• Journal of Energy Engineering
• /
• v.25 no.1
• /
• pp.145-152
• /
• 2016

Recently, we can find news about toxic and combustible gas accident. So, we have to develop gas detector that can measure gas at dangerous area for preventing gas accidents. In this paper, we calculate a approximation function from sensor's output using the linear regressiong. And we develop software algorithm using Neville's algorithm for measuring gas concentration. Finally, we compare our algorithm with combustible gas detectors that are already developed, by using standard gas samples manufactured Korea Gas Safety. As a result of this experiment, we confirm that performance of our algorithm is more improved than performance of already developed combustible gas detectors. In the future, we'll research how to improve reliability from using count, temperature and humidity. And we'll design hardware applied explosion proof for safety.

• Journal of the Korean Society of Safety
• /
• v.37 no.5
• /
• pp.80-88
• /
• 2022

The Korean nuclear industry had developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code, which adopts a two-fluid, three-field model that is comprised of gas, continuous liquid and droplet fields and has the capability to simulate three-dimensional models. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for the accident management plan of a nuclear power plant was determined based on the lessons learned from the Fukushima accident. Generally, to improve the reliability of the calculation results of a safety analysis code, verification is required for the separate and integral effect experiments. Therefore, the goal of this work is to verify the calculation capability of the SPACE code for multiple failure accidents. For this purpose, an experiment was conducted to simulate a Control Element Drive Mechanism (CEDM) break with a safety injection failure using the ATLAS test facility, which is operated by Korea Atomic Energy Research Institute (KAERI). This experiment focused on the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The results of the overall system transient response using the SPACE code showed similar trends with the experimental results for parameters such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it can be concluded that the SPACE code has sufficient capability to simulate a CEDM break with a safety injection failure accident.

• Journal of the Korean Society of Safety
• /
• v.21 no.3 s.75
• /
• pp.137-142
• /
• 2006

Quantification of error possibility, in an HRA process, should be performed so that the result of the qualitative analysis can be utilized in other areas in conjunction with overall safety estimation results. And also, the quantification is an essential process to analyze the error possibility in detail and to obtain countermeasures for the errors through screening procedures. In previous studies for the quantification of error possibility, nominal values were assigned by the experts' judgements and utilized as corresponding probabilities. The values assigned by experts' experiences and judgements, however, require verifications on their reliability. In this study, the validity of new error possibility values in new MCR design was verified by using the Onisawa's model which utilizes fuzzy linguistic values to estimate human error probabilities. With the model of error probabilities are represented as analyst's estimations and natural language expression instead of numerical values. As results, the experts' estimation values about error probabilities are well agreed to the existing error probability estimation model. Thus, it was concluded that the occurrence probabilities of errors derived from the human error analysis process can be assessed by nominal values suggested in the previous studies. It is also expected that our analysis method can supplement the conventional HRA method because the nominal values are based on the consideration of various influencing factors such as PSFs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.4
• /
• pp.123-128
• /
• 2010

In this paper, in order to reduce the electric disaster damage which is caused by with electric equipment of traditional markets, we developed cabinet panel and the electric safety monitoring system which is able to monitor the electrical equipments condition(over current, leakage, arc, WH, electrical fire factor etc.) at traditional markets. We constructed Test-bed for testing reliability of electric safety monitoring system and the actual condition investigation about electrical equipment of traditional market. This paper will be used with the data for an actual demonstration project after reinforcing problems which are occurred to operation of traditional market actual loads.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.161-164
• /
• 2008

It is played an important part in dam safety that KWATER is taken the responsibility of design, construction and maintenance about dam. It is considered that safety inspection of accumulated technology and knowledge of new evaluation method have developed. Thus this study is that instrumentation data is analyzed continually and dam's safety is evaluated about behavior property, in Chungju concrete dam. New evaluation method is that instrumentation data is analyzed reliability. It is suggested that suitability of management period and maintenance of instrument in dams.

