Compatibility studies of copper, brass and cupronickel with Hytherm-500 thermofluid

Carbon steel used as a structural material in thermofluid/water heat exchangers in the Fast Breeder Test Reactor (FBTR) got perforated resulting in leakage. To suggest an alternative better corrosion resistant material for these exchangers, corrosion resistance studies of copper based alloy systems in both a s received and pickled conditions were carried out in the thermofluid medium (Hytherm-500) at room temperature (∼298 K), 373 K and 423 K upto 500 h duration. The tested materials, copper, admiralty brass and 70/30 cupronickel were found to have excellent corrosion resistance in both as-received and pickled conditions. In all the cases corrosion rates decreased with increased duration of exposure. All the above materials showed better corrosion resistance in pickled condition compared to that in as-received condition. The relative corrosion resistance of these three alloys was as follows: admiralty brass > cop per > cupronickel. This trend in the corrosion resistance was observed in both as-received and pickled conditions. In general, the corrosion resistance in pickled condition was found to be better than that in as-received condition. (author). 3 refs., 3 figs., 2 tabs