Computational modeling and verification for hexcan wall failure under simulated core disruptive accident condition

This paper describes the improvements and verification of computational mod eling for hexcan wall failures assumed to occur under core disruptive accid ent conditions of fast reactors. A series of out-of-pile experiments named SIMBATH has been analyzed by using the SIMMER-II code. The SIMBATH experime nts used a thermite mixture to simulate fuel. The test geometry of SIMBATH ranged from single pin to 37-pin bundles. In this study, phenomena of hexca n wall failure found in a SIMBATH test were analyzed by SIMMER-II with mode l improvements. Although the original model of SIMMER II did not calculate any hexcan wall failure, several model improvements made it possible to rep roduce the hexcan wall melt-through with respect to the formation of an esc ape path for material movement as observed in the experiment. In this paper the model improvements and their significance are discussed for further mo del development of structure failure under the attack of molten fuel materi als. (C) 2000 Elsevier Science Ltd. All rights reserved.