Abstract
Electrical cables in nuclear power generating stations are demanded to have a high reliability. For further improvement of the reliability, the development of nondestructive diagnoses seems desirable for maintenance of cables. The authors have been studying the residual voltage for developing a diagnosis of electrical cables. The purpose of this paper is to give a foundation for development of diagnostic technology for detecting the irradiated degradation; we studied the relations between γ-irradiation dose and the leakage current, the discharge current, and the residual voltage. We have tried to calculate the amount of. polarized charge and characteristic dielectric relaxation time for distribution of relaxation times by using data on the residual voltage. The calculated results agreed with the results obtained from the leakage current and the discharge current. These results suggest that we can employ the residual voltage in diagnostic technology for detecting the irradiated degradation.
