Nuclear power plants, which are important national facilities, require special attention against the threat of terrorism using various methods. Among the terrorist threats, as structural damage and human casualties due to explosions continue to occur, interest in the blast load is increasing. However, domestic nuclear power plants do not have sufficient design requirements for protection against the threat of explosives. To prepare for the threat of terrorism using explosives, it is necessary to evaluate the physical protection performance of nuclear power plants against blast load, and to use this to improve protection performance and establish regulatory standards. Most of the explosion-proof designs used abroad use the empirical chart presented by UFC 3-340- 02 (DoD 2008), which does not take into account the effect of near-field explosions. When explosions occur inside nuclear power plants, near-field explosions occur in most cases. In this study, it was assumed that explosives were installed in the corridor inside nuclear power plants. A spherical TNT was placed in the middle of the corridor floor to simulate near-field explosions, and the structure response according to the weight of the TNT was evaluated. The corridor was modeled with a reinforced concrete material and the LS-DYNA program was used for analysis. For the explosion model, the Arbitrary-Lagrangian-Eulerian (ALE) analysis technique applying the advantages of the Lagrangian and Eulerian methods were used. By analyzing the pressure history and the degree of deformation of the structure according to the explosion, the degree of threat caused by the explosion was analyzed. Based on the analysis of this study, physical barriers performance database (DB) using Modeling & Simulation (M&S) will be constructed by performing sensitive analysis such as representative structure shape setting, boundary conditions, material of structures, etc. The constructed DB is expected to be used to establish regulatory standards for the physical barriers of nuclear power plants related to explosives.

Operating and decommissioning nuclear power plants generates radioactive waste. This radioactive waste can be categorized into several different levels, for example, low, intermediate, and high, according to the regulations. Currently, low and intermediate-level waste are stored in conventional 200-liter drums to be disposed. However, in Korea, the disposal of intermediate-level radioactive waste is virtually impossible as there are no available facilities. Furthermore, large-sized intermediate- level radioactive waste, such as reactor internals from decommissioning, need to be segmented into smaller sizes so they can be adequately stored in the conventional drums. This segmentation process requires additional costs and also produces secondary waste. Therefore, this paper suggests repurposing the no-longer-used spent nuclear fuel casks. The casks are larger in size than the conventional drums, thus requiring less segmentation of waste. Furthermore, the safety requirements of the spent nuclear fuel casks are severer than those of the drums. Hence, repurposed spent nuclear fuel casks could better address potential risks such as dropping, submerging, or a fire. In addition, the spent nuclear fuel casks need to be disposed in compliance with the regulations for low level radioactive waste. This cost may be avoided by repurposing the casks.

Nuclear power plant decommissioning generates significant concrete waste, which is slightly contaminated, and expected to be classified as clearance concrete waste. Clearance concrete waste is generally crushed into rubble at the site or a satellite treatment facility for practical disposal purposes. During the process, workers are exposed to radiation from the nuclides in concrete waste. The treatment processes consist of concrete cutting/crushing, transportation, and loading/unloading. Workers’ radiation exposure during the process was systematically studied. A shielding package comprising a cylindrical and hexahedron structure was considered to reduce workers’ radiation exposure, and improved the treatment process’s efficiency. The shielding package’s effect on workers’ radiation exposure during the cutting and crushing process was also studied. The calculated annual radiation exposure of concrete treatment workers was below 1 mSv, which is the annual radiation exposure limit for members of the public. It was also found that workers involved in cutting and crushing were exposed the most.

