Effect of the [U(IV)/U(III)] ratio of fuel salt on selective chromium corrosion and tellurium intergranular cracking (IGC) of Hastelloy N alloy in the LiF-BeF2-UF4 salt mixture was investigated. The chromium corrosion of Hastelloy N alloy is caused by the oxidation of chromium on the alloy surface by reaction with UF4. | Effect of the U IV U III ratio on selective chromium corrosion and tellurium intergranular cracking of Hastelloy N alloy in the fuel LiF-BeF2-UF4 salt EPJ Nuclear Sci. Technol. 6 4 2020 Nuclear Sciences A. Surenkov et al. published by EDP Sciences 2020 amp Technologies https epjn 2019033 Available online at https REGULAR ARTICLE Effect of the U IV U III ratio on selective chromium corrosion and tellurium intergranular cracking of Hastelloy N alloy in the fuel LiF-BeF2-UF4 salt Aleksandr Surenkov1 Victor Ignatiev1 Mikhail Presnyakov1 Jianqiang Wang2 Zhijun Li2 Xinmei Yang2 and Zhimin Dai2 1 National Research Centre Kurchatov Institute NRC KI Kurchatov sq. 1 123182 Moscow Russia 2 Shanghai Institute of Applied Physics SINAP Chinese Academy of Sciences 201800 Shanghai Jiading . China Received 29 January 2019 Received in final form 13 September 2019 Accepted 27 September 2019 Abstract. Effect of the U IV U III ratio of fuel salt on selective chromium corrosion and tellurium intergranular cracking IGC of Hastelloy N alloy in the LiF-BeF2-UF4 salt mixture was investigated. The chromium corrosion of Hastelloy N alloy is caused by the oxidation of chromium on the alloy surface by reaction with UF4. The tellurium IGC of Hastelloy N alloy is caused by the diffusion of tellurium along the grain boundaries with the formation of unstable tellurides with based metals and alloying additives. Results indicate that the selective chromium corrosion and the tellurium IGC of the Hastelloy N alloy in fuel salt can be controlled by the U IV U III ratio. The tellurium IGC of Hastelloy N alloy exposed in fuel LiF-BeF2-UF4 salt can be avoided. For temperatures up to 760 C the selective chromium corrosion can be minimized to the acceptable level when the U IV U III ratio of fuel salt is bellow 30 40. 1 Introduction Two main problems of Hastelloy N requiring further development turned up during the operation of the MSRE. The advanced metallic material for .
