[en] The effects of transient history on fuel motion driven by fission gas have been investigated in a series of direct-electrical-heating tests on quartz-clad irradiated fuel. Variations in the slow, Stage-I portion of the transient thermal history resulted in pronounced differences in fuel behavior during the subsequent, more rapid, Stage-II portion. Analysis of transient fission-gas behavior, considering both the timing of gas release to grain boundaries and the non-equilibrium character of grain-boundary gas bubbles, provides a coherent picture of the role of fission gas in the observed fuel failure. The results indicate the conditions under which fission gas may efficiently drive expulsion of molten fuel through cracks, as well as conditions under which gross radial swelling of the fuel may be expected. These predictions are compatible with the observed nature of fuel failure