SIDEBAR 1.1: The definitions of HLW in the United States and Russia differ from each other.
Russia’s waste classes are based on the concentration of radioactivity in the waste (Rybal’chenko et al. 1998) or on the dose rate at the surface of the waste package (NAS 1990).
The United States’ definition is based on the process that produced the waste, although it allows for other wastes to be grouped with HLW on a case-by-case basis. High-level radioactive waste is
“(A) the highly radioactive 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 in sufficient concentrations; and (B) other highly radioactive material that the (Nuclear Regulatory) Commission, consistent with existing law, determines by rule requires permanent isolation.” [42 U.S.C. § 10101]
The U.S. Nuclear Regulatory Commission has defined spent nuclear fuel as high-level waste [10 CFR 63]. Spent nuclear fuel is fuel that has been withdrawn from a nuclear reactor following irradiation.