FINITE ELEMENT ANALYSIS OF BWR AND PHWR CONTAINMENT STRUCTURES SUBJECTED TO AIRCRAFT CRASH

Abstract

Nuclear power plants (NPP) play an important role to drive economy with clean energy. A scenario would be an accidental or deliberate aircraft impact on NPP. The procedure involving load-time curve has got limitations, hence missile interaction method was employed by considering the fact of increased computational capacity. A qualitative and quantitative study was made on PHWR containment subjected to impact by Boeing 707-320 aircraft by utilizing explicit dynamic code available in ANSYS FEM simulation software with solver AUTODYN. Reaction time study has been performed to verify the numerical model of aircraft considering aluminium alloy as isotropic Bi-linear behaviour with strain hardening and equivalent plastic strain as failure criteria. The numerical model of RCC containment has modelled as a discrete model with solid 8-nodded elements for concrete and 2 nodded truss elements for steel rebar. RHT model has been used for concrete which has the ability to predict the dynamic strength and damage criteria involving equivalent plastic strain. Johnson-cook model which predicts the dynamic strength of ductile material has been employed for steel rebar. The present study aims to generate a numerical model of NPP which can have highest level of reliability. A parametric study was conducted to understand residual velocity, scabbing area and perforation depth caused by aircraft impact by varying the reinforcement ratio. Results showed that as the percentage of reinforcement increased, residual velocity and penetration depth decreased and scabbing area had little influence.