[en] A parametric study of the containment response of the Grand Gulf plant, a Mark III BWR, has been conducted using the Contain code. The response to extensive debris dispersal following reactor pressure vessel failure at high pressure is examined for a short period after vessel failure, for plant conditions corresponding to a short-term station blackout scenario with water on the floor of the drywell. The discussion of results from this study focuses on the peak drywell-wetwell pressure difference, the peak pedestal pressure, and the potential for drywell flooding after debris dispersal