燃料包壳锆合金的爆破性能

Burst Test Research on Zirconium Alloy for Nuclear Fuel Cladding Tubes

摘要:

文章模拟了燃料包壳用Zr-Nb合金管材在RIA事故工况下的失效行为,研究了温度和升压速率对管材爆破性能的影响。不同温度下快速爆破时的升压速率分别为293K时0.97GPa/s,473K时0.62GPa/s,623K时0.49GPa/s；参考ASTM标准实施的爆破试验在各温度下的升压速率均为0.23MPa/s。结果表明,爆破温度升高,管材爆破强度降低,破口的环向延伸率升高,管材的均匀延伸率受温度影响不明显。所有测试条件下管材均呈鼓包失效,破口沿轴向延伸,升压速率高,破口更宽。温度越高,管材塑性增加,破口长度减小。

Abstract:

To evaluate the mechanical properties and promote a better understanding of failure behavior of the newly developed Zr-Nb cladding tubes during reactivity initiated accidents (RIAs), burst tests were carried out with the biaxial stress state under different pressurization rates at the temperature ranging from 293 to 623 K. The influence of pressurization rate and test temperature was characterized in this test. The pressurization rates were 0.97 GPa/s at 293K, 0.62 GPa/s at 473K, and 0.49 GPa/s at 623K for the fast pressurization test, 0.23 MPs/s for the ASTM burst test. Maximum hoop stress was respectively increased by 10.61, 9.32 and 8.26 % compared to the ASTM burst test at 293K, 473K and 623K. The burst ultimate hoop stresses (UHS) at rupture decreased while the total circumferential elongation (TCE) increased monotonically with the rise of temperature, the uniform circumferential elongation (UCE) was not significantly affect by the test temperature. All the burst tests resulted ductile ballooning failure, cracks initiated and propagated along the axial direction above the maximum hoop stress. A higher pressurization rate resulted shorter but wider crack. As the test temperature raised, the ductility increased and the propagation of the axial crack was suppressed.