Aging Assessment of Nuclear Generating Station Cables

Abstract

A number of diagnostic techniques requiring micro samples for monitoring the condition of nuclear generating station cables have been identified. The cables studied were insulated with polyethylene (PE), cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), butyl rubber, styrene butadiene rubber (SBR), and polyvinyl chloride (PVC). The degradation was assessed by conventional elongation measurement, differential scanning calorimeter(DSC) oxidation induction time (OIT), DSC oxidation induction temperature (under high oxygen'pressure), infrared carbonyl absorption, density, and swelling measurements. The sensitivities of the diagnostic techniques to measure oxidation and embrittlement were compared with the elongation results, and a criterion for monitoring the cable degradation was developed. Range of values obtained using diagnostic techniques are presented which can be used to assess the degradation state of commonly used insulating materials.