核电厂严重事故下预应力混凝土安全壳极限承载力分析

安全壳作为反应堆和环境之间的实体屏障,需要在各种事故工况下能够防止或缓解放射性物质向环境的释放,其中严重事故下的极限承载能力是衡量安全壳完整性的重要指标。通过构建预应力混凝土安全壳结构模型,分别考虑材料本构模型、预应力损失和严重事故下的温度压力效应,对不同内压载荷下安全壳的结构特性进行非线性有限元分析计算,并结合失效准则,研究安全壳极限承载力的确定方法。结果表明：安全壳极限承载力由设备闸门附近区域的应力水平控制,当内压增大到0.96MPa时,安全壳筒壁混凝土全截面达到抗拉强度,大部分混凝土退出工作,当内压增大到1.21MPa时,设备闸门附近的钢衬里出现一定的屈服,安全壳达到承载力极限状态。

The analysis of ultimate bearing capacity of prestressed concrete containment under severe accident in nuclear power plant

As the solid barrier between the reactor and the environment, the containment needs to be able to prevent or alleviate the release of radioactive materials to the environment under various accident conditions. The ultimate bearing capacity under serious accidents is an important indicator of the integrity of the containment. According to the structural model of prestressed concrete containment, the nonlinear finite element analysis and calculation of the structural characteristics of the containment under different internal pressure loads are carried out considering the material constitutive model, the prestress loss and the temperature and pressure effect under serious accidents, respectively. Combined with the failure criterion, the ultimate bearing capacity of the containment is analyzed. The results show that the ultimate bearing capacity of the containment is controlled by the area near the equipment gate. When the internal pressure increases to 0.96 MPa, the full section of the concrete wall of the containment reaches the tensile strength, and most of the concrete exits from work. When the internal pressure increases to 1.21 MPa, the steel lining near the equipment gate yields to a certain extent, and the containment reaches the ultimate bearing capacity.