On structural response of large LMFBR head closures to hypothetical core disruptive accidents

A finite-element model was developed to assess the ability of a pool-type LMFBR head closure to sustain an energetic HCDA. From a conceptual representation of an expanded EBR-II type deck. It was determined that there is a reasonable amount of symmetry in the structure that an initial model would consist of a 120sector. This model accounts for the main structural elements of the closure head: beams, plates, innner ring, in-tank component nozzle and concrete shielding. The mass of the in-tank component was treated as a concentrated mass located at its attachment in the structural members. The ANL-developed SADCAT code was used in this study. The model was used to study the effect of several design variations on the structural response of the deck to an energetic HCDA. Two types of outer boundary conditions were considered to determine the effect on the closure head's displacement and stress levels. In addition to the above study, an analysis was conducted to determine the structural contribution of the concrete shielding. (Auth.)