• Nuclear Engineering and Technology
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• v.19 no.1
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• pp.10-21
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• 1987

Uncertainty analysis of the FLB accident is performed for KNU-1 using the response surface methodology and Monte Carlo simulation. The FLB analyses using the RELAP4/Mod6 were performed a number of times to generate the data base for the uncertainty analysis, along with the EM calculation for comparison purpose. Two kinds of input sets are utilized for response surface method to investigate and compare the effects of the uncertainty of input variables on the RCS peak pressure following a FLB. The first set is composed of six major plant operational parameters and the second set is composed of five major modelling parameters. It is found through the analysis of results that the uncertainties of modelling parameters have more influence on the RCS peak pressure than the uncertainties of plant operational parameters and that the extra margin of 9% of peak pressure is gained. And one of the assumptions of EM calculation, which is usually accepted as conservative is found to be erroneous, that is, the initial core inlet temperature is found to act negatively on the RCS pressure following a FLB.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.101-109
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• 2012

It is commonly recognized that railway is one of the representative transportation and it offers public service based on strategies for being rapid, automation, safety. Since the opening of high speed railway, 3-hundred-million people have used it and acknowledged its efficiency. However, derailed accident at Kwangmyeong station in February, 2011, frequent malfunction of KTX-Sancheon, and accidents by engineer's careless fault damaged on credibility of safety, Especially, spreaded accidents through social networking service by cell phones amplified anxiety of public, being criticized by the press. This study analyzed statistics of past accident and cases of passing-by accident, and surveyed 152 KTX captain engineers about their recognition of the accident by careless fault and experiences of possibility of occurrence for preventing engineer's careless fault and restoring trust According to the analysis, engineers worry about responsibility and disadvantages related to the accidents for the most, and they are nervous about malfunction for the second most. This study presents prevention methods regarding the result. First, it is required to improve mental stability and concentration on their work, secondly, advanced ability to cope with malfunction or error through repetitive education and training are required to increase confidence, and for the last, improvement of operational supporting system such as ATP, GPS to prevent errors by human factors. Improvement of the system is expected to lead engineers to prevent careless fault and regain the reputation of railway.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.136-147
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• 2022

The purpose of this study is to analyze four cases of firefighter burns in various fire scenes and to find prevention measures to decrease firefighter injuries. Among the analysis reports prepared by the National Fire Research Institute of Korea from 2016 to 2020, four burn-related accidents are summarized and the main causes are conveyed. The four accidents include second-degree burns from using extinguishers during containment of fires; nine firefighters burned due to re-ignition in the LPG car repair shop; two firefighters injured with third-degree burns from using fire extinguishers during life-saving events in residential housing; and injuries from the radiant heat of the tank BLEVE near the factory fire. These cases are comprehensively investigated in their respective scenes and analyzed based on the fire site investigation reports from the fire department and related theoretical explanations of risk for each accident scene. In the third case study, some experimental research is conducted to evaluate the risk involved with the use of safety gloves. This is evaluated by reviewing Fire Tactics and Standard Operational Procedures (SOP) to determine improvements and recommendations for an efficient firefighting response. Results show that the main causes of burn accidents are the insufficient use of personal protective equipment (PPE), such as safety gloves, and the failure to follow firefighting tactics or SOPs. Through the accident investigation and assessment, it is concluded that to reduce the frequency of burn accidents, the performance of firefighting equipment, SOPs, protection tactics, and safety policy systems require improvement.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.160-167
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• 2014

To determine a proper ASIL for each hazardous event with a proper safety goal, the right classes should first be determined for the three properties of the hazardous event; (i) severity of harm from the resultant accident, (ii) exposure to the relevant operational situation, and (iii) controllability to avoid the induced risks. ASIL can be clearly determined with right classes of these three properties. But no specific methodologies or processes for their classification can be found in ISO 26262, except only a rough guideline with a simplified set of illustrative tables. In this paper, we try to present a systematic model for classifying the three properties of the hazardous event and suggest a refined procedure of ASIL determination. The proposed model provides a specific method to get a more objective ASIL compared with that in the standard. Scrutinizing the current methodology, we develop a refined method and also provide an illustrative example.

• Korea Trade Review
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• v.46 no.4
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• pp.149-166
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• 2021

This paper aims to reduce the frequency of dangerous goods storage accidents in China. Advocating the managers of warehousing and logistics enterprises to pay attention to the operation process of dangerous goods warehousing business. Improving the safe storage and management capabilities of dangerous goods warehouses. This article first collects official data on dangerous goods storage accidents in China and conducts a general statistical analysis of the accidents. Based on the results of accident statistics and related literature research on dangerous goods storage management, establish a dangerous goods storage safety management factor system, use the analytic hierarchy process, establish a factor importance questionnaire and implement data collection. Through statistics, this paper finds that the storage accidents of dangerous goods in China in the past ten years mainly occurred in the inbound phase of dangerous goods and the storage phase of dangerous goods warehouses. Through the results of the analytic hierarchy process, it is found that the professionalism of the dangerous goods storage practitioners, the compliance of the practitioners with safety regulations, and the awareness of operational safety are the most important.

