Thermal diffusivity and conductivity of thorium–plutonium mixed oxides

• Published in: Journal of nuclear materials Vol. 416; no. 1; pp. 135 - 141
• Main Authors: Cozzo, C., Staicu, D., Somers, J., Fernandez, A., Konings, R.J.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-09-2011; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Heat treatment; Thorium oxide; Laser; Thermal conductivity; Thermal diffusivity; Plutonium; Radiation damage; Nuclear reactor; Crystalline structure
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2011.01.109

The thermal diffusivity of (Th,
Pu)O
2 (with 3, 8 and 30
wt.% PuO
2) mixed oxides and of the single oxides PuO
2 and ThO
2 was measured using the laser flash technique. In several samples, a further degradation in the thermal diffusivity due to auto-irradiation damage was noted, and a recovery could be achieved by thermal treatment. The ThO
2 and (Th,
Pu)O
2 samples with 3 and 8
wt.% PuO
2 were found to be semitransparent and had to be coated with C for the thermal diffusivity measurement. The experimental thermal conductivity of the fuels was calculated and analysed. The introduction of PuO
2 in the ThO
2 was found to have an effect similar to that observed in (U,
Pu)O
2 mixed oxides: small decrease in the range 3–8
wt.% PuO
2 and higher decrease at 30
wt.% PuO
2 content. Using the classical phonon transport model in crystal structures, a new correlation for the thermal conductivity of (Th,
Pu)O
2 mixed oxides is proposed and is compared to the results of another correlation built after the Klemens–Callaway theory.