Control test of neptunium extraction at Tokai reprocessing plant

Nagaoka, Shinichi ; Morimoto, Kazuyuki; Kitao, Takahiko ; Obu, Tomoyuki; Kanamori, Sadamu; Omori, Eiichi

4050% of neptunium (Np) was distributed to product stream in Tokai Reprocessing Plant (TRP) at present. We tried to increase acidity of second extraction cycle within available operating parameter, and by measuring neptunium concentration at outlet stage in second extraction cycle, we verified that 6070% of neptunium was distributed to product stream. Also we warmed up solutions in contactors of second extraction cycle within available operating parameter to make sure oxidation of neptunium on actual process, and we verified that 70% of neptunium was distributed to product stream. We confirmed that increasing acidity and warming up solutions was effective for Pu-U-Np co-extraction on the engineering scale reprocessing facility.