Thermal and diffusional properties of (Th,Np)O2 and (U,Np)O2 mixed oxides

Evidence of vacancy ordered structures in PuO2−x and AmO2−x from first-principles calculations

“…The propensity of minor actinides (MAs: Np, Am, Cm) to transmute in fast reactors can reduce the long-term radiotoxic inventory of high-level nuclear waste. [1][2][3][4] Smaller amounts of MAs (up to 5%) can be added to uranium-plutonium mixed oxide fuels, while higher amounts can be added to blankets that contain MAs (like (U,Am)O 2Àx ) or specifically designed transmutation fuels or targets (like (Pu,Am)O 2Àx in MgO or Mo matrices). 1 Since 241 Am will always be present as a daughter of 241 Pu, (U,Pu)O 2Àx is also thought to be a potential driver fuel to burn MAs.…”

“…Cluster expansion of AnO 2ÀxFor the CE of PuO 2Àx and AmO 2Àx , 31 and 44 structures are considered for the calculations with DFT which give a crossvalidation score of 21.1 and 26.0 meV, respectively. The number of clusters (pairs, triplets and quadruplets) used are(11,4,1) and(19,11,4) for PuO 2Àx and AmO 2Àx , respectively. The CE method is implemented to calculate the mixing energy (DE mix ) considering structures with 12 or fewer cation sites.…”