Radiation enhanced diffusion of hydrogen in perovskite-type oxide ceramics under reactor irradiation

Electrical conductivity of yttrium-doped perovskite-type barium-cerium oxide ceramics (BaCe_0.9Y_0.1O_3-δ), implanted with 10 keV H₂⁺ ions, was measured in situ under fission reactor irradiation. An increment of the electrical conductivity, called radiation induced conductivity (RIC), was observed with increasing ionizing dose rate. The RIC for the specimen with implanted H at 1.1 kGy/s and irradiation temperatures 473-673 K was higher by about four orders of magnitude than the base conductivity without radiation at 0 Gy/s, and was about two orders of magnitude higher than that without H. The RIC is attributed to electronic excitation as well as hydrogen enhanced diffusion. The RIC greatly depended on the irradiation temperature, but was insensitive to the fast neutron fluence in the range 3.3-7.4 × 10²³ n/m². The results show that the radiation induced defects, produced by neutron collisions, and radiolysis have no influence on the electronic and protonic conduction.