[en] Effect of spent nuclear fuel (SNF) bum-up on Purex-process flowsheet structure during fuel reprocessing with the use of diluted tributyl phosphate (TBP) is discussed. The necessity o overall long-lived radionuclide partitioning, starting from head-end process stages, has been shown, including U and Pu to be utilized. The partitioning is followed with localization of Np and TPE, as well as fission-born Tc, Zr, and Mo. Russian flowsheets of Modified Purex are demonstrated, which make possible total recovery of Zr and/or Np and Tc, along with U and Pu. Zirconium salt of dibutyl phosphoric acid (ZS-HDBP). dissolved in 30% TBP, is proposed as a Purex-compatible solvent for recovery of TPE, as well as Zr and Mo, to form, in combination with Modified Purex flowsheet, a kind of Superpurex process. (authors)