Modelling and assessment of thermal conductivity and melting behaviour of MOX fuel for fast reactor applications

Electron correlation and relativistic effects on the electronic properties of a plutonium and americium mixed oxide (PuAmO4): from single-particle approximation to dynamical mean-field theory

“…For Am ions, the mixed-valence state arises from the mixture of Am 3+ (5f 6 ) and Am 4+ (5f 5 ). For PuAmO 4 , the mixed-valence states of Pu/Am ions are similar to those of actinide ions in TM-doping uranium-based oxides, 52,62 (Th, U)O 2+x mixed oxides, 63 as well as the molecular solids Pu 3 (DPA) 5 (H 2 O) 2 and Pu 3 (DPA) 6 H. 64 In PuAmO 4 , the electron transitions such as 5f 4 -5f 5 for Pu ions and 5f 5 -5f 6 for Am ions would yield two absorption lines due to the SOC interactions of Pu and Am ions. 33,65 The X-ray absorption branching ratio or the relative strength of the absorption lines is generally proportional to SOC strength in the 5f shell.…”

“…Within the nuclear industry, recycling and burning minor actinides such as americium (Am) in mixed-oxide (MOX) nuclear fuel could be identified as an ultimate goal of Generation IV fast reactors, transmutation reactors, and/or acceleratordriven systems, 1,2 given the nuclear waste management and the optimal utilization of nuclear fuels. 3 In fact, for (Pu, Am) MOX, Am-doping would affect the micro-and macroscopic properties, such as the chemical stability, melting temperature, thermal conductivity, and oxygen potential, 2,4 which are essential for long-term storage, safety operation and development of advanced fast reactor fuels and nuclear waste reprocessing. 1,5 In addition, the oxidation and reduction behaviors are closely related to the oxygen potential, oxygen to metal ratio (O/M), 6 oxidation states of Pu/Am cations, 2 and the crystal structure in (Pu, Am) MOX.…”

Analysis of fabrication and crack-induced porosity migration in mixed oxide fuels for sodium fast reactors by the finite element method

“…to account for burnup would be straightforward and could rely, for example, on the recent work published by Magni and coworkers [34]. It is worth noticing that redistribution of plutonium would occur and influence the local thermal conductivity (directly and affecting the oxygen-to-metal ratio), but we are not accounting for this phenomena in the proposed model since we focus more on providing a robust and consistent modeling of pore migration, rather than a comprehensive fuel behavior module.…”