The potential for catastrophic fuel damage during beyond-design-basis overpressurization accidents in a boiling water reactor

Beyond-design-basis overpressurization events in a boiling water reactor are studied to determine if they can lead to catastrophic fuel damage, i.e., fuel fragmentation and the rapid disruption of coolable geometry. This is part of a broader study for the U.S. Nuclear Regulatory Commission to question the adequacy of the events previously selected as the design basis, and to determine if any sequences need more analysis in the context of severe accident research. The RELAP5/MOD2 calculations with failures of the reactor trip and recirculation pump trip, as well as safety and relief valve failures, show that no catastrophic fuel damage is expected. This, in combination with the low frequency of occurrence that can be inferred from this paper, results in a recommendation that no further consideration be given to these events at this time