Recycled uranium

Nuclear fuel reprocessing was first undertaken with the sole purpose of recovering plutonium, for weapons use, from uranium irradiated in nuclear reactors. These reactors, called the production reactors, were dedicated to transmuting as much of the uranium as possible to plutonium. From its original scope of recovering exclusively plutonium, with no attempts to either recover or recycle uranium, nuclear fuel reprocessing has since grown into a much more sophisticated and complex operation with expanded scope. It is now called upon to separate uranium and plutonium from the fission products, and to purify these elements to levels at which these fissile materials can be conveniently recycled for reuse. The present scope also extends to fission products separation and concentration. 

BJC/PORTS. 2000. Recycle Uranium Mass Balance Project, Portsmouth, OH, Site Report. Bechtel Jacobs Company LLC, BJC/PORTS-139/R1. 

Recently much attention has been given to the accelerator driven systems, burning in inert matrices, and the use of thorium to burn plutonium. The concept of a closed nuclear fuel cycle was traditionally considered as transmutation (burning) of only plutonium and recycled uranium, with minor actinides (neptunium, americium, curium) destined for final geological disposal. But as time goes on, a new understanding is emerging reduction of the quantity of actinides would ease requirements for final repositories and make them relatively less expensive. 

Cartmell, H. R. Ellis, J. F. Process and apparatus for the manufacture of uranium hexafluoride from recycled uranium trioxide. Fr. Demande 90-3100. Chem Abstr 1990, 114, 84812. 

Ammonium carbonate in the eluate is removed by steam stripping and then recycled. Uranium in the steam-stripped eluate is concentrated further by conventional anion exchange. 

Reactor type Fuel PWR Uranium (3.3% U) PWR Uranium and recycled plutonium HTGR U, thorium, and recycled uranium LMFBR Uranium and recycled plutonium... 

N22 = initial amount of U, which may be finite due to recycled uranium It has been assumed that no Pa is recycled. Because the concentration of is much less than that of thorium in uranium-thorium thermal reactors, (n, 2n) reactions in have been neglected. 

In the case of equilibrium recycle, the concentration of in the discharged thorium is the same as that in the makeup thorium containing the recycled uranium. In Fig. 8.12 this concentration is shown as a function of the total flux time of the fuel irradiation. However, during irradiation the in the fuel decreases below its initial concentration and then recovers as Pa is formed. 

For that portion of the separated thorium that is eventually to be recycled and blended with the recycled bred uranium, less time for thorium storage is possible. A reasonable criterion is that the thorium be stored for a sufficient period such that its Th activity is equal to the activity of Th in the recycled uranium at the time of fabrication. Ignorirtg process losses, the recycled bred uranium contains all of the that was present in the discharge thorium. If this recovered uranium has been stored for a time Tp prior to fuel fabrication, the activity of Th in the uranium is... 

Neptunium concentration in fuel from thermal reactors could be increased by recycling uranium containing U. 

In the thorium fuel cycle the recycled uranium-233 inevitably is contaminated with uranium-232 and its decay products. The first of these, thorium-228, will be contained in any recycled thorium. Thallium-208 in this decay chain emits a very-high-energy gamma ray and for this reason fabrication of recycle fuels in the thorium fuel cycle will have to be done remotely in heavily shielded cells. Conventional fuel febri-cation processes may not be the most economical under these conditions. 

Some countries, e.g., France, Japan, Russia, and the United Kingdom have chosen to reprocess their spent nuclear fuel to recycle uranium and plutonium as nuclear fuel and to obtain a high active waste (HAW) firaction that is less radiotoxic than the spent fuel itself. In this process, very high separation factors are necessary. The fission product activity has to be reduced by a factor of > 10 and the separation factor between uranium and plutonium must be at least 2 x lO. All full-scale reprocessing processes are based on solvent extraction, and today the plutonium uranium redox extraction (PUREX) process dominates the market completely. 

These data are much lower (by several orders of magnitude), than reported for DU from an unfired CHARM-3 penetrator [34] and indicates that there may be substantial variation in the concentrations of transuranic elements, fission products, and non-natural uranium isotopes in batches of DU over time. Reported data on measured 238pu/239,24opu activity ratio, at 0.036 0.002, is typical of low bum-up plutonium and would confirm that recycled uranium had been used for the production of weapons-grade plutonium [101]. 

US DOE (1999) News release R-99-262 of September 29, 1999, Past recycled uranium programs under review as Energy Department Investigation Continues available at http // www.energy.gov/HQPress/releases 99/seppr/pr99262. htm... 

Recycled uranium and plutonium from spent fuel as mixed oxide (MOX) fuel... 

Technology for recycling uranium recovered from UNE from Chinese PWRs for use in the Qinshan Phase III Candu units is being developed. 

The use of SEU (or recycled uranium, RU, from reprocessing spent PWR fuel) in current HWR designs offers many benefits, and in many countries having such HWRs one would anticipate that enrichment will be introduced in the near future. 

Cottrell, C.M., M. Boubcher, M. Chen, Z. Zhang, and S. Kuran, 2013. Natural Uranium Equivalent (NUEO Fuel Full Core Use of Recycled Uranium and Depleted Uranium in CANDU Reactors, Proceedings of the 21st International Conference on Nuclear Engineering (ICONE 21), Chengdu, China... 

Transuranic nuclides and their daughters, e.g. Am, Np and Pa, in recycled uranium and material contaminated by it. 

Each of three successive, major, worldwide Precambrian orogenies about 2500, 1800 and 1000 m.y. ago recycled uranium and thorium by magmatic-anatectic reworking of rocks of its predecessors and their erosional products. Con-... 

However, in the case of mixed oxide fuel, the new fuel may be radioactive as a result of the recycled plutonium it contains and, in some fuels, recycled uranium may be used. In this case, the new fuel will be a significant source of both neutrons and gamma rays and it will need to be shielded and contained at all times until it is inserted into the reactor. The magnitude of the neutron source term will depend upon the time that has elapsed since the plutonium was created, since actinides that emit neutrons will be produced as the plutonium decays. 

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