Reprocessed uranium

Unlike other primary energy sources, the global consumption of uranium exceeds its production. Worldwide consumption in 2005 amounted to 66 500 tU (NEA/ IAEA, 2006b).9 As Fig. 4.3 shows, newly mined and processed uranium (primary supply) exceeded reactor-related uranium requirements until 1991. Since 1991, the gap between primary supply and uranium demand has been filled by secondary supply, i.e., material that has been held in inventory (both civilian and military in origin) or has been reprocessed. Besides reprocessed uranium and plutonium of spent... 

The major use of C1F3 is in the nuclear industry which converts unclean spent fuel reprocessing, uranium metal into gaseous uranium hexafluoride. Other applications are low temperature etchant for single crystalline silicon [63,64], It is also used as a fluorinating reagent and in the synthesis of GIF and conversion of metals to metal fluorides such as tantalum and niobium metals to tantalum pentafluoride and niobium pentafluoride, respectively. 

M. SPENT FUEL REPROCESSED, URANiUM AND PLUTONiUM RECYCLED Recovered Pu, 445 kg... 

Figure 8.9 Principal contributions to the long-term ingestion toxicity of high-level waste from reprocessing uranium fuel (fuel from uranium-fueled PWR, 33 MWd/kg, 0.5 percent of uranium and plutonium appear in waste).

Table 11.3 Chemical composition of HAW concentrate from reprocessing uranium discharge fuel...

TABLE 21.7. Specifications for reprocessed uranium and plutonium (From IAEA 1977)... 

INTERNATIONAL ATOMIC ENERGY AGENCY, Interim Guidance for the Safe Transport of Reprocessed Uranium, IAEA-TECDOC-750, IAEA, Vienna (1994). 

For reprocessed uranium, Aj values may be calculated by using the equation for mixtures in para. 404 and taking account of the physical and chanical characteristics likely to arise in both normal and accident conditions. It may also be possible to demonstrate that the value is unlimited by showing that 10 mg of the uranium will have less activity than that giving rise to a committed effective dose of 50 mSv for that mixture. In addition, for calculating Aj values in the case of reprocessed uranium, the advice given in Ref. [8] may provide useful information. 

Reconstruction of pilot scale reprocessed uranium conversion facility was completed in June, 1994. 

Conversion test for reprocessed uranium was started in August, 1994. 

Fast reactor inculcation upon the nuclear power is also necessary if any country is guided by utilization of closed fuel cycle, when reprocessed uranium and plutonium serve as the efficient fuel for the NPPs with different reactor types. 

For reprocessed uranium to be used again in a reactor, it must again be enriched to about 3.5%. Because new uranium is in plentiful supply, it has not been necessary to re-emich uranium recovered from reprocessing to meet the requirements for new fuel. If and when it becomes necessary to enrich reprocessed uranium, the potential occupational hazard associated with UFe conversion, enrichment, and fuel fabrication processes due to the small amounts of residual fission products in the uranium will have to be addressed. 

Table 10 Composition of DU penetrator from reprocessed uranium...

Diehl P (2003) Hazards from depleted uranium produced from reprocessed uranium, WISE uranium project, fact sheet, available at http //www.antenna.nl/wise/uranium/pdf/durepe.pdf... 

A quantity of about 850 t of UO2 spent fuel is reprocessed annually in France according to Carre and Delbecq (2009), as a result of trade-off between optimizing plutonium recycling and power generation. Thus, about 100 t of MOX fuel are fabricated annually and recycled once into twenty 900 MW licensed reactors (30% of core), which contributes to about 10% of nuclear production. In the same way, reprocessed uranium (REPU) recovered from spent fuel is used today to fuel two 900 MW reactors, which may be expanded depending on the associated economic benefit (Figure 14.32). 

Finally, it should be noted that all the methods that rely on mass differaice, mass ratio, or kinetics to separate U-235 from U-238 will also lead to enrichment of U-234 (even to greater relative extent than U-235). Elevated levels of U-234 may complicate the utilization of the enrichment product. Similarly, use of reprocessed uranium that contains U-236 (and perhaps some U-232) may also affect the product quality. On the other hand, laser isotope separation methods will selectively enrich U-235 with only very slight changes in the U-234 and U-236 content. 

Facilities in which reprocessed uranium is converted to U3O8... 

IAEA-TECDOC-750. (1994). Interim guidance for the safe transport of reprocessed uranium. Vienna, Austria IAEA. 

Uranium is a naturally occurring radioactive element and, therefore, fresh nuclear fuel also contains radionuclides. Plutonium and reprocessed uranium, on the other hand, are accompanied by isotopes which were generated during the preceding exposure of nuclear fuel in a reactor. All the radionuclides present in fresh nuclear fuel are of minor importance in reactor operation nonetheless, they have to be taken into consideration in fuel fabrication in order to protect the employees from undue radiation exposure. 

Up to now, reprocessed uranium has only been used for the fabrication of a limited number of test fuel assemblies. For this type of fuel, the uranium fraction from the spent fuel reprocessing process is again subjected to an isotope enrichment procedure to obtain a content which is sufficiently high for reactor operation (3.8% in the example shown in Tables 3.1 and 3.2.). Besides the naturally occurring isotopes and this material contains mainly gener-... 

Likewise, the enhanced a activity of reprocessed uranium (greater by a factor of 4 to 10 than that of natural uranium) has to be considered in fuel manufacturing. The resulting complications can, in principle, be reduced by optimized fabrication logistics, so that the time elapse between isotope enrichment and insertion of the fuel into the reactor would amount to less than half a year. 

According to the generally accepted specifications, the maximum allowable content of residual fission products in the reprocessed uranium amounts to about 10% of the natural uranium activity as an upper limit for residual y-emitting fission products 1.1 10 MeV Bq/d kgU is usually specified. In most cases, the residual fission product activity in reprocessed uranium is below 1000 Bq/g. During the enrichment process of the reprocessed uranium the fission products behave in... 

The transuranium elements such as neptunium, plutonium or americium form hexafluoride compounds at their highest valency state with physical properties close to those of UF6 but these compounds are not stable when the fluorine partial pressme decreases. Under such conditions they are converted into a lower valency state and remain as a soUd product. This means that the main fraction of these impurities can be collected as ash or dust if there is still a small proportion remaining in the liquid UFe, it can be removed by a special filter before the container is filled. The specified upper limit for residual transuranium activity in the reprocessed uranium amounts to 2.5Bq/gU, with Pu, Pu and Np as the guide isotopes. 

Beck, M. Conversion of reprocessed uranium. Nuclear Europe V, (5), 32-34 (1985)... 

CEA and AREVA NC have developed and used a depletion code named CESAR for 30 years. This user-friendly industrial tool provides fast characterisations for all types of nuclear fuel (PWR / UOX or MOX or reprocess Uranium, BWR / UOX or MOX, MTR and SFR) and the wastes associated. CESAR can evaluate 100 heavy nuclides, 200 fission products and 150 activation products (with Helium and Tritium formation). It can also... 

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