The performance enhancement of containment with fiber reinforcement following a LOCA considering different ambient conditions.

The prestressed concrete containment vessels (PCCVs) will be exposed to the temperature action followed by the internal pressure increasing after a loss of coolant accident (LOCA) with safety system failure. The damage evolution of the PCCV under the effect of thermal-pressure coupling deserves in-depth study. Moreover, different containment external temperatures are seldom considered in previous studies whereas they may further pose a great challenge for the design and safety of containments. Just as important, an attempt is first made in this paper to involve steel fiber in the construction of the containment to observe the performance of the containment with steel fiber strengthening under the effect of thermal-pressure coupling. Therefore, the influence of the possible outside temperature (i.e. −30 °C, −15 °C, 0 °C, 15 °C, and 30 °C) determined from the 5 existing or planned nuclear power plant sites in China on the distribution of temperature field of containment is researched firstly. Then, the damage indices corresponding to the containment are defined to represent the actual damage performance and failure mechanism of the structure. Finally, the comparative damage performance and failure mechanism between conventional and steel fiber reinforced concrete (SFRC) containments taking into account the effect of coupling temperature and internal pressure is detailedly discussed. The results show that the SFRC is more expeditious in restraining radial and vertical displacement of containment under lower external temperatures for subsequent internal pressure. Under the ultimate internal pressure, the SFRC containment has a reduction rate of 5.37% for radial displacement and 35.52% for vertical displacement at an external temperature of −30 °C, while 2.23% and 15.33% at an external temperature of 30 °C, respectively. Furthermore, SFRC containment has better performance under the effect of coupling of temperature and internal pressure compared to conventional containment. For example, at an internal pressure of 1.2 MPa, the damage reduction rate for concrete is 94.18% at an external temperature of −30 °C and 81.37% at 30 °C; for the steel liner, the damage reduction rate is 50.22% at an external temperature of −30 °C and 87.83% at 30 °C. For the containment prestressing tendons, the damage reduction rate is around 60% under ultimate internal pressure. The study can provide important guidance for siting and design of nuclear containments and alternative retrofitting measures for nuclear containments. • The distribution of the containment temperature field under the LOCA is obtained. • New damage assessment parameters for containment are proposed. • Different external temperatures that affect the containment's performance is studied. • The reinforcement effect of steel fibers on the performance of the containment is evaluated. [ABSTRACT FROM AUTHOR]