Thermal expansion measurement and heat capacity evaluation of hypo-stoichiometric PuO2.00

Thermal expansion measurement of (U,Pu)O2-x in oxygen partial pressure-controlled atmosphere

“…Fig. 6 shows the O/M dependence of the CTE, and the data are in good agreement with those of PuO 2-x measured in the P O2 -controlled atmosphere [19]. The CTE slightly increased with decreasing O/M ratio.…”

“…(5), and coefficients a 0 , a 1 , a 2 and a 3 were obtained. Uchida et al [12,18] and Kato et al [19] reported thermal expansion and derived the equations for UO 2 and PuO 2 . Their data were reassessed by Eq.…”

“…The oxygen potentials at measurement temperatures were evaluated by Eqs. (1e3), which was described in details in previous works [19,23,24]. The thermal gravimeter was used to evaluate the O/M change during measurement.…”

Thermal and mechanical properties of CeO2

“…Relevant examples of this approach can be seen in measurements of thermal conductivity of hyperstoichiometric UO 2+ x or thermal expansion in hypostoichiometric PuO 2− x . While the oxygen potential of CeO 2 has been measured at temperatures of 1073‐1473 K in previous works, this study extends these measurements to a higher temperature range by a gas equilibrium method which was described in details in previous work . A thermodynamic model for the oxygen potential of CeO 2− x is then derived based on defect chemistry.…”

Study of thermodynamic properties of U1-yPuyO2 MOX fuel using classical molecular Monte Carlo simulations

“…Theoretically, heat capacity of actinide oxide and mixed oxide can be considered as the sum of several terms: heat capacity at constant volume 𝐶 , at which can be added a dilatation term 𝐶 , a Schottky term 𝐶 and a Frenkel term 𝐶 . Kato et al [88] showed that it is important to analyze the 𝐶 and 𝐶 terms in heat capacity of PuO 2 . An increasing PuO 2 heat capacity of about 10 J.mol -1 .K -1 when the temperature goes from 400 K to 1000 K as well as a rapid growth for temperatures above 1500 K has been observed adding 𝐶 and 𝐶 terms.…”