• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.133.6-133
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• 2001

Reactor vessel is one of the most important equipment of Nuclear Power Plant (NPP) with regard to the nuclear safety. Thus reactor vessel must be examined periodically by certified experts. Currently, ultra-sonic(UT) non-destructive inspection is executed on reactor vessel. Two different techniques are used in this inspection. One is using the movable manipulator fixed with the support-guide placed on the vessel, and the other is using mobile robot moving in the vessel. Movable manipulator machine is very heavy, hard to handle, and very expensive. Mobile robot equipment is small and convenient but has a weak point on positional precision. To solve these problems we developed a reactor inspection system based on laser-driven mobile robot. This paper describes the main concept and structure of integrated inspection units and the feature of implemented units.

• Proceedings of the Korean Reliability Society Conference
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• 2002.06a
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• pp.217-224
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• 2002

The performance demonstration round robin test was conducted to quantify the capability of ultrasonic inspection for in-service and to address some aspects of reliability for nondestructive evaluation. The fifteen inspection teams who employed procedures that met or exceeded ASME Sec. XI code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection. With data from PD-RR test, the performance of ultrasonic nondestructive inspection could be assessed using probability of length and depth sizing of cracks.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.4
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• pp.380-385
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• 2010

The integrity of components and piping of operating nuclear power plants has been identified by in-service inspection(ISI) requirements and activities commensurate with standards and codes such as KEPIC MI or ASME Code Section XI. However, the other various degradation mechanisms not considered during design stage of nuclear power plants have been checked by enhanced ISI. The requirements of enhanced ISI have been voluntarily developed by the industry itself or strickly issued by regulatory body. Even though the requirements were developed by the industry, they should be reviewed by regulatory body for their application in nuclear power plants. The enhanced ISI activities and requirements of non-destructive examination(NDE) which reflect the degradation issues in nuclear power industry will be primarily discussed in this paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.725-730
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• 2017

The use of general IT resources in the Instrumentation and Control system(I&C) for the safety of Nuclear Power Plants(NPPs) is increasing. As a result, potential security vulnerabilities of existing IT resources may cause cyber attack to NPPs, which may cause serious consequences not only to shutdown of NPPs but also to national disasters. In order to respond to this, domestic nuclear regulatory agencies are developing guidelines for regulating nuclear cyber security regulations and expanding the range of regulatory targets. However, it is necessary to take measures to cope with not only general security problems of NPPs but also attacks specific to NPPs. In this paper, we select 42 items related to the vulnerability inspection in the contents defined in R.G.5.71 and classify it into 5 types. If the vulnerability inspection tool is developed based on the proposed analysis, it will be possible to improve the inspection efficiency of the cyber security vulnerability of the NPPs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3617-3624
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• 2013

Screen inspection system applied vision and laser scan technology which detect foreign materials caused fuel rod to be damaged, and which inspect fuel rod damage, bowing, distortion and grid damages, was developed to secure reliability and reproductivity of inspection method for nuclear fuel assembly during outage. In further, datum of inspection results will be continuously monitored and given understand the pattern of bowing and distorting for fuel assembly in reactor. Understanding of the pattern will be key technical information to avoid grid demage might be happened during refueling outage and provides important data base for safe operation of nuclear power plant in Korea and world wide.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2036-2037
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• 2008

An Emergency Diesel Generator (EDG) manufactured by a French company Wartsila SACM, is a tandem type engine, consisted of two 10 cylindered diesel engines on each side. Manual provided by the manufacturer states that engine bearing requires inspection every 15 years. However, it is difficult for an inspector to access through a manhole located in the lower compartment of engine. Furthermore, during a routine or scheduled maintenance, it is not possible to disassemble main engine bearing and crank shaft, and perform inspection. Two methodologies are suggested here to resolve the problem. One method is to lift the engine and partially perform the maintenance service, and the other method is to disassemble the engine completely and to perform maintenance service by the manufacturer. Pros and cons of two methodologies were thoroughly compared.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.370-371
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.943-944
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• 2005

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.186-196
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• 2004

In each country, the periodic ISI(In-Service Inspection) is required by the law to protect the public health and property from the potential accident of the nuclear facilities. To support the implementation of ISI program, the prescriptive ISI technical standards have been established. As the key parts of the ISI program, the non-destructive examination techniques are widely used to identify the degree of degradation of the pressure boundary components and welds. Recently, the risk informed-ISI program has been developed and implemented in several countries. Nonetheless, the existing ISI program which prescriptively decides the scope of inspection still has its own significance. In this article, the technical standards of ISI in leading countries like US, france, Canada, and Japan are reviewed and compared with the safety guide by IAEA. An outline to revise the domestic technical standards of ISI has been suggested.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.1
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• pp.38-44
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• 2003

Performance demonstration with real flawed specimens has been strongly required for nondestructive evaluation of safety class components in nuclear power plant. Mechanical or thermal fatigue crack and intergranular stress corrosion cracking could be occured in the in-service nuclear power plant and mechanical fatigue crack was selected to study in this paper. Specimen was designed to produce mechanical fatigue flaw under tensile stress. The number of cycles and the level of stress were controlled to obtain the desired flaw roughness. After the accurate physical measurement of the flaw size and location, fracture surface was seal-welded in place to ensure the designed location and site. The remaining weld groove was then filled by using gas-tungsten are welding(GTAW) and flux-cored arc welding(FCAW). Results of radio graphic and ultrasonic testing showed that fatigue cracks were consistent with the designed size and location in the final specimens.