Major accidents at nuclear power plants generate huge amounts of radioactive waste in a short period of time over a wide area outside the plant boundary. Therefore, extraordinary efforts are required for safe management of the waste. A well-established remediation plan including radioactive waste management that is prepared in advance will minimize the impact on the public and environment. In Korea, however, only limited plans exist to systematically manage this type of off-site radioactive waste generating event. In this study, we developed basic strategies for off-site radioactive waste management based on recommendations from the IAEA (International Atomic Energy Agency) and NCRP (National Council on Radiation Protection and Measurements), experiences from the Fukushima Daiichi accident in Japan, and a review of the national radioactive waste management system in Korea. These strategies included the assignment of roles and responsibilities, development of management methodologies, securement of storage capacities, preparation for the use of existing infrastructure, assurance of information transparency, and establishment of cooperative measures with international organizations.

블록 매칭 및 3D 필터링(BM3D) 알고리즘은 단일 필터의 문제점을 보완하기 위하여 non-local means 기반으로 만들 어진 융합형 노이즈 제거 알고리즘이다. 하지만, 그 수식 인자의 조절에 관한 연구는 이루어지지 않고 있어 본 연구에서는 자기공명영상에서 발생하는 Rician 노이즈를 제거하기 위해 BM3D 알고리즘의 평활화 정도를 결정하는 노이즈 전력 스펙 트럼 밀도(noise power spectrum density,  )에 대한 최적화를 진행하고자 하였다. MRiLab 시뮬레이션 프로그램을 이 용하여 뇌 조직을 모사할 수 있는 뇌척수액(cerebrospinal fluid, CSF)/회색질(gray matter, GM)/백질(white matter, WM) 팬텀의 T1 강조영상을 획득하였고, 노이즈 레벨이 0.1, 0.15, 0.2, 0.25, 그리고 0.3인 Rician 노이즈를 각각 부가 한 후, BM3D 알고리즘의  값을 0.01부터 0.99까지 0.01씩 증가시키며 각각의 노이즈가 부가된 영상에 적용하였다. 정량 적 평가를 통해 최적화 값을 선정하기 위하여 CSF, GM, WM, 그리고 배경 영역에 관심 영역을 설정한 후 조직별 신호 대 잡음비(signal to noise ratio, SNR), 총 변동계수(coefficient of variation, COV), 그리고 평균 제곱근 오차(root mean square error, RMSE)를 측정하였다. 결과적으로, 조직별로 계산된 SNR, COV, 그리고 RMSE를 종합적으로 평가 했을 때 모든 조직에서 노이즈 레벨 0.1부터 0.3까지 증가함에 따라  값 또한 함께 증가하는 경향이 나타났으며 일정  값 이상에서는 노이즈뿐만 아니라 영상신호까지 함께 제거되어 개선 폭이 감소하는 것으로 관찰되었으며, 노이즈 레벨에 따라 각각 0.09, 0.13, 0.17, 0.21, 그리고 0.25의  값이 설정된 BM3D 알고리즘이 적용되었을 때 가장 합리적인 영상 특성을 보이는 것으로 나타났다. 결론적으로, 효과적인 노이즈 제거를 위해서 고정된 값이 아닌 노이즈 레벨에 따른 적합한 값을 적용해야 함을 증명할 수 있었다.

While protecting its lives and property from natural disasters such as floods and droughts, North Korea needs to develop into an informationized industrial society by securing renewable energy power in the era of energy transition. In addition, existing research has considered that a policy of continuous and consistent expansion of renewable energy based on the safety of the lives of ordinary people could be the solution. South Korea needs to recognize that the supply of energy for a minimum of living is more important to the North Korean people than the economic benefits of securing North Korea's renewable energy market. Therefore, in this paper, from that point of view, we have calculated the amount of electricity that North Korea lacks necessary for the lives of its inhabitants that can be replaced by renewable energy, and considered ways to estimate the market value.

In order to conduct a study on the importance of the wrist joint, which causes a lot of pain among middle-aged people, in relation to work related to musculoskeletal disorders, the effect of stretching on grasping power was studied. In order to compare the grasping power of the wrist for middle-aged people in their 50s, the experiment was conducted by comparing before and after the wrist joint motion stretching. According to the experimental results of wrist gripping power for the control group and the experiment group on wrist gripping power, it was investigated that stretching did not change much in increasing wrist gripping power, but stretching application had an effect on wrist gripping power. In terms of preventing musculoskeletal accidents, reducing pain due to degenerative diseases, and preventing accidents, stretching seems to have an effect when approaching, so it is considered that continuous stretching before and after work is necessary. Therefore, it is suggested that stretching time secured quantitatively through safety and health education before work is necessary.

