Significance and examples on field measurement of electrochemical corrosion potential at nuclear power plants

Improvement of water chemistry environment would be promising as one of the mitigative measures for degradation of structural material in nuclear power plants such as stress corrosion cracking (SCC), flow accelerated corrosion (FAC), and so on. It seems not fully reliable, however, when the effectiveness of water chemistry improvement is demonstrated only by material tests in laboratories. It is very important, therefore, to monitor the major environmental parameters such as electrochemical corrosion potential (ECP) in real plants. Significance of on-site ECP measurement is discussed showing experiences in commercial nuclear power plants. (author)