STRUCTURAL ANALYSIS OF NUCLEAR CONTAINMENT SUBJECTED TO AIRCRAFT CRASH

Abstract

Nuclear containment is a reinforced concrete vessel that encloses a nuclear reactor. It is designed to withstand minor explosions in the core and to keep radio nuclides from escaping into the environment, and to make them safe against terrorist attack. After the September 11, 2001 jet aircraft crash on World Trade Center (WTC), the safety and reliability study of nuclear containments against any similar event has become very significant. This is due to the fact that the consequences related to the failure of a nuclear containment are much more serious than consequences of WTC failure. The failure of nuclear containment may cause sudden release of radioactive, materials and radiations over a large area that may result in a sudden and long-term disaster to human life and all that on which human life sustains. The 1986 failure of Chernobyl nuclear power station is living witness of this type of disaster. Chernobyl rendered more than 1000 square miles unsafe for human life for more than 100 years. The nuclear containment structure provides a leak tight barrier to the radiation and should be designed to withstand impact of missile/ aircraft etc. In order to make an appropriate design of a containment structure, it is imperative to understand its behavior against impact loading. In this study, response of a nuclear containment outer structure against the impact of Boeing 707-320 and Boeing 747-400 Aircraft models is carried out by numerical simulation using ABAQUS/ Explicit 6.10 package. Here the target as well as the projectile both is deformable, the analysis was performed by coupling the problem i.e. modeling of Aircraft and containment done separately. The study is carried out in steps. First a fall different aircrafts Boeing 707-320 and Boeing 747-400 modeled on ABAQUS are impacted towardsl rigid plate and reaction curve for rigid target are obtained and these curves are compared with previous analytical results available and then in second step aircrafts are impacted towards deformable plate that is RCC wall, in this step both aircraft( projectile) and plate i.e. target are deformable , and reaction and stresses are obtained and in the third stage reaction curve obtained from rigid target and reaction obtained from deformable target are compared and in last stage modeled aircraft are impacted towards deformable BWR Mark III TYPE outer containment wall and response are noted. iv Concrete damage plasticity model was used for simulating the behavior of the concrete whereas Johnson cook damage plasticity model for ductile material was used for the reinforcing steel. A strain rate dependent data was used for depicting material parameters for concrete. A 3D continuum element with reduced integration was used for concrete and 3D truss element was used for the steel reinforcement. A 3D deformable shell elements were taken for aircrafts body.