Experimental equipment for fretting corrosion simulation in heavy liquid metals for nuclear applications

Abstract Structural materials development is a key issue for the realization of advanced lead/lead alloy cooled nuclear reactors and accelerator driven systems. One specific challenge for fuel claddings and heat exchanger tubes is the fretting corrosion by flow induced vibrations. In this work, the experimental equipment to investigate fretting corrosion in molten lead/lead alloy is discussed. A dedicated facility was designed and realized to simulate, under reactor relevant conditions, the fretting wear in possible friction contacts. This facility, named FRETHME (FREtting corrosion Test in Heavy liquid MEtals), simulates fretting through the contact between counter specimens under load and oscillating specimens. The main affecting parameters like amplitude, frequency, applied load and friction force are controlled and monitored during the tests. Temperature and oxygen content of the lead/lead alloy are determined by apposite heating system and gas supply. The results of the first fretting tests conducted in air and molten lead, dedicated to demonstrate the feasibility of the fretting corrosion apparatus and to confirm the wear mechanism, are reported. Due to the lubricating action, in molten lead at 450 °C a smaller fretting damage than in controlled atmosphere (10 −12  ppm of oxygen) at 450 °C and in air at room temperature was noticed.