easily achieved simply by increasing current, but it is difficult to ensure electrode life. Therefore, it is necessary to check the appropriate current and arc length conditions to achieve high power and stable operation. In this paper, the power performance according to the arc length, current, and operation mode was confirmed in the transfer mode plasma torch. The test conditions are the distance (arc length) between the plasma torch and the external electrode was set to 5-180 mm, and the current was set to be in the range of 90-460 A. As a result of the test, it was confirmed that the reverse polarity operation had a maximum output of 159 kW depending on the arc length and current, and the positive polarity operation had a maximum output of 138 kW. Through this result, it was confirmed that the arc length had an effect on increasing the output, and that the reverse polarity operation had a longer arc than the positive polarity operation.

A plasma torch is a kind of equipment that utilizes an electric arc to dissociate a gas and transfer an electric energy to the gas to generate very high temperature flame. KHNP-CRI has been developed the Plasma Torch Melter (PTM) to reduce radioactive waste disposal volumes and drop the radiation level of wastes. As you guess, there is required condition for proper start-up operation like current, voltage, plasma gas flow, cooling water flow, temperature in melter and so on. Thus, the optimum start-up operation condition of plasma torch will be estimated experimentally in this paper.

As if the wet storage of Spent Nuclear Fuel (SNF) becomes saturated, a transition from wet storage to dry storage could be required. The first process for dry storage is to move SNF from the wet storage into a canister for dry storage, and secondly perform a drying process to remove the moisture in the canister to prevent a potential impact such as deterioration of cladding or corrosion of the interior material. Nuclear Regulatory Commission (NRC) accepts the conditions describing the adequate dryness state that remain below the pressure of 3 Torr for 30 minutes in the drying process. That is, the most pressure of water vapor that may exist inside the canister is 3 Torr. If it is maintained below 3 Torr, it can be determined that the dryness criterion is satisfied. Based on this, relative humidity and dew point trends can be identified. Relative Humidity (RH) is calculated by dividing the vapor pressure by the saturated vapor pressure. Here, if the vapor pressure is fixed at 3 Torr, which is the dryness criterion value, the relative humidity has a value according to the saturated vapor pressure. Saturated vapor pressure is a value that varies with temperature, so relative humidity varies with temperature. On the other hand, the dew point temperature has a value according to the water vapor pressure. Therefore, when the internal temperature of the canister is 120°C and the water vapor pressure is 3 Torr, the relative humidity is 0.2% and the dew point temperature is -4.4°C. We will confirm the suitability of the dryness criterion through the drying tests, and secure a technology that can measure and evaluate the amount of moisture remaining inside the canister.

Although it is highly dependent on the production of coastal and offshore fishing, the Fishing Vessels Safety Fisheries Act was enacted in 2019 due to the continuous increase in marine accidents of coastal and offshore fishing vessels. However, the law is too focused on fishing and navigation in certain waters and does not contain accident-preventive content. Ministry of Oceans and Fisheries proposes a plan to revise the Fishing Boat Safety Fishing Act through legal comparison with Japan's Seafarers' Labor Sanitation Rules. It also proposes an amendment that includes the content of the Seafarers Act on post-accident action obligations. Under the Fishing Vessels Safety Fishing Act, the safety fishing education is implemented for specific people and adopts a method of delivery education after completing the education. The reason for this is that the educational requirements are not sufficient compared to the number of education personnel. Moreover, four hours of education are conducted once a year, which is not suitable for insufficient educational conditions. For efficient safety fishing education, improvement measures are proposed compared to education in the United States and the United Kingdom.

The need for an intelligent information-based ship accident prevention and control system for various marine accidents is very clearly emerging. As it is a variety of marine accidents, the causes are diverse. Therefore, it can be said that it is very important to prevent these marine accidents and their causes in advance. Therefore, a study was conducted on an intelligent information-based ship safety management decision support system that provides information necessary for decision-making at sea and land through an integrated management device for ships that informs safety-related risks in real-time ship operation. In the future, we intend to pursue the development of a system that can aim for safer and more economical ship operation by linking it to navigation instruments through the evaluation and analysis of AI, IoT, and big data.

