Dissolution of contaminant Zr-DBP and corrosion of stainless steel by dissolved solution

In the nuclear spent fuel reprocessing, zirconium dibutyl phosphate (Zr-DBP) is deposited on the surface of stainless steel equipment, making spent fuel reprocessing difficult. Therefore, in this study, hydrazine carbonate ((N 2 H 5 ) 2 CO 3 ) was used to dissolve Zr-DBP. The effects of solid–liquid ratio, different mass fractions of (N 2 H 5 ) 2 CO 3 solutions, and (N 2 H 5 ) 2 CO 3 solutions containing different concentrations of hydrogen peroxide (H 2 O 2 ) on the dissolution of Zr-DBP were investigated. The corrosion rates of different dissolution solutions on stainless steel were also investigated. When the mass fraction of (N 2 H 5 ) 2 CO 3 in solution was increased from 1 % to 20 %, the concentration of Zr(IV) at dissolution equilibrium increased from 1.05 g/L to 1.61 g/L, respectively. When the dissolution temperature was kept in the range of 25 °C to 65 °C, the increasing temperature promoted the dissolution of Zr-DBP. The presence of H 2 O 2 induced the production of the white precipitates zirconium hydroxide (Zr(OH) 4 ). In addition, the corrosion rate of stainless steel gradually increased from 0.00153 mm/a to 0.0138 mm/a when the concentration of H 2 O 2 in the (N 2 H 5 ) 2 CO 3 solution was increased from 0 M to 1.5 M. The dissolution ability of Zr-DBP in different carbonate solutions was (N 2 H 5 ) 2 CO 3  ≥ ammonium carbonate ((NH 4 ) 2 CO 3 ) > sodium carbonate (Na 2 CO 3 ) ≥ potassium carbonate (K 2 CO 3 ).