Nuclear fuel cycle thermal reactor

Nuclear fuel cycle, 881-996, 883-963 thermal reactor, 883 Nuclear fuels... 

Abstract The chapter is devoted to the practical application of the fission process, mainly in nuclear reactors. After a historical discussion covering the natural reactors at Oklo and the first attempts to build artificial reactors, the fimdamental principles of chain reactions are discussed. In this context chain reactions with fast and thermal neutrons are covered as well as the process of neutron moderation. Criticality concepts (fission factor 77, criticality factor k) are discussed as well as reactor kinetics and the role of delayed neutrons. Examples of specific nuclear reactor types are presented briefly research reactors (TRIGA and ILL High Flux Reactor), and some reactor types used to drive nuclear power stations (pressurized water reactor [PWR], boiling water reactor [BWR], Reaktor Bolshoi Moshchnosti Kanalny [RBMK], fast breeder reactor [FBR]). The new concept of the accelerator-driven systems (ADS) is presented. The principle of fission weapons is outlined. Finally, the nuclear fuel cycle is briefly covered from mining, chemical isolation of the fuel and preparation of the fuel elements to reprocessing the spent fuel and conditioning for deposit in a final repository. 

FIG. XIX-4. Nuclear fuel cycle scheme for a nuclear energy system with thermal reactors (TRs) andfast reactors (FRs) of the SVBR type with direct utilization of the thermal reactors ... 

The R D performed has demonstrated technical feasibility and potential economic competitiveness of the SVBR-75/100 reactor installations for nuclear power systems of both near and far future. The modular structure of NSSS of a power unit with SVBR-75/100 reactor installations makes it possible to reduce the NPP construction period and, in the future, to make a transfer to the standardized design of power units of different capacity on the basis of the serially produced standard modules offering a broad spectrum of inherent safety features. Such approach will assure competitiveness of the NPPs not only in electricity markets but in investment markets as well. Power units with SVBR-75/100 could be used in both developed and developing countries. For SVBR-75/100 it is possible to use different types of fuel and to operate reactor in different fuel cycles, preferably the ones that turn to be more efficient at certain moments of nuclear power evolution. When operating under a closed nuclear fuel cycle, it is possible to assure fuel self-supply regime or to provide a small breeding. The SNF of thermal nuclear reactors may be utilized as a make-up fuel for SVBR-75/100. 

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