Defined by statute (the Nuclear Waste Policy Act) to mean the highly radioactive waste material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that contains fission products nuclides in sufficient concentrations; and other highly radioactive material that the US Nuclear Regulatory Commission (NRC), consistent with existing law, determines by rule requires permanent isolation. The NRC has not defined sufficient concentrations of fission products or identified other highly radioactive material that requires permanent isolation. The NRC defines high-level radioactive waste (HLW) to mean irradiated (spent) reactor fuel, as well as liquid waste resulting from the operation of the first cycle solvent extraction system, the concentrated wastes from subsequent extraction cycles in a facility for reprocessing irradiated reactor fuel, and solids into which such liquid wastes have been converted. For a specific NEPA document, an additional statement can be included. Note: DOE usage generally follows the NWPA definition. Thus, high-level radioactive waste does not include spent nuclear fuel, but refers to liquid wastes from reprocessing of spent nuclear fuel and targets and the solid (vitrified) waste forms into which such liquid wastes are converted. It is desirable to provide the NRC definition, too, because it is used in NRC regulations that apply to geologic waste repositories and other facilities for management of commercial spent nuclear fuel and high-level waste. In some DOE NEPA documents this term refers only to liquid high-level waste or only to vitrified high-level waste