Anodic and Cathodic Protection Assessment on Chloride Molten Salts for the Next Generation of CSP Plants

Abstract

The prevention of high-temperature corrosion on containment materials plays a critical role, and a corrosion mitigation plan is needed to achieve the target plant lifetime of 30 years. This paper analyzed two mitigation corrosion strategies (anodic and cathodic protection) in a eutectic ternary chloride molten salt, composed by 20.4wt.% KCl + 55.1wt.% MgCl2 + 24.5wt.% NaCl. The corrosion mechanism and corrosion rates were obtained through electrochemical impedance spectroscopy (EIS). Ni base alloys generate a protective scale layer (anodic protection) during 8 hours of immersion with a corrosion rate of 6.34 mm/year (In702) and 3.12 mm/year (HR224). Monitoring corrosion results were confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), obtaining alumina and chromia protective layers.

Angel G. Fernández wants to acknowledge the financial support from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.