Trial manufacture of sodium loop for material testing

For the purpose of evaluating corrosion and mass transfer of the new alloy for the fuel caldding tubes and ducts for FBRs in the flowing sodium simulating the core, and obtaining the basic data for improving the composition and treatment condition of the alloy based on the result, a sodium loop was constructed for trial. For the purpose of simulating the core as far as possible about the sodium environment and making the effect of the corrosion of 316 stainless steel used as the structural material of the loop as small as possible, temperature, oxygen concentration in sodium, heating method, heating gradient, downstream effect, flow velocity, temperature difference, time and the effect of different metals were examined, and the design policy, especially the use of a directly electrifying main heater, is explained. Then the details of design, manufacture and the result of operation are reported. The operational condition for fuel cladding tube alloys is as follows: temperature 700 deg C, flow velocity 4 m/s, and oxygen concentration in sodium 1 - 2 ppm. (Kako, I.)