[en] The cost-benefit analysis of closed UO₂, U and Th fuel cycles of the WWER-1000 reactor has been performed. Major characteristics of the fresh and spent fuels are presented. The costs of the external fuel cycle S include the costs of chemical reprocessing, fuel shipment, radioactive waste disposal and fuel fabrication from the recycled fuel. The economic efficiency of the spent fuel reprocessing at S= 50-300 doll/kg and natural uranium Csub(E) and separative work unit Csub(SWU) costs ranging from 18 to 100 doll/kg and from 18 to 54 doll/kg, respectively, has been calculated. At the present day level of Csub(E)=30-40 doll/kg the marginal values of S when the reprocessing is still economical, amounted to 235, 148 and 41O doll/kg for the UO₂, U and Th fuel cycles respectively. The effect of the reprocessing on the share of fuel costs in the total electricity generation costs has been also analyzed at Csub(E)=36 doll/kg, Csub(SWU)=41 doll/kg and at Csub(E)=100 doll/kg, Csub(SWU)=54 doll/kg. The reprocessing is totally concluded to be economical for the WWER type reactors with UO₂, U and Th fuel cycles in the wide range of S