기상불량으로 인해 발생하고 있는 해양사고 중 해무 발생에 따른 시계제한은 선박의 좌초, 선저 파손 등의 사고를 유발하는 것과 동시에 사고에 따른 인명피해를 동시에 수반하고 있으며 이는 매년 지속적으로 발생하고 있다. 또한 해상에서의 저시정은 지역간 국소적으로 차이가 존재하는 경우에도 일괄적으로 여객선에 대한 운항 지연 및 통제 조치를 하고 있어 섬주민들의 교통수단 이용에 상당 한 불편을 초래하는 등의 사회적 문제로 대두되고 있다. 더욱이 이와 같은 조치는 지역적 편차나 사람마다 관측의 판단 기준이 상이하여 이를 객관적으로 정량화하지 못하고 있어 더욱 문제가 심화되고 있는 실정이다. 현재 각 항만의 VTS에서는 시정거리가 1km 미만인 경우 선박의 운항을 통제하고 있으며, 이 경우 저시정에 따른 해무 가시거리를 시정계 혹은 육안에 의한 목측(目測)에 의존하고 있을 정도로 객관적인 데이터 수집을 통한 평가에 있어서는 한계가 있다. 정부에서는 이와 같은 해양교통안전 저해요소를 해결하기 위한 일환으로 해 무 탐지 및 예측을 위한 해양기상신호표지 및 해상안개관측망을 구축하여 운용하고 있으나, 국지적으로 발생하는 해무를 관측하기 위한 시스템은 매우 부족한 현실적 어려움에 놓여있다. 이에 따라 본 논문에서는 해상에서의 저시정으로 인해 발생하고 있는 여러 사회적 문 제를 해결하기 위한 국내․외 정책동향에 대해 살펴보고, 이와 관련한 일반국민 및 현장 이해관계자의 인식 정도를 조사․분석하여 해무 에 따른 해상교통안전을 확보하기 위한 정부지원(해무 탐지 및 예측 기술을 기반으로 한 해상교통운영 체계 개발 등)의 필요성에 대한 기 초자료를 제공하고자 한다. 또한 이는 궁극적으로 해무로 인해 발생할 수 있는 해상안전 위험요소를 사전에 차단함으로써 보다 안정된 해상교통운영체계를 마련하는데 그 목적을 두고 있다.

In an automotive plant, an automated storage and retrieval system (ASRS) synchronizes material handling flows from a part production line to an auto-assembly line. The part production line transfers parts on small-/large-sized pallets. The products on pallets are temporarily stored on the ASRS, and the ASRS retrieves the products upon request from the auto-assembly line. Each ASRS aisle is equipped with narrow-/wide-width racks for two pallet sizes. An ASRS aisle with narrow-/wide-width racks improves both storage space utilization and crane utilization while requiring delicate ASRS aisle design, i.e., the locations of the narrow-/wide-width racks in an ASRS aisle, and proper operation policies affect the ASRS performance over demand fluctuations. We focus on operation policies involving a common storage zone using wide-width racks for two pallet sizes and a storage-retrieval job-change for a crane based on assembly-line batch size. We model a discrete-event simulation model and conduct extensive experiments to evaluate operation policies. The simulation results address the best ASRS aisle design and suggest the most effective operation policies for the aisle design.

본 연구에서는 동명대학교 조선해양시뮬레이션센터의 Real-time 조종 및 작업 시뮬레이터를 활용한 해양구조물 설치 작업 시뮬 레이션을 통해 대상의 동적 특성 및 물리적 현상을 작업, 조종 사이의 상호 영향과 함께 분석한다. 8개의 계류삭에 의해 계류되는 반잠수 식 시추선의 설치 작업 시뮬레이션이 실제 현장에서의 작업과 유사한 시나리오로 수행되었고, 시추선의 위치 제어를 위한 예인선 4척와 계류삭의 Hook-up 작업을 위한 해양플랜트 지원 선박 1척이 운용되었다. 설치 작업이 수행되는 동안 대상들의 운동과 이동 경로, 계류삭 및 예인줄에 가해지는 장력 등을 실시간으로 확인하였으며, 이를 작업 과정별로 구분하여 분석하였다. 작업과 조종 시뮬레이션이 동시에 수행된 본 연구로부터 특정 환경 외력하에서 설치되는 해양구조물과 이를 위해 운용되는 선박들의 작업 절차에 따른 세부적인 거동 및 작업·조종 간의 상호 영향을 확인하였고, 이는 해상 상태 등을 고려한 해양구조물 설치 작업의 수행 가능 여부를 판단하기 위한 근거로 활용될 수 있음을 제시하였다.

Complaints about foul odors are emerging as an issue, and the number of complaints is steadily increasing every year. Biofiltration is known to remove harmful or odorous substances from the atmosphere by using microorganisms, and full-scale biofilters are being installed and operated in various environmental and industrial facilities. In this study, the current status and actual odor removal efficiency of full-scale biofilters installed in publicly owned treatment facilities such as sewage, manure, and livestock manure treatment plants were investigated. In addition, the effects of design and operating factors on their efficiency were also examined. As a result, it was found that odor prevention facilities with less than 30% odor removal efficiency based on complex odors accounted for 40%-50% of the biofilters investigated. In investigating the appropriate level of operating factors on odor removal efficiency, it was found that compliance with the recommended values p lays a significant role in improving odor removal efficiency. In the canonical correlation analysis for the on-site biofilter operation and design data, residence time and humidity were found to be the most critical factors. The on-site biofilter operation and design data were analyzed through canonical correlation analysis, and the residence time and humidity maintenance were found to be the most important factors in the design and operations of the biofilter. Based on these results, it is necessary to improve the odor removal efficiency of on-site biofilters by reviewing the effectiveness of the operation factors, improving devices, and adjusting operating methods.