Reactor fuel cycle

A variation of the classical fuel cycle is the breeder cycle. Special breeder reactors are used to convert fertile isotopes iato fissile isotopes, which creates more fuel than is burned (see Nuclear reactors, reactor types). There are two viable breeder cycles U/ Pu, and Th/ U. The thorium fuels were, however, not ia use as of 1995. A breeder economy implies the existence of both breeder reactors that generate and nonbreeder reactors that consume the fissile material. The breeder reactor fuel cycle has been partially implemented ia France and the U.K. 

Wymer, R. G. Vondra, B. L. Eds. Light Water Nuclear Reactor Fuel Cycle CRC Press Boca Raton, Florida, 1981. 

Takata, T., Koma, Y., Sato, K. et al. 2004. Conceptual design study on advanced aqueous reprocessing system for fast reactor fuel cycle. J. Nucl. Sci. Technol. 41 (3) 307-314. 

R. G. Wymer, B. L. Vondra, Technology of the Light Water Reactor Fuel Cycle, CRC Press, Boca Raton, FL, 1980... 

In the case of a nuclear accident, most of the radioisotopes in the environment and food can be reliably and quickly assayed by gamma spectroscopy. There is a problem with some important isotopes which are pure beta or alpha emitters and which cannot be identified directly by gamma spectroscopy. The activity of the isotopes of the strontium group Sr, Sr and Y after a three-year reactor fuel cycle can reach about 8% of the total in-core activity and one of them, Sr(Y), is important for the long-term health consequences. 

Basile, A. et al., Membrane integrated system in the fusion reactor fuel cycle. Catalysis Today, 25, 321, 1995. 

Fuel cycles utilizing this method of reprocessing will extend our uranium reserves, decrease the spent fuel storage requirements and decrease the amount of waste requiring storage in a Federal Repository for environmental isolation. AIROX reprocessing is applicable to both light-water reactor fuel cycles as well as fast breeder fuel cycles. 

Table 9.13 lists the isotopes of plutonium important in nuclear technology and some of their important nuclear properties. Plutonium isotopes are produced in reactors by the nuclide chains shown in Fig. 8.5. Typical quantities and isotopic compositions of plutonium in various reactor fuel cycles are listed in Tables 8.4, 8.5,8.6, and 8.7. In reactors fueled with uranium and plutonium, Pu is the principal isotopic constituent, but Pu contributes the greatest amount of alpha activity. With U-thorium fueling, Pu is the principal isotopic constituent. 

There are two breeder reactor fuel cycles. One involves the irradiation of U/ Pu oxide fuel with fast neutrons and is at the prototype stage of development. The other involves the irradiation of Th/ U oxide fuel with thermal neutrons and is at the experimental stage. Fuel from the U/ Pu cycle may be reprocessed using Purex technology adapted to accommodate the significant proportion of plutonium present in the fuel. Increased americium and neptunium levels will also arise compared with thermal reactor fuel. The Th/ U fuel may also be reprocessed using solvent extraction with TBP in the Thorex (Thorium Recovery by Extraction) process. In this case the extraction chemistry must also take account of the presence of Pa arising as shown in Scheme 2. 

The Experimental Breeder Reactor-II (EBR-II) was designed as a 62.5 MWt, metal fueled, pool reactor with a conventional 19 MWe power plant. The productive life of the EBR-II began with first operations in 1964. Demonstration of the fast reactor fuel cycle, serving as an irradiation facility, demonstration of fast reactor passive safety and lastly, was well on its way to close the fast breeder fuel cycle for the second time when the Integral Fast Reactor program was prematurely ended in October 1994 with the shutdown of the EBR-II. 

Moreover, there is a potential application of polymeric membranes for integrated gasification combined cycle (IGCC) power plants, some aspects of the integration of a membrane reactor with a fuel cell, the possibility to integrate a membrane reformer into a solar system, and the potential application of membrane integrated systems in the fusion reactor fuel cycle, which are attracting many scientists and so will also be introduced and discussed in this chapter. 

Membrane integrated system in the fusion reactor fuel cycle... 

Violante, V., Basile, A., Drioh, E. (1993). Membrane separation technologies their apph-cation to the fusion reactor fuel cycle. Fusion Engineering and Design, 22, 257. 

More recent studies have been related to the fast reactor and light-water reactor fuel cycles. 

Ellis, C. and Baxter, A.M. 2004. Modular helium reactor fuel cycle concepts and sustainability. HTR China Proceedings, 2004. Tsinghua University, Beijing, China. 

To close the fast breeder reactor (FBR) fuel cycle, a fast reactor fuel cycle facility (FRFCF) has long been planned, with construction originally to begin in 2008 and operation to coincide with the need to reprocess the first prototype fast breeder reactor (PFBR) fuel. The PFBR and the next four FBRs to be commissioned by 2020 will use oxide fuel. After that, it is expected that metal fuel with higher breeding capability will be introduced and burn-up is intended to increase from 100 to 200 GWd H. 

The first fuel assemblies containing plutonium from PFR recycled into new oxide were loaded into PFR in June 1982, therd>y closing the reactor fuel cycle. 

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