Thermophysical properties of rock-like oxide fuel with spinel–yttria stabilized zirconia system

• Published in: Journal of nuclear materials Vol. 274; no. 1; pp. 15 - 22
• Main Authors: Nitani, N., Yamashita, T., Matsuda, T., Kobayashi, S.-i., Ohmichi, T.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-08-1999; Elsevier
• Subjects: Applied sciences; Energy; Exact sciences and technology; Fuels; Nuclear fuels; Preparation and processing of nuclear fuels; M03; C11; T06; P04; Vickers hardness; Stability; Creep; Oxides; Nuclear fuel; Experimental study; Multiphase system; Zirconia; Spinel; Thermal conductivity; Plutonium; Yttrium; Melting point; Thermophysical properties
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/S0022-3115(99)00077-X

Thermal expansion, thermal diffusivity, melting temperature, Vickers hardness and creep rate of the rock-like oxide (ROX) fuel were measured with the MgAl
2O
4(spinel)–ZrO
2(Y,Gd) (YSZ: stabilized zirconia) system and the MgAl
2O
4–YSZ–UO
2 system in the temperature range between room temperature and 1800 K in order to evaluate thermophysical properties. Thermal expansion coefficients of MgAl
2O
4–YSZ composites increased with increasing YSZ content and the values were well represented by the Turner's equation. Addition of UO
2 to MgAl
2O
4–YSZ composite resulted in an increase of thermal expansion. Thermal conductivity values of the MgAl
2O
4–YSZ composites decreased with increasing YSZ content and agreed with predictions of the Maxwell–Eucken equation. The eutectic temperature of MgAl
2O
4–YSZ and MgAl
2O
4–YSZ–UO
2 systems was found to be 2200 K. High temperature hardness of the composites was higher than that of YSZ or MgAl
2O
4. The hardness of ROX fuel was considerably higher than that of UO
2. The creep rate of MgAl
2O
4–YSZ composite was controlled by the lattice diffusion of YSZ.