Actinides reprocessing irradiated nuclear fuel

RepU that is defined as uranium recovered from reprocessed irradiated nuclear fuel (also known as spent fuel) and thus will contain artificial uranium isotopes like U and (and also traces of other actinides and fission products) or SEU for slightly enriched uranium that contains 0.9%-2.0% of... 

Viewed in the context of the actinide lifespan, the nuclear fuel cycle involves the diversion of actinides from their natural decay sequence into an accelerated fission decay sequence. The radioactive by-products of this energy producing process will themselves ultimately decay but along quite different pathways. Coordination chemistry plays a role at various stages in this diversionary process, the most prominent being in the extraction of actinides from ore concentrate and the reprocessing of irradiated fuel. However, before considering these topics in detail it is appropriate to consider briefly the vital role played by coordination chemistry in the formation of uranium ore deposits. 

The major interest of the actinide-based alloys is due to applications in the nuclear industry for example, the interest in metallic fuels for liquid-metal fast breeder reactors and the interest in high-temperature techniques for the reprocessing of irradiated nuclear fuel have always persisted. 

Actinides occurrence and preparation. With the exception of U and Th, the availability of the actinides of the first half of the series ranges from the g to kg scale that of the elements of the second half of the series from the mg scale for Cf to the sub-mg scale for Es. Isotopes of Np, Pu, Am, Cm can be available as byproducts of nuclear fuel processing other elements such as Ac, Cf, Bk, Es can be obtained by irradiation of selected isotopes in high flux reactors, or by reprocessing large quantities of ore (Pa). 

The reprocessing involves separating the fission products from the actinides, and then separating the plntoninm from the uranium. The best known procedure of this type is the PUREX (Plutonium, URanium Extraction) process that is used for recovery of uranium and plutonium from irradiated fuel (see details in Chapter 2). The separated plutonium can be used for the production of nuclear weapons or converted into the oxide form, mixed with nraninm oxide and can be used as MOX nuclear fuel. 

The operations and facilities include ore exploration (not included in NFCIS list), mining, ore processing, uranium recovery, chemical conversion to UO2, UO3, UF4, UFg, and uranium metal, isotope enrichment, reconversion of UF to UO2 (after enrichment), and fuel fabrication and assembly that are all part of the front end of the NFC. The central part of the NFC is the production of electric power in the nuclear reactor (fuel irradiation). The back end of the NFC includes facilities to deal with the spent nuclear fuel (SNF) after irradiation in a reactor and the disposal of the spent fuel (SF). The spent fuel first has to be stored for some period to allow decay of the short-lived fission products and activation products and then disposed at waste management facilities without, or after, reprocessing to separate the fission products from the useful actinides (uranium and plutonium). Note the relatively large number of facilities in Table 2.1 dedicated to dealing with the spent fuel. Also listed in Table 2.1 are related industrial activities that do not involve uranium, like heavy water (D2O) production, zirconium alloy manufacturing, and fabrication of fuel assembly components. 

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