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Benchmark Analysis for Condition Monitoring Techniques of Aged Low Voltage Cables in Nuclear Power Plants
Closed for proposals
Project Type
Project Code
I21021CRP
1733Approved Date
Status
Start Date
Expected End Date
Completed Date
11 November 2015Description
The overall objective of the CRP is the establishment of quantitative evaluation methodology for continued operations beyond 50~60 years in nuclear power plants. The results of the CRP will be used in assessing the long term reliability of passive systems, structure and components (SSCs), management of age-related degradation issues, and application of new technologies for monitoring, diagnostics and performance prediction. This will substantially contribute to better technical support of NPP operation safety and life management for long term operations.
The proposed life limited technical issues will be focused in the CRP as follows:
Intensive ageing management programme
Reactor pressure vessel
Reactor pressure vessel internals
Cable ageing management
Concrete structures
Material issues
Non-destructive examination
Objectives
The overall objective of the CRP is the establishment of quantitative evaluation methodology for continued operations beyond 50~60 years in NPPs. The results of the CRP will be used in assessing the safe long term operation of passive systems, structures and components (SSCs), management of age-related degradation issues, and application of new technologies for monitoring, diagnostics, and performance prediction. This will substantially contribute to better technical support of NPP operation safety and life management for long term operations (LTO)
Specific objectives
The CRP’s specific objectives are 1) Prioritizing broadly-defined research areas that address long-term challenges to plant operations; 2) Developing prioritized research areas and identifying cross-cutting topics of relevancy;4) Establishing responsible organizations and their research area;5) Compiling research results and suggesting the resolution to each main topic; and 6) Incorporating relevant information from related ongoing international activities (International Forum for Reactor Ageing Management, Life Beyond 60 Program and LWR Sustainability Program).Additionally, the CRP is intended to provide a starting point for future discussions on specific ageing-related research and managerial topics to develop a detailed implementation roadmap proposing research activities that may provide a better understanding of ageing and degradation behaviour before extending reactor’s lifetime beyond 50~60 years.
The specific objectives are: Prioritizing broadly defined research areas that address long-term challenges to plant operations; Developing prioritized research areas and identifying cross-cutting topics of relevancy;Establishing responsible organizations and their research areas;Compile research results and suggest resolution to each main topic; and Incorporate relevant information from related ongoing international activities (International Forum for Reactor Ageing Management, Life Beyond 60 Program and LWR Sustainability Program Life Beyond 60 Program and LWR Sustainability Program).
Impact
The CRP established a benchmarking programme in which cable samples were donated by manufacturers, aged under thermal and radiation conditions, and tested before and after ageing by various organizations and according to different methods. The results of these tests were then compared to identify the proper condition monitoring techniques and to establish recommendations for improvements to these methods. In particular, 12 types of cable insulation or jacket material were tested, each using 14 different condition monitoring techniques. Condition monitoring techniques yield usable and traceable results. Techniques such as elongation at break, indenter modulus, oxidation induction time and oxidation induction temperature were found to work reasonably well for degradation trending of all materials. However, other condition monitoring techniques, such as insulation resistance, were only partially successful on some cables and other methods like ultrasonic or Tan Gwere either unsuccessful or failed to provide reliable information to qualify the method for degradation trending or ageing assessment of cables. The electrical in situ tests did not show great promise for cable degradation trending or ageing assessment, although these methods are known to be very effective for finding and locating faults in cable insulation material. In particular, electrical methods such as insulation resistance and reflectometry techniques are known to be rather effective for locating insulation damage, hot spots or other faults in essentially all cable types. The advantage of electrical methods is that they can be used for in situ testing of installed cables while a nuclear power plant is operating. This publication is an update of IAEA-TECDOC-1188 and of the information in IAEA Nuclear Energy Series No. NP-T-3.6, and it describes the fundamentals of cable performance and condition monitoring techniques. It identifies the condition monitoring techniques that show potential for further development and eventual implementation into a cable ageing management programme.
Relevance
NA