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Purex disadvantages

Historically, the Redox process was used to achieve the same purification as in the Purex process (97,129). The reagents were hexone (methyl isobutyl ketone) as the solvent, dichromate as an oxidant, and A1(N02)3 as the salting agent. The chief disadvantages of hexone are its flammability and its solubihty in water. However, because A1(N03)3 collects in the highly radioactive waste, thereby impeding the latter s further processing, the Redox process was abandoned in favor of the Purex process. [Pg.201]

As in the Purex process, the Thorex process uses a solution of TBP in hydrocarbon diluent to extract the desired elements, uranium and thorium, from an aqueous solution of nitrates. Thorium nitrate however, has a much lower distribution coefficient between an aqueous solution and TBP than uranium or plutonium. To drive thorium into the TBP, the Thorex process as first developed at the Knolls Atomic Power Laboratory [HI] and the Oak Ridge National Laboratory [G14] added aluminum nitrate to the thorium nitrate in dissolved fuel. This had the disadvantage of increasing the bulk of the high-level wastes, which then contained almost as many moles of metallic elements as the original fuel. To reduce the metal content of the waste, the Oak Ridge National Laboratory in the late 1950s [Rl, R2] developed the acid Thorex process, in which nitric acid is substituted for most of the aluminum nitrate in the first extraction section. The nitric acid is later evaporated from the wastes, as in the Purex process. [Pg.514]

There are advantages and disadvantages to all of the processes just described. Some are easier to implement than others. Some require adjustment of parameters such as pH or nitrate concentration. Some have problems with third phase formation and solvent degradation or become impractical for industrial applications because of the limited loading capacities of the extractants. In all cases, however, adding separation steps to the PUREX process to remove the minor actinides will generate additional secondary waste streams that will have to be managed. [Pg.2827]


See other pages where Purex disadvantages is mentioned: [Pg.940]    [Pg.940]    [Pg.231]    [Pg.7085]    [Pg.397]    [Pg.411]    [Pg.413]    [Pg.86]   
See also in sourсe #XX -- [ Pg.291 ]




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