Radiation-Resistant Electrical Insulation Materials for Superconducting Magnet Applications

To develop radiation-resistant electrical insulation materials suitable for cryogenic temperatures and applications that require radiation resistance such as future nuclear fusion energy systems, a United States Department of Energy Fusion Energy Sciences funded study was undertaken collaboratively by InnoSense LLC (ISL) and the Center for Advanced Power Systems. The goals for the new electrical insulation materials were low gas generation under irradiation, long pot life, high mechanical strength, good flexibility, and high dielectric strength. The development of proprietary metal oxide nanoparticle incorporated organic polymer composites (MOPOC) and their properties are reported. MOPOC consists of organic polyurethane (PU)-polyimide (PI) copolymers, ISL's proprietary and patented phenylated bipyridinium ionic polymers, and metal oxide nanoparticles. The results show the promise of the materials with the desired characteristics of mechanical, thermal, and pot life. Dielectric strength of 44 kV/mm and the suitability for cryogenic temperature application was demonstrated by room temperature and 77 K measurements. Preliminary gamma radiation exposure tests are promising. Further systematic investigations with larger doses on multiple compositions are planned in the next phase of the development with the extension of funding from the Department of Energy Fusion Energy Sciences and the established extended collaboration with the University of California Davis for neutron and proton beam exposure of the insulation samples.