During an unprotected undercooling accident in a liquid-metal fast breeder reactor, the motion and relocation of the molten cladding can be important because of its potentially significant effect on reactivity, blockage formation, and subsequent fuel motion. The present study analyzes the clad relocation problem based on a multichannel film-flow model. The important aspects considered in the analysis are the non-uniform transverse clad-melting pattern and diversions of sodium-vapor flow within a subassembly. It has been shown that the motion of molten clad and subsequent blockage formations can be significantly influenced by this interconnected channel effect. Several sample calculations have been made in order to demonstrate these points.