STANDARDIZATION OF OXIDATION INDUCTION TIME TESTING USED IN LIFE ASSESSMENT OF POLYMERIC ELECTRIC CABLES

Oxidation induction time (OIT) has been proven to be a useful diagnost ic tool in assessing the extent of degradation in the polymer insulati on of electric cable in nuclear power plants. Factors that influence O IT include test temperature, sample preparation, sample geometry, samp le mass, particle size, thermogram interpretation, and shelf life. The effects of these parameters were investigated for ethylene propylene diene monomer (EPDM) and crosslinked polyethylene (XLPE) polymer cable insulations, which were aged in radiation and thermal environments. T he results were then used to recommend standards for an OIT methodolog y suited for practical use in the nuclear power industry. Techniques t o estimate error in thermogram interpretation and reproducibility were also developed. (C) 1997 John Wiley & Sons, Inc.