• Journal of Fisheries and Marine Sciences Education
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• v.14 no.2
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• pp.149-160
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• 2002

I have been analyzed the marine accidents during 10years(1992~2001) based on the maritime inquire court decision, the results were as follows: 1. The rate of accident occuring were showed fishing boat(69.9%), freighter(12.3%), tanker(4.3%), tug boat(3.8%), passenger boat(2.1%) by the usage. 2. The marine accident had been showed operational fault(67.3%), mishandling of engine equipment(21.7%), meteorological condition, etc(11%) by the reason, most accidents had been occured by the operator fault and rack of experience. 3. The marine accidents had been showed damage of hull and engine(27.5%), collision(24%), foundering(11.3%), fire(3.9%), agrounding(10%), by the kind of accidents. 4. The accidents had been occured (74.6%) at the coastal sea, harbour and (25.4%) at the open sea by the sectors. The accidents of the vessel less than 500ton were much increased (54.3%) also, The accidents were much occured at the time between 0400~0800 hours by the time.

• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.330-340
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• 2016

The main objective of study was to analyze the effectiveness of transit mall. To this end, this study compared operational status of transit malls in operation (Daegu, Seoul and Busan). For the city of Busan where the latest transit mall became operational in 2015, a discriminant model was proposed to determine user satisfaction/dissatisfaction. The outcomes of comparative study showed that each city has different operational focus - Seoul has focus on traffic demand management, Busan has focus on walking environment, and Daegu has focus on accessibility to public transportation. Also, the discriminant model indicated that market sentiment, convenience of bus service, traffic accident risk, number of pedestrian, market user number have effects on user satisfaction. These results implied that, to improve user satisfaction, measures for market revitalization such as opening events and forming consultative groups need to be prepared and traffic conditions should also be improved through expansion of curfew time, linkage with subway station.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.753-758
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• 2005

A flux-lock type superconducting fault current limiter(SFCL) consists of two coils, which are wound in parallel each other through an iron core, and a high-$T_c$ Superconducting(HTSC) thin film connected in series with coil 2. If the current of the HTSC thin film exceeds its critical current by the fault accident, the resistance of the HTSC thin film generated, and thereby the fault current can be limited by the impedance of the fluk-lock type SFCL. In this paper, we investigated the dependence of both the fault current limiting characteristics and the current distribution between two coils on the operational current of the flux-lock type SFCL through the equivalent circuit analyses and short circuit tests. From the comparison of both the results, the experimental results well agreed with the analyses for equivalent circuit.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.152-161
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• 2022

We analyzed mitigation strategies for steam generator tube rupture (SGTR) accidents using MARS code under both full-power and low-power and shutdown (LPSD) conditions. In general, there are two approaches to mitigating SGTR accidents: supplementing the reactor coolant inventory using safety injection systems and depressurizing the reactor coolant system (RCS) by cooling it down using the intact steam generator. These mitigation strategies were compared from the viewpoint of break flow from the ruptured steam generator tube, the core integrity, and the possibility of the main steam safety valves opening, which is associated with the potential release of radiation. The "cooldown strategy" is recommended for break flow control, whereas the "RCS make-up strategy" is better for RCS inventory control. Under full power, neither mitigation strategy made a significant difference except for on the break flow while, in LPSD modes, the RCS cooldown strategy resulted in lower break and discharge flows, and thus less radiation release. As a result, using the cooldown strategy for an SGTR under LPSD conditions is recommended. These results can be used as a fundamental guide for mitigation strategies for SGTR accidents according to the operational mode.

• Nuclear Engineering and Technology
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• v.34 no.2
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• pp.176-185
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• 2002

A 4-bundle shift refuelling method of CANDU6 F/H (Fuel Handling) System is analyzed to assess the operational flexibility and capacity of F/H system. The current 8-bundle shift refuelling scheme requires to refuel eight fuel bundles from a single fuel channel, and to refuel 14 fuel channels in a week on average assuming that the reactor is in a steady state. The analysis showed that the 4-bundle shift refuelling method increases F/M (Fuelling Machine) duty cycle and operator load. However, the fuellin’g method change from the 8- to 4-bundle shift refuelling ill not require additional team of operators. A marginal increase in the maintenance cost may be resulted in by the change of fuelling method and the increase of fatigue usage factors requires some components to be replaced during the FM lifetime.