Modified TTA method for the determination of plutonium

The spent fuel from Fast Breeder Test Reactor of various burnups from 25 to 155 GWd/te is being reprocessed in CORAL (COmpact Reprocessing of Advanced fuels in Lead shielded cell) using a modified PUREX (Plutonium Uranium Recovery by EXtraction) process. Total plutonium (Pu238, 239, 240, 241 & 242) concentration in the sample is analysed by HTTA (Thenoyl Trifluoro Acetone) extraction method wherever interference from other alpha emitting nuclides (Raffinate) and bulk natural uranium (uranium products) are present "as reported by Milyukov et al. (Analytical chemistry of plutonium, 1967) and Natarajan and Subba Rao (BARC, pp. 38–43, 2007)". This method requires the addition of corrosive reagents such as NH2OH.HCl which is a problem in waste disposal for reduction. A salt-free reagent such as Hydroxyurea is studied as a reducing agent which has the ability to reduce both Pu(VI) and Pu(IV) to Pu(III) "as reported by Zhaowu (260(3):601–606, 2004) and Zhaowu (262(3):707–711, 2004)". Pu(III) thus formed can be easily oxidised to Pu(IV) by NaNO2 for the extraction of Pu by HTTA.