[en] It has been postulated that the use of annular fuel provides an inherent safety shutdown mechanism during hypothetical LMFBR accidents by providing a pathway for molten fuel to be ejected from the active core region to the fission gas plenum. Previous work evaluating internal fuel motion for whole-core, transient overpower accident cases has been unable to demonstrate the viability of the mechanism for ramp rate cases of $3/s with 3$ total reactivity insertion and below. Continued work reported here has identified an axial blanket internal hole size design variation which does significantly improve the viability of internal fuel motion to act as an inherent safety shutdown mechanism. The size of axial blanket central hole studied was 0.356 cm diameter (large), double the 0.178 cm diameter (small) used previously. Three combinations of annular axial blankets and fission gas plena have been analyzed with the large size central hole: top annular blanket and plenum, bottom annular blanket and plenum, and both top and bottom (dual) annular blankets and plena. The base case assumed a 3$/s transient overpower (TOP) accident with a $3 reactivity insertion for a 2550 MWt Large Development Plant (LDP) heterogeneous core design. The cases were analyzed using the coupled MELT-IIIB/FUMO-E code