Neb. Rev. Stat. § 81-1589

High-level radioactive waste shall mean (1) irradiated reactor fuel, (2) liquid wastes resulting from the operation of the first cycle solvent extraction system or equivalent and the concentrated wastes from subsequent extraction cycles or equivalent in a facility for reprocessing irradiated reactor fuel, (3) solids into which such liquid wastes have been converted, and (4) other highly radioactive waste material as defined by the United States Nuclear Regulatory Commission.