• Journal of the Korean Society of Safety
• /
• v.35 no.4
• /
• pp.84-91
• /
• 2020

The Korean nuclear industry developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code and this code adpots two-phase flows, two-fluid, three-field models which are comprised of gas, continuous liquid and droplet fields and has a capability to simulate three-dimensional model. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for accident management plan of 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 work for separate and integral effect experiments is required. In this reason, the goal of this work is to verify calculation capability of SPACE code for multiple failure accident. For this purpose, it was selected the experiment which was conducted to simulate a Multiple Steam Generator Tube Rupture(MSGTR) accident with Passive Auxiliary Feedwater System(PAFS) operation by Korea Atomic Energy Research Institute (KAERI) and focused that the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The MSGR accident has a unique feature of the penetration of the barrier between the Reactor Coolant System (RCS) and the secondary system resulting from multiple failure of steam generator U-tubes. The PAFS is one of the advanced safety features with passive cooling system to replace a conventional active auxiliary feedwater system. This system is passively capable of condensing steam generated in steam generator and feeding the condensed water to the steam generator by gravity. As the results of overall system transient response using SPACE code showed similar trends with the experimental results such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it could be concluded that the SPACE code has sufficient capability to simulate a MSGTR accident.

• Korean Institute of Interior Design Journal
• /
• v.23 no.4
• /
• pp.257-266
• /
• 2014

This study has been performed to come up with any rational way for responding to the functions of fire-fighting spaces newly required by the changing social paradigms and to seek for the approach to designing fire-fighting spaces by taking into account the psychological and behavioral factors of fire-fighters who are exposed stress of operations. In particular, it is to satisfy any physical and functional requirements as special working-spaces and to reflect the psychological and behavioral approach to the workers who are forced to be at standby for a long time, which is the characteristic of their operation, to designing. Accordingly, for fundamental appreciation of whether or not such space programs as space organization needed for operational function are being practiced actively, the fire-fighting headquarters of Incheon City has been selected for the research. First, in the process of assessing the trend of organizing the space at safety centers for the recent 20 years, those built more than 20 years ago were left out from the space selection for the research. Second, those with less than 20 operators also were excluded. Third, among those completed in the same year, only one was selected, which was to avoid overlapping, with the consideration its regional representative nature for applying the safety centers in the jurisdiction of the headquarters equally. The study was performed through the visits to and the actual inspections by surveys at the selected 119 Safety Centers as well as the reviews of literature based on case studies. And for the assessment of significance, surveys and analysis of reliability and factors were carried out. The actual users of Safety Centers were picked as objects for the assessment of significance of space factors at 119 Safety Centers, which revealed that there are five types of dimensions for factor-analyzing standard with which users estimate any significance, which are "Area of Mobilization Preparation and Return" "Area of Standby" "Area of Working Activities" "Area of Employ Welfare" and "Area of Support".

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.2
• /
• pp.121-128
• /
• 2020

The Marine Safety Culture Index (MSCI) was developed in the year 2018 for objectively assessing the public safety culture levels and for incorporating it as data to spread knowledge regarding the marine safety culture. The method for calculating the safety culture index should include issues that may affect the safety culture and should consist of appropriate attributes for estimating the current status. In addition, continuous verification and supplementation are required for addressing social and economic changes. In this study, to determine whether the questionnaire designed by marine experts reflects the people's interests and needs, we analyzed 915 marine safety proposals. Text mining was employed for analyzing the unstructured data of the marine safety proposals, and network analysis and topic modeling were subsequently performed. Analysis of the marine safety proposals was centered on attributes such as education, public relations, safety rules, awareness, skilled workers, and systems. Eighteen questions were modified and supplemented for reflecting the marine safety proposals, and reliability of the revised questions was analyzed. Furthermore, compared to the previous year, the questionnaire's internal consistency was improved upon and was rated at a high value of 0.895. It is expected that by employing the derived marine safety culture index and incorporating the improved questionnaire that reflects the requirements of marine experts and the people, the improved questionnaire will contribute to the establishment of policies for spreading knowledge regarding the marine safety culture.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.5
• /
• pp.413-419
• /
• 2008

Deterministic design optimization (DO) does not explicitly deal with a variety of factors from inherent randomness and uncertainties. Reliability based design optimization(RBDO) is necessary to use in engineering systems in order to guarantee quality and performance of product. In this paper, design variables are considered as random variables. Standard deviation according to change of design variables have changed as much as coefficient of variation. And, if the standard deviation is error of manufacturing, standard deviation-mean relation is concave form. We obtain reliability index using advanced first order second moment method(AFOSM). This paper is examined by solving two examples and the results are compares with DO, RBDO and suggested RBDO.

