Contact corrosion measurements on the pair UO2+x and carbon steel 1.0330 in brines and bentonite porewater with respect to direct waste disposal

Contact corrosion between carbon steel and UO2 was studied in the MgCl2 ric h Q-brine, in bentonite porewater and in saturated NaCl solution by use of contact potential and contact current measurements. In all solutions the ca rbon steel dominates the contact potential, so that this potential is near to the rest potential of the carbon steel. Only in solutions without precip itation of iron corrosion products, the presence of metallic iron slightly reduces the UO2 corrosion rate. If iron corrosion products precipitate, the relevant adsorption of the uranium species will be more effective than any direct cathodic corrosion protection. (C) 1999 Elsevier Science B.V. All r ights reserved.