Modeling of thermal and radiative aging of polymeric cable materials

It is of critical importance to safety in the nuclear power industry to estimate the lifetime of polymeric materials in an environment featuring elevated temperatures and radiation. To this end, the authors are examining the aging of polymeric materials, in cables and other components in nuclear reactor containments by comparing aging processes for a variety of materials under natural conditions with those under accelerated laboratory conditions typical of those used in qualification. The physical property data derived from naturally and artificially aged specimens are compared using three methods: (1) a traditional method; (2) activation energy from natural data alone; and (3) an internal standards method. All three methods work with the properties of the material in its aged, but usable state, and not with a failure time of the material.