Burst Test of Zirconium Alloy at High Temperature under Internal Pressure

It is important to maintain the integrity of zirconium alloy fuel cladding because that is a barrier against radioactive fission products. Many researchers investigated the behavior of cladding under loss-of coolant accident (LOCA). When LOCA occurs, cladding temperature rise rapidly and primary system pressure drop to atmospheric range. However, the internal pressure of cladding is preserved ∼MPa because of the generation of fission products and the swelling of fuel pellets. Therefore, the difference of pressure can induce the local ballooning and burst. Some investigators conducted ballooning-burst tests. F. J. Erbacher and S. Leistikow researched the oxidation and embrittlement behavior of zircaloy cladding by simulating a LOCA. F. Erbacher et al. studied single rod and bundle tests in the fuel rod simulator. P. Hofmann investigated the influence of iodine on the burst test, and Jun Hwan Kim et al. studied the deformation of Zircaloy-4(Zry-4) under isothermal and transient-heating tests. Only Zry-4 was used in their study, except for an Nb-added alloy. Also most of the investigations were tested under transient temperatures to simulate a LOCA. Therefore, fundamental data of the ballooning-burst on the uniform temperature is insufficient. In this study, the ballooning-burst behavior of Zry-4 and an Nb-added alloy was studied and fundamental data was produced