Sufficiently cheap isotope separation could assist in practical aspects of nuclear energy. For example, fuel rod cladding for fission reactors could be made with separated isotopes of elements that normally are not considered, because some of their isotopes absorb neutrons too strongly. These elements could be more resistant to damage in accidents than zirconium, which evolves hydrogen when sufficiently hot in contact with steam. Fusion reactors would also benefit from materials with lower neutron activation.