Microstructural study of gamma phase stability in U–9wt.% Mo alloy

Density-functional study of bcc U–Mo, Np–Mo, Pu–Mo, and Am–Mo alloys

“…Together with our ab initio results obtained previously for U-Mo, U-Am, Pu-U, Pu-Np, and Pu-Am alloys [2,9,11,19,49] these new results will be used to build a thermodynamic database for U-TRU-Mo alloys that are considered to be very promising fuels for fast breeder reactors [4,[50][51][52][53][54][55][56]. …”

Assessment of effective thermal conductivity in U–Mo metallic fuels with distributed gas bubbles

“…1 and TEM results [1], the gas bubble structure evolution is roughly separated into two different stages, i.e., before and after recrystallization. Before recrystallization, intragranular gas bubbles remain small (around 2 nm in diameter), but gas bubble density increases as a result of continuous high-energy particle radiation-induced dissolution of larger gas bubbles and the continuous nucleation of gas bubbles.…”

“…The gamma U phase is retained by Mo in solid solution that possesses acceptable irradiation stability, mechanical properties, and corrosion resistance, and is formed over a wide range of Mo concentration [1,2]. However, the formation and growth of fission gas bubbles in irradiated nuclear fuels is of technical importance because it may impact the thermo-mechanical properties, hence, fuel performance.…”

A machine learning approach to thermal conductivity modeling: A case study on irradiated uranium-molybdenum nuclear fuels

“…Mo is selected as a major alloying element in the range of 8-10 weight percent (wt%) to stabilize the high temperature body centered cubic (BCC) gamma-U phase (γ-U), while also achieving the desired high U density and high thermal conductivity [12]. Stabilization of the BCC γ-U phase is essential to achieving desired fuel performance because γ-U has acceptable swelling, mechanical stability, and corrosion resistance when subjected to neutron irradiation [10,11,13]. When U is unalloyed, the alpha-U phase (α-U) is stable at lower temperatures (up to 667°C); α-U has an orthorhombic crystal structure, and thus experiences anisotropic thermal expansion which could lead to swelling under neutron irradiation at the elevated temperatures typical of a reactor environment [11].…”

“…Stabilization of the BCC γ-U phase is essential to achieving desired fuel performance because γ-U has acceptable swelling, mechanical stability, and corrosion resistance when subjected to neutron irradiation [10,11,13]. When U is unalloyed, the alpha-U phase (α-U) is stable at lower temperatures (up to 667°C); α-U has an orthorhombic crystal structure, and thus experiences anisotropic thermal expansion which could lead to swelling under neutron irradiation at the elevated temperatures typical of a reactor environment [11]. While other transition metals could be used to stabilize the BCC γ-U phase, Mo is the most desirable candidate for achieving high U densities, and the selection of 8-10 wt% Mo alloying addition is a trade-off between γ-U phase stabilization and neutron penalty associated with Mo [12].…”