scholarly journals Condition Monitoring Uncertainties and Thermal - Radiation Multistress Accelerated Aging Tests for Nuclear Power Plant Cables: A Review

2019 ◽  
Vol 64 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Zoltán Ádám Tamus
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Thermal Radiation ◽  
Environmental Stress ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Low Voltage ◽  
Accelerated Aging ◽  
Radiation Environment ◽  
Insulation Material

The low voltage cables in the nuclear power plant have the same importance as veins have in the human body. Since, the cables inside the containment are under a number of environmental stress, out which the thermal and radiation stresses are important and become more effective with the presence of oxygen. These stresses cause the degradation of the insulation and hence may lead to insulation failure. To study the behavior of the cables under the nuclear power plant environmental stress, the cables are subjected to accelerated aging tests in laboratories which helps in determining their withstand capacity and degradation behavior in the harsh thermal-radiation environment. In this paper, the accelerated aging tests conditions are discussed with the focus on the role of certain uncertainty factors which effect the aging markers during the condition monitoring of the insulation material of cable after the accelerated aging tests. This review has been put into a framework to better understand the aging process in the low voltage nuclear power plant cables. In the conclusion part, some future directions in the field of the thermal-radiation multi-stress accelerated aging tests and condition monitoring techniques are also identified.

Analysis of the Degradation Tendency of NPP Cables Using a Wireless Cable Indenting Robot

2013 ◽  
Vol 284-287 ◽  
pp. 1749-1753
Author(s):  
Kyung Nam Jang ◽  
Jong Soeg Kim ◽  
Sun Chul Jeong ◽  
Kyung Heum Park ◽  
Sung Yull Hong
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Power Plants ◽  
Accelerated Aging ◽  
Test Equipment ◽  
Testing Time ◽  
Operation Period ◽  
Non Destructive

In nuclear power plants, there are many cables that perform safety-related functions. These cables should implement condition monitoring during the operation period in the nuclear power plant, in order to assess the remaining qualified life and extend the qualified life. In this study we focused on the indenting method which can measure the hardness of the cable jacket. This method is selected because it is non-destructive and requires short testing time and small sized equipment. In order to address the problems with the existing indenting test equipment, we developed new indenting test equipment, which could automatically move on the surface of the object cable. The newly developed equipment is designed for a small-sized and light-weight robot using wireless communication in order to implement condition monitoring in a harsh environment or locations that are inaccessible to the tester. The developed wireless cable indenting robot is composed of three parts, which are mechanical and electrical hardware parts and remote-control part. In order to analyze the degradation tendency of the cable, we prepared four thermally aged specimens and one un-aged specimen. Using the developed robot, we measured the modulus of the cable jacket of each specimen. The test data showed that the modulus of the cable jacket increased linearly as the accelerated aging time increased. From these results, we can analyze the degradation trends pertaining to cables installed in nuclear power plant according to the operation period.

scholarly journals Dielectric loss and extended voltage response measurements for low-voltage power cables used in nuclear power plant: potential methods for aging detection due to thermal stress

2020 ◽  
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Zoltán Ádám Tamus
Keyword(s):  
Thermal Stress ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Low Voltage ◽  
Voltage Response ◽  
Insulation Material ◽  
Power Cables ◽  
Response Measurement ◽  
Low Frequencies

Abstract This paper discusses the effect of thermal stress on the electrical properties, conduction and polarization, of low-voltage CSPE/XLPE-based power cables used in a nuclear power plant. The cables were subjected to an accelerated thermal stress at 120°C for an equivalent service period of 20, 40, 60 and 80 years. The capacitance, tanδ, resistivity at different frequencies and extended voltage response were the methods used for the investigation. A significant variation in the values of tanδ at low frequency, i.e., at 100 Hz, was observed. For the extended voltage response measurement, the decay voltage slope increased, showing the increase in the conduction particles inside the insulation material. While the decrease in return voltage slope showed that the slow polarization processes occurring at very low frequencies were decreased with aging. A strong correlation between the tanδ and decay voltage slope was also observed, which increased as the insulation aging increased. The results showed that the methods could be used for the in situ measurement of conduction and polarization phenomenon in the low-voltage cables, and hence helping in the assessment of the condition of cable insulation.

Qualification, Condition Monitoring, and Management of Ageing of Low Voltage Cables in Nuclear Power Plant

2015 ◽  
Author(s):  
Ki Sig Kang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Low Voltage ◽  
Ageing Time ◽  
Service Organizations ◽  
Energy Agency ◽  
Development Organization ◽  
Chemical Testing

The International Atomic Energy Agency (IAEA) organized an international Coordinated Research Project (CRP) on qualification, condition monitoring, and management of low voltage cables for life management in nuclear power plant. A total of 16 organizations from Technical Service Organizations (TSOs), and Research & Development Organization participated in the CRP and tested and presented their experimental results. The CRP members are actively engaged in providing cable samples, thermal and radiation ageing of cables, and electrical, mechanical, and chemical testing of cables samples. Preliminary analysis of the test data received show that, for some of the Condition Monitoring (CM) methods, good correlation is observed with ageing time and there is consistency in measurements between the different test labs carrying out the tests. The level of correlation with ageing time and the degree of variability between labs is dependent on the material being tested and the CM method being used.

Condition Monitoring of a Nuclear Power Plant Check Valve Based on Acoustic Emission and a Neural Network

2005 ◽  
Vol 127 (3) ◽  
pp. 230-236 ◽  
Author(s):  
Min-Rae Lee ◽  
Joon-Hyun Lee ◽  
Jung-Teak Kim
Keyword(s):  
Neural Network ◽  
Acoustic Emission ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Failure Modes ◽  
Check Valve ◽  
Flow Loop ◽  
Artificial Neural

The analysis of acoustic emission (AE) signals produced during object leakage is promising for condition monitoring of the components. In this study, an advanced condition monitoring technique based on acoustic emission detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant. AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network.

Development of Robots Working in High Radiation Environment for Decommissioning Fukushima Daiichi Nuclear Power Plant

2018 ◽  
Vol 2018.23 (0) ◽  
pp. A112
Author(s):  
Takuya FUKUMOTO ◽  
Kouji ISHIZAWA ◽  
Satoshi OKADA ◽  
Katsuhiko HIRANO ◽  
Kouichi KUROSAWA ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Radiation Environment ◽  
High Radiation ◽  
Fukushima Daiichi
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