Fatigue Crack Propagation Behavior of Zirconium in Boiling Nitric Acid Solution

摘要

For long term durability evaluation of the reprocessing facility equipment made of zirconium, the fatigue crack propagation behavior of zirconium in heat affected zone (HAZ), weld metal (DEPO), and base metal (BASE) was investigated. Fatigue crack was propagated in room temperature atmosphere and in the boiling nitric acid solution. The crack propagation behavior of zirconium was evaluated by the measurement of crack propagation rate and the fracture surface analysis. The fatigue crack propagation was accelerated in the boiling nitric acid solution. Moreover the fracture surface caused in the boiling nitric acid solution was fluted one. It was guessed that acceleration factor of the fatigue crack propagation was the stress corrosion cracking (SCC). Crack sensitivity in the boiling nitric acid environment of welded joint (HAZ and DEPO) and BASE was almost the same.