In assessing the seismic safety of nuclear power plants, it is essential to analyze the structures using the observed ground motion. In particular, spatial variation in which the characteristics of the ground motion record differ may occur if the location is different within the site and even if the same earthquake is experienced. This study analyzed the spatial variation characteristics of the ground motion observed at the structure and site using the earthquake records measured at the Hamaoka nuclear power plant. Even if they were located on the same floor within the same unit, there was a difference in response depending on the location. In addition, amplification was observed in Unit 5 compared to other units, which was due to the rock layer having a slower shear wave velocity than the surrounding bedrock. Significant differences were also found in the records of the structure’s foundation and the free-field surface. Based on these results, the necessity of considering spatial variation in the observed records was suggested.

In this study is a study to measure the section by voltage through the high integration of the circuit of the inspection equipment for the power supply circuit of semiconductor equipment. The experiment was conducted by increasing the -1.5∼4 voltage section by 0.5V. At this time, the tolerance was applied to ±0.1%+5mA. Although the voltage increased through the experiment, the accuracy of the measurement data did not change, and it was confirmed through this experiment that the null hypothesis(H0) was adopted in each section through the hypothesis test.

This paper proposes a solution to the out-of band oscillation signal and in-band low transmitter power output that occurrs during the low-temperature operation test for the new mine detector GPR signal transmission and reception module. Tests were performed by applying the optimal values of capacitors and inductors through circuit analysis simulation under the limited space, as a result, it was confirmed that the gain and return loss were improved at all-band thereby preventing oscillation signal and low transmitter power output.

In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.

With the continuous prosperity and development of the marine industry, the number of ships is increasing while greenhouse gas emissions are rising. In order to meet the relevant international ship emission regulations, the solution of developing electric ships is proposed. As the core device of the electric ship propulsion system, the maturity and applicability of power battery technology play a key role in the development of the electric ship. This article introduces the principles and advantages of the fuel cell, lithium-ion battery as well as supercapacitor battery, respectively, and analyzes the application status and challenges of power batteries in existing electric ships. The development direction and problems to be solved of power battery in current and future ship applications are put forward, which can provide a reference for further research.

EPS(Electric Power Steeing) has been a popular system in the automotive industry since 2000 after the technology and safety was validated. The Korean Refrigerated Carts like Hankook Yogurt Coco was developed for the first time in the world. However this carts system and other small tranporting carts has no EPS. Thus the drivers of carts needed a EPS to avoid the burden when steeing a big weighted cart with 750Kgf as many women drivers complain the pain on their shoulders. This paper describes the application of EPS on Korean refrigerated carts with simulation results and experimental data shows the improvement of steering efforts.

일반적으로 혼자서 보내는 시간이 많을수록 외로움 수준이 높은 경향이 나타난다. 그러나 홀로 있을 때, 즉 사회적 으로 고립되었을 때 외로움을 경험하는지 여부는 사람마다 다르다. 본 연구에서는 홀로 많은 시간을 보내는 사람 중, 누가 외로움을 경험하는지를 예측하는 요인으로 권력감(sense of power)의 역할을 알아보았다. 연구 1은 대규모 설문 조사 연구 자료를 이용하여 사회적 시간이 적은 사람들의 외로움을 예측하는 요인을 알아보았다. 판별분석 결과, 권력 감이 사회적 활동 시간이 적은 사람들을 높은 외로움과 낮은 외로움 집단으로 판별하는 요인임을 검증하였다. 연구 2는 실험을 통해 권력감의 수준을 조작하여 높은 권력감과 낮은 권력감 집단으로 나누었다. 이후 홀로 있음을 점화한 뒤, 외로움과 소속감 상실의 여부가 권력감 조건에 따라 달라지는지 분석하였다. 그 결과 권력감이 높으면 사회적 외 로움을 적게 경험하고 소속감 상실이 완충되는 인과관계를 확인하였다. 현대 사회는 일인 가정이 많아지고 코로나로 인해 사회적 만남이 제한됨으로써 외로움에 취약한 환경에 처한 개인이 전례 없이 많다. 본 연구는 이러한 현 상황에 서 외로움 완화의 요인으로써 상황의 변화보다는 개인의 내적 심리적 측면에 주목하였다는 점에서 의의를 지닌다.