• Journal of Digital Convergence
• /
• v.16 no.9
• /
• pp.207-217
• /
• 2018

The purpose of this study was to develop a patient safety nursing activities scale for clinical nurses and to verify validity and reliability it. A preliminary scale was developed through various processes and pilot study. Data were collected from 900 nurses at 28 hospitals selected by proportionate stratified sampling with 331 general hospitals nationwide. The final scale was a 4-point scale, consisting of 72 items in 10 domains. The construct validity was found to be appropriate by exploratory factor analysis and 70.3% of the variance in the total scale and over .74 of factor loading. There was a significant correlation between scale and patient safety culture (r=.52, p<.001) and Cronbach's ${\alpha}$ was .99. This scale developed to measure patient safety nursing activities of clinical nurses was found to be reliable and valid and will be a useful tool in practical field.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.5
• /
• pp.199-204
• /
• 2006

To develop a safety-critical network in nuclear power plants that puts more stringent requirements than the competitive commercial ones do, we establish four design criteria - deterministic communication, explicit separation/isolation structure, reliability, verification & validation. According to those design criteria, the fundamental design elements are chosen as follows - a star topology, point-to-point physical link, connection-oriented link control and fixed allocation access control. After analyzing the design elements, we also build a communication architecture with TDM (Time Division Multiplexing) bus switching scheme. Finally, We develop a DDCNet (Deterministic Data Communication Network) based on the established architecture. The DDCNet is composed of 64 nodes and guarantees the transmission bandwidth of 10Mbps and the delay of 10 msec for each node. It turns out that the DDCNet satisfies the aforementioned design criteria and can be adequately utilized for our purpose.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1389-1394
• /
• 2010

This paper describes the evaluation of structural integrity and dynamic characteristic of inertial load test equipments for performance test of railway vehicle propulsion control system. The propulsion control system of railway vehicle has to be confirmed of safety and reliability prior to it's application. Therefore, inertial load test equipments were designed through theoretical equation for performance test of propulsion control system. The structural analysis of inertial load test equipments was conducted using Ansys v11.0 and it's dynamic characteristic was evaluated the designed using Adams. The results showed that the structural integrity of inertial load test equipment was satisfied with a safety factor of 10.2. Also, the structural stability was proved by maximum dynamic displacement of 0.82mm.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.8
• /
• pp.849-857
• /
• 2009

To guarantee the safety and reliability of obsolete thermal power plants, on site routine patrol in their facilities has been done by human workers. Due to their poor working environments, however, a patrol robot system has been gradually required instead of the human workers from the viewpoint of the workers' safety and work efficiency. For this purpose, this paper presents a patrol robot, controllers, and its control scheme. Especially, this robot system uses a line tracing algorithm, which uses a vision camera instead of IR sensors, and an RFID system for its patrol operation. We confirmed its effectiveness through experiments.

• Journal of the Korea Safety Management & Science
• /
• v.6 no.3
• /
• pp.121-130
• /
• 2004

This Study will introduce the concept of CTP(Capable-to-Promise) Algorithm, CTP process, and the modeling of algorithm. This research is based on the environment of using Job-Shop method. CTP algorithm model use LPST(Latest Possible Start Time) and EPST(Earliest Possible Start Time) method especially. It is important part of executing CTP system. The CTP modeling and implementing develops to system which is able to implement in the various business environment through additional and continuous research.

• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.123-134
• /
• 1999

There are several models for process quality assurance by quality system (ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal or lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These paramaters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.