TETRAVALENT PLUTONIUM STABILIZATION IN NITRIC ACID SOLUTIONS Russian patent published in 2006 - IPC C01G56/00 

FIELD: electrochemistry.

SUBSTANCE: hydroxylamine is introduced into 0.5-3 M, preferably 1-2.5 M, nitric acid solution containing mixture of plutonium with different valence, namely Pu(VI), Pu(IV), and Pu(III). Solution is conditioned at 20-40°C, preferably at 25-35°C during period sufficient to reduce Pu(VI) to Pu(IV). Then nitric acid concentration is adjusted to 2.5-4 M, preferably to 2.5-3 M and solution is conditioned at 20-40°C up to step-like increasing of redox potential (namely to +0.84-+0.87 V), measured using silver chloride reference electrode. In another embodiment of the invention in nitric acid solution containing mixture of plutonium with different valence, namely Pu(VI), Pu(IV), and Pu(III) nitric acid concentration is adjusted to 2-4 M, hydroxylamine is introduced and solution is conditioned at 20-40°C up to step-like increasing of redox potential (namely to +0.84-+0.87 V), measured using silver chloride reference electrode.

EFFECT: accelerated method for chemical tetravalent plutonium stabilization; decreased process step number, reduced heat consumption, and decreased radioactive gases and aerosol release.

4 cl, 6 ex, 3 dwg