Effects of metal ion concentration on deposition chemistry of Corrosion Related Unidentified Deposits in PWR fuel cladding

• Published in: Corrosion science 2024-08, Vol.236, p.112268, Article 112268
• Main Authors: Lee, Yunju, Ham, Junhyuk, Yoo, Seung Chang, Song, Inyoung, Kim, Ji Hyun
• Format: Article
• Language: English
• Subjects: CRUD; Fuel cladding; Metal ion concentration; Thermal conductivity
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2024.112268

An experimental facility was set up to investigate the effect of metal ion concentration on the formation of CRUD on fuel cladding in simulated pressurized water reactor primary water. The structural and chemical characteristics of the specimens were examined and it was found that the thickness of the CRUD increased with the metal ion concentration. At lower concentrations, a primitive CRUD chimney structures were observed, while higher concentrations led to more developed ones. Chemical analysis indicated more Ni oxide deposition at lower concentrations. Despite thicker CRUD at higher concentrations, enhanced chimney structures improved thermal conductivity by promoting heat transfer through wick boiling behavior. •Structural and chemical changes were observed under high metal ion concentrations.•Only thickness changes were observed in low metal ion concentration conditions.•Formation of NiO and NiFe2O4 depends on metal ion concentration.•Thermal conductivity of CRUD depends on structure and composition.•Proposed chimney structure actuated Wick boiling, promoting heat transfer in CRUD.