Investigation and life expectancy prediction on poly(ether-ether-ketone) cables for thermo-oxidative aging in containment dome of nuclear power plant

As a special engineering material, poly(ether-ether-ketone) (PEEK) wires and cables are widely applied in the containment vessel of nuclear power plant and vulnerable to long-term cumulative effects of multiple complex factors. Wherein, thermo-oxidative aging in high temperature environment for a long time is the key factor to lead to the degradation even failure of PEEK cables. Therefore, in this work, PEEK cables were subjected to thermo-oxidative aging for different times at 310 °C and the effects on the physicochemical properties of PEEK were investigated. Furthermore, the aging life expectancy of PEEK cables was effectively predicted by the innovative artificial accelerated aging model with breaking elongation as evaluation parameter. The results revealed the thermal stability and crystallinity of PEEK samples declined significantly with the extension of aging time. Prolonged thermo-oxidative aging can accelerate the oxidation decomposition and change the sample morphologies. Moreover, the scratch resistance and bending strength of PEEK cables were significantly weakened after 480 h aging. The final prediction suggested that the service life expectancy of PEEK cable samples can reach 73 years at the working temperature of 90 °C.