b'Discrete element method prediction of the cladding burst opening shape (top) and the internal pressure (bottom) impact on the fuel missing length during FFRD under simulated loss of coolant accident. Top panels show the sensitivity of larger fuel fragments (1.55 mm in size) to the cladding opening shape. In contrast, finer particles (corresponding to higher burnup level) used to produce simulation results in the bottom panel (see the simulation snapshot to the right) exhibits less sensitivity to the opening shape as well as internal pressure (except for the case without cladding rupture). 61'