Turbulent flow of liquid lead alloy in oxygen-controlled corrosion erosion test facility

The CORELLA (CORrosion Erosion test facility for Liquid Lead Alloy) facility allows corrosion erosion tests in molten lead alloys at controlled oxygen content and temperature under flowing conditions. Its exposure chamber consists of a cylindrical container, partially filled with the liquid metal. An inner rotating cylinder drives the liquid metal flow. The specimens of interest are fixed vertically inside the chamber such that the lead alloy flows around the specimens on both sides. In this numerical study, the turbulent flow of liquid lead–bismuth eutectic is solved for various specimen configurations, filling heights, and rotational speeds of the inner cylinder. Hereby, the deformation of the free liquid surface is taken into account using a rotationally symmetric approximation. Highly turbulent flow is found even for 200 rpm (revolutions per minute), the lowest rotational speed investigated. The velocity of the liquid metal along the specimens’ lateral surfaces reaches values up to 1.5 m/s for a rotational speed of 1200 rpm, the limit of experimentally stable conditions. Due to the sudden flow constrictions and expansions around the specimens, a much higher effect of the flow on corrosion erosion is expected than for simple pipe flow at the same bulk velocity

Corrosion Investigations of Materials in Antimony–Tin and Antimony–Bismuth Alloys for Liquid Metal Batteries

Liquid metal batteries are discussed as stationary electrical energy storage for renewable energies, in order to compensate their fluctuating supply of energy. A liquid metal battery consists of three different liquids, which stay segregated due to density differences and mutual immiscibility. The negative electrode is the low-density liquid metal, and in our case sodium, a medium density molten salt, is the electrolyte and positive electrode is a high-density liquid metal. For the latter, Sb–Sn and Sb–Bi alloys are selected. However, one issue is the compatibility of structural materials with the used liquids. In a first step, the behavior of potential structural materials in Sb3Sn7 and SbBi9 at the temperature of 450 °C up to 750 h was tested. The results showed that the corrosion in SbBi9 was significantly less than in Sb3Sn7 and the most promising materials were molybdenum meta and Max-phase coatings

Influence of composition and heating schedules on compatibility of FeCrAl alloys with high-temperature steam

FeCrAl alloys are proposed and being intensively investigated as alternative accident tolerant fuel (ATF) cladding for nuclear fission application. Herein, the influence of major alloy elements (Cr and Al), reactive element effect and heating schedules on the oxidation behavior of FeCrAl alloys in steam up to 1500{\deg}C was examined. In case of transient ramp tests, catastrophic oxidation, i.e. rapid and complete consumption of the alloy, occurred during temperature ramp up to above 1200{\deg}C for specific alloys. The maximum compatible temperature of FeCrAl alloys in steam increases with raising Cr and Al content, decreasing heating rates during ramp period and doping of yttrium. Isothermal oxidation resulted in catastrophic oxidation at 1400{\deg}C for all examined alloys. However, formation of a protective alumina scale at 1500{\deg}C was ascertained despite partial melting. The occurrence of catastrophic oxidation seems to be controlled by dynamic competitive mechanisms between mass transfer of Al from the substrate and transport of oxidizing gas through the scale both toward the metal/oxide scale interface.Comment: Submitted to Journal of nuclear materials, accepted recentl