Electrical conductivity of proton conductive ceramics under reactor irradiation

Possibility of converting radiation-energy such as energy of gamma-rays directly into electricity was surveyed with proton conductive ceramics in a fission reactor. Proton Conductive Ceramics, SrCe_0.95Yb _0.05O_3-δ, BaCe_0.9Y_0.1O _3-δ, and CaZr_0.9In_0.1O _3-δ were irradiated in a fission reactor, JMTR and their electrical conductivity and radiation induced electrical motive force were measured under irradiation. On some of specimens, a hydrated zirconium electrode was attached for studying effects of hydrogen on the electrical conductivity and the radiation induced electromotive force. An increase of the electrical conductivity was clearly observed at higher temperatures in specimens with a hydrated electrode. The experimental results are indicating that the electron conductivity is dominant below 400K and the conventional radiation induced electrical conductivity, whose magnitude is nearly proportional to the electronic excitation dose rate of radiation field, was observed. In the meantime, the base electron conductivity will be reduced by the radiation effects. Above 450-480K, the protonic conductivity is dominant in the present proton conductive ceramics and enhancement of proton diffusion was taking place under the irradiation. Increase of the electromotive force by the existence of hydrogen was not clearly observed in the present study, however, there was some possibility of contribution of the proton conduction to the RIEMF above 450K.