Dissolution of synthetic U-DBP and corrosion of stainless steel by dissolution schemes

In spent fuel reprocessing, UO 2 (DBP) 2 (U-DBP) can be deposited in stainless steel equipment. U-DBP must be removed by dissolution and the process must not cause corrosion to stainless steel. This study was conducted to find the best scheme for dissolution. U-DBP was manufactured by the titrimetric sedimentation method. The effects of different factors on the dissolution of U-DBP were investigated. For example, solid-liquid ratio, hydrazine carbonate solutions with different mass components, mixed solutions containing different concentrations of H 2 O 2 , and different carbonates. The results indicated that U-DBP does not have a regular crystal morphology. With the increase of the solid-liquid ratio and the mass fraction of hydrazine carbonate, the concentration of U(VI) at the dissolution equilibrium increases gradually. The addition of H 2 O 2 has a great promotion effect on the dissolution. However, when the concentration of H 2 O 2 is greater than 0.5 M, the dissolution solution may have an erosive effect on the stainless steel. (NH 4 ) 2 CO 3 can increase the dissolution capacity of dissolved U-DBP, but it may also accelerate the corrosion of stainless steel.