The thermal conduction behavior of the neutron absorbing ceramic boron carbide in the initial stage of the irradiation was analyzed and a classical thermal conduction model was used to estimate the variation of the thermal conductivity in this paper. The calculated thermal conductivity using the model shows a large degration in the initial stage of irradiation. As the burnup increases, the thermal conductivity turns to be free of temperature dependence. These calculated results are consistent well with the expermental data of thermal conductivity of the irradiated boron carbide, which may suggest that the variation of the thermal conductivity of boron carbide is predominantly determined by the point defects scattering in the initial stage of irradiation.

The grain size dependence of the bulk resistivity of 3 mol% yttria-stabilized zirconia at 1400°C was determined from the effect of a dc electric field Ea=18.1 V/cm on grain growth and the corresponding electric current during isothermal annealing tests. Employing the brick layer model, the present annealing test results were in accordance with extrapolations of the values obtained at lower temperature employing impedance spectroscopy and 4-point-probe dc. The combined values give that the magnitude of the grain boundary resistivity ρb=133 ohm-cm. The electric field across the grain boundary width was 28–43 times the applied field for the grain size and current ranges in the present annealing test.

Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.

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