Electrical and mechanical properties of thermoplastic polyimide‐insulated coaxial cable for use under high‐temperature and radioactive conditions

Thermoplastic polyimide-insulated coaxial cable for use under high-temperature and radioactive conditions was developed and its electrical and mechanical properties were evaluated in comparison with cable insulated with polyetheretherketone which is known for its superior heat- and radiation-resistant characteristics. According to experiments, the electrical properties of thermoplastic polyimide-insulated cable are stable over a wider temperature range in comparison with polyetheretherketone-insulated cable even after 1.2 MGy of γ-ray irradiation and 6-months heat aging at 220°C, indicating that thermoplastic polyimide is superior for use as a heat- and radiation-resistant cable-covering material. The electrical properties of TPI cable observed, were within actual use requirements, even under γ-ray irradiation up to 1000 Gy/h.