Oxygen Chemical Diffusion Coefficients of (U, Pu)O_2-x

Abstract

The oxygen chemical diffusion coefficient in (U, Pu)O2-x was determined by thermo-gravimetry as functions of the Pu content, oxygen-to-metal ratio and temperature. The surface reaction was considered in the diffusion coefficient determination. The activation energy for the chemical diffusion coefficient was 60 kJ/mol and 65 kJ/mol, respectively, in (U0.8Pu0.2)O2-x and (U0.7Pu0.3)O2-x.

Cation interdiffusion in uranium–plutonium mixed oxide fuels: Where are we now?

“…Indeed, oxygen chemical diffusion in AnO 2±x was shown to be enhanced at compositions close to O/M = 2.00 (Chereau and Wadier, 1973;Sari, 1978;Bayoǧlu and Lorenzelli, 1979;Bayoǧlu and Lorenzelli, 1984;Stan and Cristea, 2005) as a result of preponderant clustering when the deviation from stoichiometry is increased. This observation remains under discussion among the community as some other studies suggest either an increase or a stagnation in the oxygen chemical diffusion coefficient when the deviation from stoichiometry is increased (Woodley and Gibby, 1973;Kim and Olander, 1981;Kato et al, 2013;Vauchy et al, 2015b;Watanabe et al, 2015;Watanabe et al, 2017).…”

Oxygen diffusion in the fluorite-type oxides CeO2, ThO2, UO2, PuO2, and (U, Pu)O2

“…Previous studies have measured oxygen self-diffusion and chemical diffusion coefficients (Watanabe et al, 2017;Vauchy et al, 2015;Sari, 1978;Murch and Catlow, 1987;Lorenzelli and El Sayed Ali, 1977;Kato et al, 2013;Kato et al, 2009;Garcia et al, 2010;Deaton and Wiedenheft, 1973;D'Annucci and Sari, 1977;Contamin et al, 1972;Breitung, 1978;Belle, 1969;Bayoglu and Lorenzelli, 1984;Bayoglu and Lorenzelli, 1979;Auskern and Belle, 1961;Ando et al, 1976;Watanabe and Kato, 2012;Kim and Olander, 1981;Floyd, 1973;Kamiya et al, 2000;Millot and Mierry, 1985;Gotte et al, 2007). The oxygen diffusion coefficients data set used in this review is shown in Table A1.…”

“…The data were measured using various methods, such as the isotope method, thermogravimetry, electrical conductivity measurement, and thermal dilatometry. It was difficult to assess changes dependent on temperature and O/M ratio because the data were scattered (Floyd, 1973;Gotte et al, 2007;Kamiya et al, 2000;Millot and Mierry, 1985;Ando et al, 1976;Dornelas and Lacombe, 1967;Matzke, 1987;Ligeon et al, 1970;Dorado et al, 2011;Lay, 1970;Bittel et al, 1969;Ruello et al, 2004;Kato et al, 2013;Mullins, 1972;Deaton and Wiedenheft, 1973;Bayoglu et al, 1983;Bayoglu and Lorenzelli, 1979;Chereau and Wadier, 1973;Bayoglu and Lorenzelli, 1980;Bayoglu and Lorenzelli, 1984;D'Annucci and Sari, 1977;Kato et al, 2009;Watanabe et al, 2017;Watanabe et al, 2020;Vauchy et al, 2015).…”

“…in the oxides at O/M = 2.00 were evaluated (Andersson et al, 2009;Zhang et al, 2019;Zamzamian et al, 2022). Of these oxides, the Q sto of ThO 2 was Watanabe et al (2017) and Kato et al (2009), and closed blue symbols were reported by Watanabe et al (2020). Closed black symbols were reported by Vauchy et al (2015), which were measured data in U 0.55 Pu 0.45 O 2 .…”