Reprocessing fuel cycle

The second option is the reprocessing fuel cycle. Unlike the once-through option, with reprocessing the fuel cycle is actually closed since the unused fissile... 

Reprocessing fuel cycle (RFC) with mixed oxide (MOX) recycle of U and Pu in light water or fast breeder reactors (FBRs) and disposal of HLW. 

In the Reprocessing Fuel Cycle (RFC) option, the unused uranium and the plutonium produced in the reactor are recovered leaving the minor actinides with the fission products as HLW. (The radiotoxicity of these wastes will be significantly less than that of the spent fuel although the toxic lifetime is determined by the minor actinides - neptunium, americium, curium - and, to a lesser extent, by some of the long-lived fission products content of the waste.) As mentioned previously, this was the scenario initially envisioned by the nuclear power industry to reprocess fuel for two reasons ... 

The throwaway fuel cycle does not recover the energy values present ia the irradiated fuel. Instead, all of the long-Hved actinides are routed to the final waste repository along with the fission products. Whether or not this is a desirable alternative is determined largely by the scope of the evaluation study. For instance, when only the value of the recovered yellow cake and SWU equivalents are considered, the world market values for these commodities do not fully cover the cost of reprocessing (2). However, when costs attributable to the disposal of large quantities of actinides are considered, the classical fuel cycle has been the choice of virtually all countries except the United States. 

Prospects in the United States for deploying breeders on a large scale were bright when it was beHeved that rich uranium ore would be quickly exhausted as use of nuclear power expanded. The expected demand for uranium was not realized, however. Moreover, the utiliza tion of breeders requires reprocessing (39). In 1979 a ban was placed on reprocessing in the United States. A dampening effect on development of that part of the fuel cycle for breeder reactors resulted. The CRFBP was canceled and France and Japan became leaders in breeder development. 

Development efforts in the nuclear industry are focusing on the fuel cycle (Figure 6.12). The front end of the cycle includes mining, milling, and conversion of ore to uranium hexafluoride enrichment of the uranium-235 isotope conversion of the enriched product to uranium oxides and fabrication into reactor fuel elements. Because there is at present a moratorium on reprocessing spent fuel, the back end of the cycle consists only of management and disposal of spent fuel. 

This facility design concept was not considered in White House reviews of reprocessing during the Ford and Carter Administrations, nor as an option for support by President Reagan, who had been elected on a platform to support reprocessing of commercial spent firel. The ERDA and the DOE had reassigned responsibilities for commercial fuel cycle to its Division of Reactor Development (later Office of Nuclear Energy) which supported pilot plant concepts of its national laboratories and rejected concepts based on successful experience and lessons learned from that experience. 

If nonproliferation considerations have not led to official opposition to nuclear power, their effect on fuel cycle policy has been profound. Although, its rhetoric and many of its implementating actions have been more restrained, the Clinton Administration has, in principle, adopted the Carter policy of opposition to reprocessing and plutonium recycle, hr at least one important area, however, it has inexplicably out-Cartered earlier policy by terminating work on proliferation-resistant firel cycles that involve recycle of still highly radioactive plutonium. 

Nuclear fuel cycle, 77 545-547 safety principles and, 17 546-547 Nuclear fuel reprocessing, 10 789-790 Nuclear fuel reserves, 17 518-530 alternative sources of, 17 527 economic aspects of, 17 526-527 toxicology of uranium, 17 528-529 uranium mineral resources, 17 518-521, 522-525... 

Meanx hile, success in the development of the natural uranium fuelled CANDU concept had led to very low cost fuelling and effective utilization of uranium even without recovery through reprocessing. AECL therefore decided to set aside work on reprocessing and concentrate instead on the once-through fuel cycle with storage of the irradiated fuel. The evidence indicated that the zirconium clad UO fuel could be stored under water for many decades until a decision was needed regarding recycle or disposal. 

Fig. 1. Schematic illustration of the ideal closed nuclear fuel cycle (NRC 2003). In real practice, the reprocessing capacity does not match the generation rate of the spent nuclear fuel. Thus, the excess SNF must be placed in interim storage or disposed of in a geological repository. Under normal circumstances, the SNF will be in interim storage for just a few years. Also, note that excess material from nuclear weapons, e.g.. highly enriched 235U and 239Pu, can be blended down to lower concentrations and used as a reactor fuel.

Fig. 2. Schematic illustration of the ideal open nuclear fuel cycle (NRC 2003). In this case, there is no reprocessing. Interim storage may last for tens of years so that the heat and radioactivity are much less prior to handling and final disposal. The spent fuel still contains fissile nuclides, such as 235U and 239Pu (generated by neutron capture reactions with 238U).

---