Study of Radiation Induced Electrical Degradation of Alumina in a Dynamic Pumping Condition in a Fission Reactor

概要

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The electrical conductivity of two ceramic insulators, alumina, and silicon nitride was measured in a fission reactor, JMTR under a dynamic vacuum condition. The instrumented irradiation rig was dynamically evacuated during fission reactor operation. The uppermost vacuum level attained was better than 10^<-2> Torr. In this experiment, we attempted to reveal effects of the gaseous environment on the measurement of electrical conductivity under ionizing irradiation. The results showed that the gaseous environment has a most hazardous effect in a certain gas pressure range. In the second experiment, an electrical resistivity of polycrystal α-alumina was measured at about 680K in a dynamic pumping condition. In a good vacuum, we observed smaller RIC(radiation induced conductivity) than our previous results. We observed RIED(radiation induced electrical degradation)-like behavior. The results suggested that RIED would take off faster at a higher ionizing dose rate. In the meantime, the take-off occurred at about the same displacement damage of about 0.03-0.05dpa in the range of fast neutron flux of 3.4-15.1x10^<13>n/cm^2s.electrical conductivityα-aluminasilicon nitridegaseous environmentin-reactor measurement in a dynamic vacuum
東北大学の論文
1994-09-16