Cyclic Polarization Behavior of Low Carbon Steel above Simulated High Level Radioactive Waste

Corrosion in the vapor space and at the liquid/air interface of the Department of Energy (DOE) high level waste (HLW) tanks have emerged as potentially active corrosion mechanisms. Controls on the solution chemistry are in place to preclude the initiation and propagation of further nitrate induced pitting and stress corrosion cracking. However, recent experience has shown that steel not in contact with the bulk waste solution but exposed to the vapor space above the bulk waste and the liquid/air interface may be vulnerable to pitting or stress corrosion cracking. Experimentation was performed to determine the cyclic polarization behavior of ASTM A537 low carbon steel, the materials of construction of the tanks, in the vapor space above simulated waste solution. The results suggest steel in the vapor space is protected provided the bulk solution issufficiently inhibited