ICONE15-10524 Development of SCC Mitigation Method in BWR Plant by TiO_2 Technique

Abstract

TiO 2 addition into boiling water reactor (BWR) primary system is being developed as a method to mitigate stress corrosion cracking (SCC) of the BWR structural materials. This technique aims for electrochemical corrosion potential (ECP) decrease of reactor materials by photo-excitation reaction under Cherenkov irradiation. Tests have been conducted in the test loop in both BWR and OECD Halden reactor to investigate the feasibility of the SCC mitigation method with TiO 2 . The test results showed that the ECP of TiO 2 deposited materials was decreased to <-0.3V(vs.SHE) under both UV light irradiation in the BWR reactor water normal water chemistry (NWC) environment and in-core Cherenkov irradiation in the Halden BWR simulation loop under higher dissolved oxygen condition. This TiO 2 technique was confirmed to be feasible as a SCC mitigation method for BWR structural materials.