Hydrazine holding reductant

Hydrazine (N2H ) was found to be an effective scavenger of N02 ions and thus a promising holding reductant. Production scale tests at Hanford in 1968 with hydrazine-stabilized ferrous nitrate were plagued by problems associated with the carryover of nitrite, though the soundness of this method was demonstrated (3). 3+... 

Hydroxylamine nitrate (HAN) requires addition of hydrazine as a holding reductant, to prevent destruction of hydroxylamine by the nitrous acid present as a result of radiolysis, in the reaction... 

In the IB column remaining traces of plutonium are stripped from the solvent by a strippant IBX, stream 10, containing hydrazine as holding reductant. A decontamination factor of 200 for removal of plutonium from uranium is anticipated for the IB columns. The big advantage of this partitioning system is that it adds no nonvolatile materials such as ferrous sulfamate to the system. 

Plutonium reduction. Reduction of plutonium to Pu(III) is completed by adding concentrated hydroxylamine (with hydrazine as holding reductant) to the aqueous raffinate leaving the HC column. The mixture must be held long enough, half an hour or more [B2], to complete the rather slow reduction to Pu(III). To hasten the reaction, the hydroxylamine concentration should be high and the nitric acid concentration as close to 0.3 M as possible without risking plutonium polymer formation. 

During electrolytic reduction of to and the subsequent reduction of Pu to inextractable Pu hydrazine is added as a holding agent to destroy excess nitrite ions and prevent reoxidation of and Pu to their higher valence states. 

Before being fed to Contactor III, the aqueous feed solution was treated to reduce Pu to the Pu(III) state, to prevent its extraction and ensure its recovery in the aqueous Pu product stream (3PP). The reference reductant for the flow sheet was hydroxyla-mine nitrate (HAN) at 0.3 mol/L with hydrazine nitrate (0.1 mol/L) as a holding agent or HNO2 scavenger (10). Use of HAN as Pu reductant was considered desirable because in reaction with Pu, as well as in subsequent reactions where the reductant is destroyed, only gaseous products are formed (equations 1 and 2). 

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