A possible version of the VVÉR-1000 fuel cycle without separation of uranium and plutonium during reprocessing of spent fuel is examined. In this fuel cycle, the uranium-plutonium regenerate obtained, from which other actinides and fission products have been removed, is used after enriched natural uranium is added for preparing VVÉR fuel. The results of a calculation of the content of uranium and plutonium isotopes in the spent uranium-plutonium fuel after one and two recycles in VVÉR-1000 are presented. The main advantages of the fuel cycle are discussed: lower risk of plutonium proliferation, savings of natural uranium, and less spent fuel as compared with an open uranium fuel cycle.In currently existing technology for reprocessing spent fuel, uranium and plutonium are divided into two fractions, which presupposes that the fractions have different uses. Thus, at the RT-1 plant the uranium regenerate separated during reprocessing of spent VVÉR-440 fuel is mixed with uranium obtained from spent BN-600 fuel, and used for fabricating RBMK-1000 fuel, which contains up to 2.6% 235 U. The same scheme is used to fabricate fuel for the experimental-industrial operation of fuel assemblies with regenerated uranium in VVÉR-440 and -1000 reactors [1]. The power plutonium, whose quantity has reached 30 tons [2, 3], separated during regeneration of uranium is accumulating. France has achieved substantial success in using regenerated plutonium in thermal reactors. Of the 11-12 tons of plutonium obtained by reprocessing spent PWR and BWR fuel, approximately 8.5 tons goes to fabricating mixed fuel, which is loaded into 30% of the core of 20 PWR [40].Other forms of fuel for burning regenerated plutonium are also being investigated [5]. One is plutonium dioxide, incorporated into an inert matrix, for example, zirconium oxide [6]. After irradiation, such fuel can be immediately sent into storage. A mixture of regenerated plutonium with enriched natural uranium with plutonium content ~2% has also been proposed. Such fuel can be loaded up to 100% into a PWR core [7,8].In France, regenerated uranium is partially loaded into PWR and BWR on an experimental-commercial scale. For additional enrichment, it is mixed with highly enriched weapons uranium [9] or enriched at an isotope-separation plant [2]. However, most of the regenerated uranium is stored.To simplify the reprocessing of spent fuel from the fast reactors which are being designed and to decrease the risk of plutonium proliferation, it has been proposed that uranium and plutonium be separated together [10]. The same approach is also possible for reprocessing fuel from thermal reactors. This will make it possible to return the regenerated uranium and plutonium into the fuel cycle. In the present article, one possible way of using regenerated uranium and plutonium in VVÉR-1000 reactors is examined.
