Long-term durability test of acid recovery evaporators made of Ti-5% Ta alloy and zirconium

Mock-ups of acid recovery evaporators which are made of Ti-5%Ta alloy and Z r were tested under non-radioactive condition for 40,000h to solve the corr osion problem in the reprocessing field. A long-term durability of both eva porators was demonstrated by results of operation data, evaporation perform ance, and corrosion resistance. With regards to corrosion resistance, cracks and local corrosion such as pi tting and intergranular attack were not observed on both evaporators after the test, and a corrosion of weld was not selective. The average corrosion rates at measuring points were less than 0.1 mm/yr respectively, however, t hickness of the Ti-5%Ta alloy evaporator was slightly reduced in vapor phas e region. In addition, the destructive inspection showed that the mechanica l properties of both materials were not degraded during the test. From an engineering perspective, an excellent durability of Ti-5%Ta alloy a nd Zr evaporators under high oxidative environment was successfully demonst rated through this mock-up test.