Corrosion behavior of GH3535 alloy in molten LiF–BeF2 salt

Corrosion Testing Trade Study on Testing Methods in Molten Salts

“…Mo oxidation (MoO2) has also been reported by Yang et al (2022) during exposure of GH3535 (Hastelloy N) in FLiBe salt with NiF2 impurities and O2 leakage, both at the HL and CL of a TCL setup operating at 660 ºC and 561 ºC, respectively. Addition of Be metal can act as a "scavenger" of impurities, reducing the overall corrosion of the alloy (Yang et al 2022;Ignat'ev et al 2006).…”

“…For the former case, the summation of H2O+O2 impurities was less than 100 ppm, while for the latter case it was over 500 ppm, which led generally to higher measured corrosion rates and a uniform extensive oxidation, which even included Ni and Mo (Koger 1973). Mo oxidation (MoO2) has also been reported by Yang et al (2022) during exposure of GH3535 (Hastelloy N) in FLiBe salt with NiF2 impurities and O2 leakage, both at the HL and CL of a TCL setup operating at 660 ºC and 561 ºC, respectively. Addition of Be metal can act as a "scavenger" of impurities, reducing the overall corrosion of the alloy (Yang et al 2022;Ignat'ev et al 2006).…”

Influence of SiC content in B4C–nSiC composites corrosion in molten FLiNaK salt at 800°C

“…Dai et al 15 . reported that metal ions (Cr, Fe) on the surface of 800H alloy (major elements: Ni, Cr, Fe, Mn, Si, and C) underwent a redox reaction with FLiNaK molten salt, resulting in their depletion from the surface of the alloy and the grain boundaries, thus forming a “diffusion path.” Yang et al 16 . indicated that the corrosion of the GH3535 alloy (major elements: Ni, Cr, Mo, Fe, Mn, Si, and C) exposed to molten FLiBe salt resulted from the reaction between oxygen impurities and the components of the salt, as well as metal ions in the alloy, leading to the formation of oxides, such as MoO 2 and BeCr 2 O 4 .…”

“…[12][13][14] Dai et al 15 reported that metal ions (Cr, Fe) on the surface of 800H alloy (major elements: Ni, Cr, Fe, Mn, Si, and C) underwent a redox reaction with FLiNaK molten salt, resulting in their depletion from the surface of the alloy and the grain boundaries, thus forming a "diffusion path." Yang et al 16 indicated that the corrosion of the GH3535 alloy (major elements: Ni, Cr, Mo, Fe, Mn, Si, and C) exposed to molten FLiBe salt resulted from the reaction between oxygen impurities and the components of the salt, as well as metal ions in the alloy, leading to the formation of oxides, such as MoO 2 and BeCr 2 O 4 . The chemical constituents of GH3535 alloy and weldment (matching filler metal) were thermodynamically prone to the formation of fluorides, which was demonstrated by Muránsky et al 17 and Danon et al 18 However, galvanic coupling corrosion occurred in the GH3535 alloy due to the presence of large M 6 C carbides in its microstructure.…”

Radionuclide tracing based in situ corrosion and mass transport monitoring of 316L stainless steel in a molten salt closed loop

“…Structural material corrosion testing in flowing conditions dates back to the Aircraft Reactor Experiment, followed by the Molten Salt Reactor Experiment at Oak Ridge National Laboratory (ORNL) in the 1950s and 1960s [15][16][17] where corrosion studies were mainly carried out in closed natural circulation loops 13,14,18,19 . In many of these studies, samples were suspended in various sections of molten salt loops [20][21][22] followed by post-corrosion examination of the samples. Small-scale natural circulation loops, or microloops, were recently developed by TerraPower, where the loop pipe itself served as the corrosion testing sample 23 .…”