Thermal expansion of PuO2

Lattice thermal expansion of Pu1−y Am y O2−x plutonium–americium mixed oxides

“…As a second assumption, we suppose that the O/M ratio is also a linear function of the americium content in the Pu 1Ày Am y O 2Àx mixed oxides in both the temperature and composition ranges selected. It is also reasonable, and consistent with the literature (Brett & Russell, 1960;Nutt & Tokar, 1972;Tokar et al, 1973;Yamashita et al, 1997;Uchida et al, 2014), to estimate that the pure plutonium dioxide remains stoichiometric, i.e. O/Pu = 2.00, regardless of the temperature in the present experimental conditions.…”

“…their oxygen/metal (O/M) ratio is equal to 2.00 in the present conditions. This statement is consistent with the known lattice and macroscopic thermal expansion behaviour of stoichiometric PuO 2 (Brett & Russell, 1960;Nutt & Tokar, 1972;Tokar et al, 1973;Yamashita et al, 1997;Uchida et al, 2014). Nevertheless, if Pu 0.923 Am 0.077 O 2Àx were heated at higher temperatures, the deviation from the linear trend would be expected to appear more distinctly, similarly to what is observed in the samples exhibiting a greater americium content.…”

“…More precisely, thermal expansion behaviour is a key property for evaluating fuel-cladding interactions under irradiation (Fee & Johnson, 1981;Crawford et al, 2007;Olander, 2009;Gué neau et al, 2012;Lee et al, 2013). Since most of the current nuclear reactors operate with uranium dioxide or uranium-plutonium mixed oxide fuel (known as MOX), thermal expansion of these materials has been investigated for decades (Baldock et al, 1966;Martin, 1988;Momin et al, 1991;Yamashita et al, 1997;Tsuji et al, 2002;Uchida et al, 2014;Kato et al, 2016). To our knowledge, no similar studies have been performed on plutonium-americium mixed oxides, probably as a result of both the scarcity of these samples and the intrinsic difficulty in handling such radiotoxic MA-bearing solids in a glove-box.…”

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

“…4 shows the Pu content dependence of thermal expansion for (U,Pu)O 2.00 . The data of UO 2 and PuO 2 were measured with the same apparatus as in previous reports [12,18]. In the high temperature range above 1500 K, U 0.7 Pu 0.3 O 2 had the highest thermal expansion.…”

“…(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.…”