Electrochemical Potentials of Stainless Steel and Platinum in K-Reactor Moderator.

摘要

Most of the cracks observed in the 304 stainless steel of the Savannah River Plant (SRP) reactors have been due to Intergranular Stress Corrosion Cracking (IGSCC). The environment of the stainless steel (i.e., the reactor moderator) is a contributing cause of IGSCC, in combination with stress and sensitization of the steel. The electrochemical potential (ECP) of stainless steel in the moderator provides an indication of the tendency for IGSCC to occur. Laboratory work under boiling water reactor conditions has indicated that lowering the potential of the stainless steel sufficiently would stop IGSCC. Tests in Dresden-2 have shown that injection of hydrogen gas to scavenge oxygen, termed hydrogen water chemistry, lowered the stainless steel potential and stopped both IGSCC initiation and growth. for these reasons the decision was made to measure stainless steel potentials in a SRP reactor. The purpose of this report is to describe the results of more than a year of online measurements of ECP's of stainless steel and platinum electrodes in K-Reactor moderator. 19 refs., 8 figs., 3 tabs. (ERA citation 13:053840)