• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4266-4273
• /
• 2023

In a severe reactor accident, a crust will form on the surface of the molten material during the core melting process. The crust will have a contact melting with the internal components of the reactor. In this paper, the contact melting process of the molten material on the austenitic stainless steel plate bundles is studied. The contact melting model of parabolic molten material on the plate bundles is proposed, and the rule and main effect factors of the contact melting are analyzed. The results show that the melting velocity is proportional to the slope of the paraboloid, the heat flux and the distance between two plates D. The influence of melt gravity and the plate width on melting velocity is negligible. The thickness of the molten liquid film is proportional to the heat flux and plate width, and it is inversely proportional to the gravity. With the increase of D, the liquid film thickness decreases at first and then increases gradually. The liquid film thickness has a minimum against D. When the width of the plate is small, the width of the plate is the main factor affecting the thickness of the liquid film. The parameters are coupled with each other. In a severe reactor accident, the wider internal components of reactor, which can increase the thickness of the melting liquid film and reduce the net input heat flux from the molten material to the components, are the effective measures to delay the melting process.

• Journal of the Ergonomics Society of Korea
• /
• v.35 no.3
• /
• pp.135-142
• /
• 2016

Objective: Objective of this study is to provide characteristics of injury frequency and severity by driving condition in large truck-related traffic collisions. Background: Traffic accidents involving large trucks draw a lot of attention in accident prevention and management policies since they bring about severe human and financial damages. Method: In order to identify the major risk factors of accidents by driving condition, 255 recognized traffic accidents by large truck drivers were analyzed in terms of time of the day, road type, and shape of the road. Results: The driving conditions in the results are represented by the following form of combination, "Road Type (Non-expressway or Express) - Shape of Roads (Straight, Curved, Downhill, or Intersection) - Time of Accidents (Day or Night)". In the analysis of injury frequency, Non-expressway-Straight-Day condition was the most frequent one. Meanwhile, Expressway-Curved-Day, Non-expressway-Curved-Night and Non-expressway-Intersection-Night were evaluated as high level in view of injury severity. Also, Expressway-Straight-Night is the driving condition that is the highest in risk among the conditions that have to be managed as grade "High". Non-expressway-Straight-Night, Non-expressway-Downhill-Day, and Non-expressway-Curved-Day are also categorized as grade "High". Conclusion and Application: Safety managers in the fields require basic information on accident prevention that can be easily understood. The research findings will serve as a practical guideline for establishing preventive measures for traffic accidents.

• Journal of Auto-vehicle Safety Association
• /
• v.13 no.3
• /
• pp.78-85
• /
• 2021

Recently a traffic accident of heavy duty vehicles under the mandatory installation of ADAS (Advanced Driver Assistance System) is often reported in the media. Heavy duty vehicle accidents are normally occurring a high number of passenger's injury. According to report of Insurance Institute for Highway Safety, FCW (Forward Collision Warning) and AEB (Automatic Emergency Braking) were associated with a statistically significant 12% reduction in the rate of police-reportable crashes per vehicle miles traveled, and a significant 41% reduction in the rear-end crash rate of large trucks. Also many countries around the world, including Korea, are studying the effects of ADAS installation on accident reduction. Traffic accident statistics of passenger vehicle for business purpose in TMACS (Traffic safety information Management Complex System in Korea) tends to remarkably reduce the number of deaths due to the accident (2017(211), 2018(170), 2019(139)), but the number of traffic accidents (2017(8,939), 2018(9,181), 2019(10,095)) increases. In this paper, it is introduced a traffic accident case that could lead to high injury traffic accidents by being equipped with AEB in a bus. AEB reduces accidents and damage in general but malfunction of AEB could occur severe accident. Therefore, proper education is required to use AEB system, simply instead of focusing on developing and installing AEB to prevent traffic accidents. Traffic accident of AEB equipped vehicle may arise a new dispute between a driver's fault and vehicle defect. It is highly recommended to regulate an advanced event data recorder system.

• Journal of the Korea Institute of Construction Safety
• /
• v.5 no.1
• /
• pp.17-24
• /
• 2023

The purpose of this study is to clearly recognize critical issues and to suggest relevant solutions for the issues since too many deaths and injuries due to industrial accidents has been going on for a long time, also the deaths of workers is a problem that affects not only one person's death but also many people connected with it and society as a whole. And the need for a strict Serious Accidents Punishment Act is sympathetic. However, the current Severe Accident Punishment Act is not welcomed by both labor and management due to its ambiguity, and it is suggested that the punishment and legislative content of the management manager who violated the duty to ensure safety and health is abstract and the level of punishment is excessive. In addition, due to the ambiguous part of the management manager's interpretation and serious industrial accidents, most companies appoint large law firms to receive legal interpretation and advice, so only law firms are getting full, and the cost that companies invest to protect the CEO is actually a safety accident. It is suggested that the current enforcement ordinance, which has ambiguity, needs to be revised because it must be entered into as a preventive cost.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.6
• /
• pp.163-170
• /
• 2023

