Behavior of Nuclear Power Plant Containment under Aircraft Crash

In the present study, a real nuclear power plant (NPP) outer containment structure has been considered for a safety check and the model has been simulated by Abaqus/implicit software. The Three Mile Island (TMI) containment structure has been taken into consideration for the analysis. The dimension of containment is 54.5 m height (without dome) and 45 m inner diameter. A step-by-step analysis was carried out to evaluate the stresses on the NPP wall due to aircraft crash with induced fire. At starting, the impact load 90 MN was applied to the NPP structure using force history curve of Boeing 707-320 aircraft and the angle of impact was considered as normal to the target. After impact, the nodal temperatures were applied to the model through heat transfer analysis using jet fuel curves due to fuel burning. Lastly, the impact and heat transfer effect were combined to get thermal stress behavior. The time gap between the impact of plane’s nose and plane’s wing was kept 0.18 s. Heat transfer analysis has been performed after that time because fuel is stored in wings. The most severe region for the effect of fire is upto 10 m height from the foundation because the maximum fuel will flow to the lowermost of structure. The place of impact was assumed at mid-height of cylindrical portion of TMI containment. The concrete damaged plasticity model for concrete material and Johnson–cook model for steel bar has been taken to incorporate the concrete behavior and reinforcement behavior, respectively. For heat transfer and thermal stress analysis, the parameters and properties of the material at different temperatures were taken from Euro-code 2. From the analysis it can be inferred that there was no global damage due to impact, heat as well as thermal stress in the wall, but certain local damage was found on the outside of the wall.