Abstract: The invention refers to a nuclear fuel, a fuel element, a fuel assembly and a method of manufacturing a nuclear fuel. The nuclear fuel is adapted for use in a water cooled nuclear reactor, including light water reactors LWR, such as Boiling Water Reactors BWR and Pressure Water Reactors PWR. The nuclear fuel comprises an uranium-containing compound consisting of UN. The uranium content of the uranium-containing compound comprises less than 10% by weight of the isotope 235U. The nuclear fuel comprises an additive substantially consisting of at least one element, in elementary form or as a compound, selected from the group consisting of Zr, Mo, Si, Al, Nb and U.

Abstract: A method of making Gd or Er isotopes from gaseous compounds containing —BH4 and —CH3BH3 ions involves making the Gd or Er compounds (24) in a solid state reactor (10), passing the gaseous compounds (24) to a separation process (16) to provide products enriched in the desired isotopes of Gd or Er heads and Gd or Er tails depleted in these desired isotopes and then reacting the Gd or Er heads and Gd or Er tails with chlorine in a reactor (18) to provide products of 157GdCl3, 155GdCl3 or 167ErCl3 enriched in Gd and Er isotopes.