Relation of containment capacity with phase composition, density and Vickers hardness of simulated waste forms Gd2-xNdxZr2O7(Nd=An(Ⅲ), 0≤ x ≤ 2.0)

Abstract

In order to investigate the capability of Gd2Zr2O7 pyrochlore as a waste form for immobilizing trivalent actinides nuclides, Nd(Ⅲ) is used as an alternative substance for An(Ⅲ). The compounds in the system Gd2-xNdxZr2O7 (0≤ x ≤ 2.0) are synthesized at 1500 ℃ for 72 h by high temperature solid state reaction method, using Gd2O3 and ZrO2 powders as the raw materials. The phase, intensity, Vickers hardness and microcosmic shape are characterized by X-ray diffraction, Vickers hardness tester, scanning electron microscopy and so on. The results indicate that the phase of synthesized waste form with plate-shape keeps the phase of pyrochlore. The intensity of compound slightly decreases with the increase of the containment capacity value x, but it is above 5.76 g·cm-3. The value of Vickers hardness also decreases with the increase of x. The values of x and Vickers hardness are linearly related by HV=695.18636-162.64091 x (HV≥ 400 kg·mm-2).