Lead-cooled fast reactors impose harsh environments on the structural materials, including high damage doses, high temperatures and corrosive liquid lead. To withstand these environments, advanced steel concepts, such as a composite of 15-15Ti and FeCrAl, has been proposed as fuel cladding. Microstructural evolution of alloys is governed by fundamental properties, including the vacancy formation and migration energy, yet such data for novel alloy compositions is sparse. In this work, an extensive set of the vacancy formation and migration energies in two alloys, 15-15Ti and FeCrAl, was calculated from first-principles, employing density functional theory. Special quasirandom structures were generated for both alloys, and different magnetic states of the alloys were simulated. It was found that the vacancy formation energy is highly influenced by the chemical and magnetic environment in 15-15Ti, while in FeCrAl the size-mismatch between Fe and the alloying elements dominates. The vacancy formation energy is calculated by two different density functional theory formulations, showing excellent agreement. The vacancy migration energy was found to be governed by the magnetic and chemical environment changing as the atom migrates. Based on these findings, temperature-averaged behaviors of vacancies in the alloys are derived, which can be further used to define effective vacancy formation and migration energies at reactor-relevant temperatures. The effective vacancy formation and migration energies can be used to predict temperature-variable shifts needed to accommodate the higher dose rate of ion irradiation, when attempting to emulate neutron irradiation.