• Journal of the Korean Society of Systems Engineering
• /
• v.18 no.1
• /
• pp.46-57
• /
• 2022

In this paper, we proposed the DFMEA Implementation Method for safety design of Weapon System. First, we presented the process for DFMEA. And then, the case analysis of OOO missile was performed in accordance with the process presented. After defining the system requirements of OOO missile, failure definition scoring criteria was set. In order to clarify the definition of failure, the failure was classified into safety, reliability, maintainability and others. After performing the function analysis, the relationship matrix analysis was performed to identify the failure mode according to the function without omission. After clarifying the failure classification, mode of failure, cause of failure and effect were analyzed to calculate the severity, occurrence and detection values. After the action priority was judged, the recommended action according to the failure classification was identified for the determined action priority. The results of this study can be used as a relevant basis for the design reflection and resource re-allocation of stakeholders.

• Journal of the Korean Society of Safety
• /
• v.38 no.6
• /
• pp.9-15
• /
• 2023

Hydrogen is gaining attention as a sustainable and renewable energy source, potentially replacing fossil fuels. Its high diffusivity, wide flammable range, and low ignition energy make it prone to ignition even with minimal friction, potentially leading to fire and explosion risks. Workplaces manage ignition risks by classifying areas with explosive atmospheres. However, the effective installation of a blast wall can significantly limit the spread of hydrogen, thereby enhancing workplace safety. To optimize the wall installation of this barrier, we employed the response surface methodology (RSM), considering variables such as wall distance, height, and width. We performed 17 simulations using the Box-Behnken design, conducted using FLACS software. This process yielded two objective functions: explosion likelihood near the barrier and explosion overpressure affecting the blast wall. We successfully achieved the optimal solution using multi-objective optimization for these two functions. We validated the optimal solution through verification simulations to ensure reliability, maintaining a margin of error of 5%. We anticipated that this method would efficiently determine the most effective installation of a blast wall while enhancing workplace safety.

• Journal of Applied Reliability
• /
• v.15 no.4
• /
• pp.276-281
• /
• 2015

Purpose : The purpose of this study is to propose that domestic rail must the work to be done in the RCM system and railway operators are to present a direction to establish the efficient and systematic system based on this. Methods : In recent years, domestic railway accidents has decreased year rapidly every year. In particular, suicidal ideation was greater than 50% of the accidents is showing a larger decrease in the influence of the screen-door construction. However, the train delay has been maintained without major changes since 2010. The most important cause of the delay operation is a vehicle breakdown. This fact demonstrates that effective maintenance of the most important activities in the railway accident prevention activities. So we have to build a RCM system in which the characteristics of the domestic railway accident. Conclusion : We proposed what is necessary functionality and the function requires a railway operators in RCM railway systeml.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.4
• /
• pp.140-145
• /
• 2015

In the present study, the structural safety of the bolt portion and collet tool structure of the pipe-fitting tool is analyzed by using the finite element technique. Two forces as piston forces with the magnitude of 187.5 Tons are applied to the inner and outer portions of the collet tool, respectively. A structural load of 750 Tons is applied to the bolt portion. In the analysis results, it is found that the structure becomes safe under the current loading conditions. The reliability rating of the pipe is calculated in this study. The material properties of the actual material are evaluated by using mechanical testing. Therefore, the material properties are used to carry out static structural and optimization analysis.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2011.04a
• /
• pp.77-79
• /
• 2011

본 논 연구에서는 가전제품 중에서 야간 절전 버튼의 작동 불량 원인을 규명하여 제품의 성능 및 신뢰성 향상을 위한 객관적 근거를 제시하였다. 시판된 제품을 수거하여 불량품 검사(전기적 특성 및 decap)를 실시한 결과 절전 버튼 IC pin No.2의 단락(short)에 의한 오작동 요소를 밝힐 수 있었다. 동일한 사양의 재현실험에서 EOS(전기적 과도전압에 의한 스트레스)보다 정전기 방전에 스트레스에 의해서 소손되는 특성을 나타내는 것을 확인할 수 있었다. 오작동 요소로 확인된 IC pin 2번에 바리스터(Varistor)를 부착하고 11kV를 인가하여 시험한 결과 오작동 요소를 제거할 수 있었다.