U.S.-French cooperative research program: U.S. test results for cable insulation and jacket materials at the completion of accelerated aging

Eight different U.S. insulation and jacket products have been accelerated aged at Sandia. We investigated two ethylene propylene rubber (EPR), two cross-linked polyolefin (XLPO), two TEFZEL, one chlorinated polyethylene (CPE), and one chlorosulfonated polyethylene (CSPE) material. Each of the sample specimens was produced by disassembling commercial U.S. Class 1E electrical cables. The experimental variables included: (1) sequential versus simultaneous accelerated aging exposures; (2) the order of the sequential exposures; and (3) ambient versus 700C irradiation temperatures during sequential aging exposures. We observed that the irradiation temperature (700C or ambient) was secondary in importance to the choice of sequence for thermal and radiation aging. For most materials studied (except TEFZEL) the irradiation then thermal aging sequence was as severe or more severe than the thermal then irradiation aging sequence. 8 figs.