Numerical Simulation of Cobalt Absorber Rod Transportation Flask Under Impact Loading and Design of Impact Limiter Cage

A Lead shielded Cobalt absorber rod transportation flask has been designed for transportation of Cobalt absorber rod through public domain as Type B(U) package. As per the IAEA/AERB regulations for safe transport of radioactive materials, the flask should demonstrate compliance to the performance standards for normal and accident conditions of transport. In view of this, the ability of the flask to withstand 9m drop on an unyielding target in most damaging orientation is verified by finite element analysis and design improvement is carried out in the flask. The explicit finite element (FE) code PAM-CRASH is used for the numerical simulation. It is found that the stresses and deformations in flask components do not meet structural integrity criteria. Therefore, an impact limiter cage is conceptualized and series of design modifications in the cage are carried out through numerical simulations to meet the structural integrity requirement under different drop orientations. The cage serves the purpose of an effective impact limiter and meets the structural integrity criteria by limiting overall damage to the flask. The concepts of cage and drop test simulation results are presented in this paper along with comparison of simulation results of flask with cage and without cage.