In order to improve the implementation of safety and health education at the site for industrial accident prevention activities, research was conducted to minimize inconvenience and increase utilization by redesigning and developing existing education methods. To date, occupational safety and health education has been conducted without considering the general work characteristics and functional facilities (mechanical, electrical, instrumentation, chemical) of workers (mechanical: turbine, valve, pump, hydraulic system, electrical: generator, breaker, motor, etc.). In particular, plant facilities were classified as mechanical and electrical facilities to improve the methodology for industrial safety and health education for plant maintenance workers. In addition, the “One Page Education Plan” was announced as a learning case because the spread of COVID-19 infectious diseases made it impossible to reduce or control the number of people in all groups and groups. The improvement of this training method will play a major role in improving the effectiveness of safety education in power plant workplaces.

권력과 지위는 사회계층을 구분하는 핵심 요소들로 사회적 상호작용에 강한 영향을 미친다. 이 둘은 사회적 영향 력의 기반이 된다는 공통점을 가지지만, 서로 다른 원천에 의해 발생한다는 차이점을 보인다(Fragale et al., 2011). 권력은 주로 능력이나 법적, 제도적 정당성에 근거하지만 지위는 타인의 자발적인 지지에 근거한다. 따라서 권력자 는 자기중심적으로 행위하지만, 지위를 가진 사람은 관계중심적으로 행동하는 경향이 있다(Hasty & Maner, 2020). 사람들 또한 이러한 차이를 인식하여 권력과 지위에 따른 사람들의 행동에 대해 고정관념 혹은 기대를 가진다 (Magee, 2009). 본 연구는 권력 혹은 지위의 중요한 사회적 영향인 사회적 배제 행위에 대한 판단이 행위자의 권력과 지위에 따라 어떻게 달라지는지를 검증했다. 이를 위해 행위자의 권력, 지위, 익명성을 조작한 사회적 배제 시나리오 를 구성하여 참가자들에게 행위자의 고통과 행위 공정성을 평정하도록 요청했다. 그 결과 참가자들은 권력과 지위에 따라 행위자의 공정성과 고통이 달라질 것이라고 응답했으며(실험 1), 이는 앞서 언급한 고정관념과 일치하는 패턴을 보였다. 특히 권력이 낮을 때와 지위가 높을 때 익명성에 따른 효과가 유의미하게 달라졌으며(실험 2A, 2B) 이는 권력보다는 지위가 타인의 자발적인 지지에 근거한다는 주장에 대한 경험적인 증거를 제공한다.

In korea, 500MW standard coal fired power plants were designed and operated for the initial base load, so facility stability was prioritized from facility problem to treatment, but now we needed to research for minimizing greehouse gas emissions at the operation of coal fired power plants. research on various facilities and technologies was actively conducted to reduce environment pollutants was drastically reduced, but research and attempts on coping measures in the event of a reduction facility problem were in sufficient. this study considered investigated ways to minimized pollutants by quickly responding to logic development and application of the load runback concept in case of serious problems with environmental pollutant reduction facilities such as NOx reduction selective catalytic reduction facilities, SOx reduction wet flue gas desulpherisation facilities, and TSP(Total Suspended Particles) collection low temperature electric precipitator.