• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.690-697
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• 2018

Criticality alarm systems (CASs) are mandatory in nuclear plants for prompt alarm in the event of any criticality incident. False criticality alarms are not desirable as they create a panic environment for radiation workers. The present article describes the design enhancement of the CAS at each stage and provides maximum availability, preventing false criticality alarms. The failure mode and effect analysis are carried out on each element of a CAS. Based on the analysis, additional hardware circuits are developed for early fault detection. Two different methods are developed, one method for channel loop functionality test and another method for dose alarm test using electronic transient pulse. The design enhancement made for the external systems that are integrated with a CAS includes the power supply, criticality evacuation hooter circuit, radiation data acquisition system along with selection of different soft alarm set points, and centralized electronic test facility. The CAS incorporating all improvements are assembled, installed, tested, and validated along with rigorous surveillance procedures in a nuclear plant for a period of 18,000 h.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.456-462
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• 2014

In this paper, we develop a facility management system which provides fault effect and replacement alarm function of each component for supporting effective maintenance of facility. To do this, we use weighting method to each component, calculate importance of each component, and make them to hierarchy structure using bill of materials of facility. Also, we draw fault cause and fault effect of components based on failure modes effects and criticality analysis, and define criteria of severity, occurrence and detection to get risk priority number. To apply these concepts, we develop and test the facility management system to verify its practicality. In the future, we expect the developed system to apply many domains such as maintenance of ship and offshore plant.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.135-143
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• 2011

Currently network management systems(NMS) just give useful information about the criticality of the alarms and the process of the fault analysis is mainly dependent on the experts who have many years experiences in the field. Due to these reasons it takes very much time and manpower cost to localize the real root of the fault from the alarm information. Therefore, to solve these problems in this research we analyze the probability of the fault for each alarm and provide how to give the problem solving procedure with confidence level and give idea to build a system to realize the problem solving procedure. In addition, we give a case study to show how to use the proposed ideas.