Noble Metal Chemical Addition for Mitigation of Stress Corrosion Cracking: Theoretical Insights and Applications

摘要

Stress corrosion cracking (SCC) has caused significant economic losses and has challenged component integrity in boiling water reactors (BWRs) over the last three decades. A low electrochemical corrosion potential (ECP), which is beneficial for SCC mitigation, can be achieved by neutralising the oxidising species O2 and H2O2. Combined introduction of noble metals and H2 into the reactor feedwater can accomplish this. Soluble noble metal compounds, injected into the reactor feedwater, rapidly undergo thermolysis to yield metallic nanoparticles which deposit on all water wetted surfaces. These particles exhibit a high catalytic activity for the reaction of O2 and H2O2 with H2. This review presents the noble metal chemical addition (NMCA) technology itself but also briefly describes its impact on reactor environment and provides further information on noble metal nanoparticles, with a focus on their structure, formation and catalytic properties. Finally, possible developments of NMCA and alternative SCC mitigation methods are discussed. The paper aims at providing a comprehensive and interdisciplinary but non-exhaustive overview of the subject.