A method for providing a nuclear fuel includes forming a uranium-molybdenum alloy that provides an enhanced reactivity in research, test and radioisotope production nuclear reactors. In this uranium-molybdenum alloy, the uranium is enriched in the isotope 235-U, while the molybdenum is depleted in the isotope 95-Mo. The thus obtained enhanced reactivity can have at least two advantages, depending on the exact use of the fuel element: a requirement for less uranium in the fuel and the use of the fuel elements during a longer period in the reactor.