Loss-of-coolant accident (LOCA) simulation tests on polymers: the importance of including oxygen

Experiments were performed to survey the effects on material degradation of both aging conditions and the oxygen concentration during a LOCA simulation. Changes for a number of commercial materials commonly used as electric cable jackets and insulations in nuclear power plant applications were monitored in terms of weight, mechanical properties, solubility measurements and infrared spectroscopy. For a number of these materials (an EPR insulation, a chloroprene jacket and a PVC jacket), the concentration of oxygen during LOCA simulation was found to be an important parameter. For the first two materials, more degradation occurred when oxygen was present; for PVC, substantially increased swelling occurred as the oxygen concentration was lowered. Aging conditions were also found to have a very substantial influence. In particular, for a number of the materials, lowering the radiation dose rate used for aging led to enhanced degradation after both the aging and the LOCA simulation. The different materials examined showed very different behaviors in terms of the degradation resulting from aging and from LOCA simulation