Flowsheet partition cycle

More recently a flowsheet has been developed which employs 30% TBP/OK as the solvent.349-446 447 This involves the use of an acid feed to the first cycle to assist in zirconium decontamination and suppress hydrolysis. An acid-deficient partition cycle then follows in which the U-Th separation is effected. A pilot plant (JUPITER) has been constructed at Julich in Germany to process Th02/U02 fuel using this flowsheet. Although a complete separation of thorium, uranium and FPs is possible using TBP in the Thorex process,448 alternative approaches... 

The partition cycle columns were operated on flowsheet values and then a DBP solution was pumped to the extraction feed point in increasing amounts. The thorium content of the uranium product stream from the thorium partition column was monitored. The runs were then repeated using increasing increments of fluoride in the thorium partition solution and the thorium content again monitored in the uranium product from the partition column. 

Figure 2. Acid-Thorex partition cycle flowsheet...

The Purex Process has been used either with "early" or with "late" Pu-U partitioning (Fig. 1). The early split in the first cycle avoids the co-stripping of uranium and plutonium which may result in higher plutonium losses. In other flowsheets, the partitioning is delayed until the second cycle. While no particular trend has been obvious, some of the recent flowsheets in which the plutonium is reduced prior to re-extraction (10,11) will necessarily require a second cycle partitioning. 

Early solvent extraction flowsheets for HTGR fuels recycle developed at the General Atomic Company contained a coextraction costrip cycle for thorium and uranium prior to the partitioning... 

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