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Advanced Fission Technologies and Systems
Published in William J. Nuttall, Nuclear Renaissance, 2022
The issues surrounding Urep re-use, however, are not simply a matter of re-enrichment. Urep is a very different precursor for fuel manufacture than Unat. For example, reprocessed uranium can contain problematic elements and isotopes such as residual fission products that have not been completely removed in reprocessing.
The Environment Today
Published in Anco S. Blazev, Power Generation and the Environment, 2021
There are also a number of modified PUREX processes, such as UREX (URanium EXtraction) process, which is used to save space inside high-level nuclear waste disposal sites. Here, the uranium which makes up the vast majority of the mass and volume of used fuel is removed and recycled as reprocessed uranium.
Nuclear Fuel Recycling
Published in Kenneth D. Kok, Nuclear Engineering Handbook, 2016
Patricia Paviet, Michael F. Simpson
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).
Double Cascades for Purification of Reprocessed Uranium Hexafluoride from 232, 234, 236U Isotopes
Published in Nuclear Science and Engineering, 2022
Valerii Palkin, Eugene Maslyukov
The accumulation of reprocessed uranium obtained from the irradiated fuel of nuclear light water reactors, like the Russian VVER, raises a number of practical problems to be solved. One of them is the reuse of reprocessed uranium for nuclear fuel breeding. The concentration of 235U basic fissile matter in it is higher than that in natural uranium.1 However, reprocessed uranium contains 232, 234, 236U harmful isotopes, which hamper its reuse. The 232, 234U isotopes in low-enriched uranium (where the 235U concentration is less than 5%) considerably worsen the radiological environment during nuclear fuel manufacture. A high concentration of 236U in the fuel leads to the increase of the parasitic capture of neutrons, and therefore to the necessity to increase the concentration of 235U as a compensating measure. Different methods of separating reprocessed uranium hexafluoride in the cascades and dilution procedures2–8 have been developed in order to reduce the concentration of 232, 234, 236U. They have certain advantages and drawbacks. The latter imply the enrichment of reprocessed uranium at high 235U concentrations exceeding 90%, the use of natural and waste uranium at the additional feed of the cascades, and the use of low-enriched output as a diluting agent. A common thing for these methods is the noncompliance with American Society for Testing and Materials (ASTM) C996-20 international specification standards for the low-enriched commercial grade of uranium hexafluoride.