With the introduction of the law regarding severe penalties for major accidents, employers, management executives, and corporations have significantly increased the number of safety managers and invested extensively in acquiring ISO certifications to prevent accidents in industrial sites. Moreover, the implementation of the Smart Safety Management System (SSMS) has facilitated the management of personnel and safety equipment. While IoT-based management systems have been applied to safety gear such as helmets, safety harnesses, and protective clothing, the responsibility for safety shoes still primarily lies with on-site managers and individuals, leaving a vulnerability to accidents. In this study, we aim to implement a Raspberry Pi-based sensor device to proactively detect workers' safety shoe usage upon entering the site. The goal is to confirm the usage of safety shoes and prevent accidents that may occur due to non-compliance with safety shoes regulations.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.5
• /
• pp.605-611
• /
• 2023

Accidents at construction sites have a very high rate of fatalities due to the nature of being prone to severe injury patients. In order to reduce the mortality rate of severely injury patients, quick response is required, and some systems that detect accidents using AI technology and cameras have been devised to respond quickly to accidents. However, since existing accident detection systems use only a single camera, there are blind spots, Thus, they cannot detect all accidents at a construction site. Therefore, in this paper, we present the system that minimizes the detection blind spot by using multiple cameras. Our implemented system extracts feature points from the images of multiple cameras with the YOLO-pose library, and inputs the extracted feature points to a Long Short Term Memory-based recurrent neural network in order to detect accidents. In our experimental result, we confirme that the proposed system shows high accuracy while minimizing detection blind spots by using multiple cameras.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.50 no.4
• /
• pp.614-622
• /
• 2014

The aim of this study is to research attributes of fishermen's occupational accidents for investigating the measure of risk control on situational condition in the Korean offshore and coastal fishing vessel. Using data of fishermen's occupational accidents are from National federation of fisheries cooperatives for 2013. The results were as belows; Occupational accident occurrence rate was 29.5‰, slips & trips and struck by object and contact with gear were shown severe occurrence pattern. Occupational accident occurrence rate of offshore fisheries was 130.2‰, coastal was 16.9‰, specially the risk rates were severely high in several type of danish seine, stow net and offshore trap. Death rate by accidents was 10.6‰ and by fall into the water in occurrence pattern was 5.5‰.

• Journal of the Korea Institute of Building Construction
• /
• v.8 no.3
• /
• pp.127-133
• /
• 2008

Safety accident resulting from construction projects getting larger and complex day by day has occurred more often than ever. Particularly, the accident caused by construction equipment, among others, has been on the rise. To prevent such accidents, it's necessary to come up with the measures for reducing the accident. In this study, the cause of safety accidents was analyzed, reviewing the cases of safety accident maintained by Korea Occupational Safety & Health Agency, and the measures for reducing the accident was suggested with computerized safety checklist. The scope of study was limited to excavator, and the result is summarized as below. 1) Investigation was conducted to identify the cases of accident by excavator with the primary causes. 2) Reduction measures were suggested by category of cause of excavator-caused accident. 3) Checklist to prevent the safety accident, which was based on primary causes, was suggested. 4) The measures to stir up safety consciousness and monitor the safety were suggested, making use of computerized system. This study is expected to lay the foundation for further study in future as well as make a great commitment to reducing the safety accident.

• Nuclear Engineering and Technology
• /
• v.50 no.5
• /
• pp.673-682
• /
• 2018

One of the most widely used methods to estimate core damage during a nuclear power plant accident is containment radiation measurement. The evolution of severe accidents is extremely complex, leading to uncertainty in the containment dose rate (CDR). Therefore, it is difficult to accurately determine core damage. This study proposes to conduct uncertainty analysis of CDR for core damage assessment. First, based on source term estimation, the Monte Carlo (MC) and point-kernel integration methods were used to estimate the probability density function of the CDR under different extents of core damage in accident scenarios with late containment failure. Second, the results were verified by comparing the results of both methods. The point-kernel integration method results were more dispersed than the MC results, and the MC method was used for both quantitative and qualitative analyses. Quantitative analysis indicated a linear relationship, rather than the expected proportional relationship, between the CDR and core damage fraction. The CDR distribution obeyed a logarithmic normal distribution in accidents with a small break in containment, but not in accidents with a large break in containment. A possible application of our analysis is a real-time core damage estimation program based on the CDR.

• The Journal of Korea Robotics Society
• /
• v.16 no.3
• /
• pp.199-206
• /
• 2021

The robot is an effective means to perform repetitive tasks quickly and accurately. It could be more effective in dangerous environments where human is difficult to access. The construction site is a dangerous environment with a high possibility of industrial accidents where heavy work is frequently carried out at a high place. In particular, an accident in the construction site is highly likely to lead to a severe disaster. Of course, various technologies are being developed to monitor the safety of workers in construction sites and prevent accidents, but there is a limit to eliminate the risk of accidents. Therefore, it is necessary to make efforts to replace workers exposed to dangerous environments with equipment or robots that could be controlled remotely in a more active way. In this study, Remote Precise Installation System was proposed to replace the workers exposed to the risk of accident at a high place during the bridge construction. Also, the conceptual design and analytical reviews of this system were carried out. Suppose Remote Precise Installation System is developed according to the derived concept and the target performance. In that case, this system is expected to be applied as a technology that can effectively replace the workers at the bridge construction site.