[en] The assessment of fuel behaviour during normal operation and in accidents requires a detailed calculation of fuel element temperature distribution. This paper reports the results of three applications of the FEAT computer code to calculate fuel element temperature distribution subjected to load following, partial sheath dryout, and end flux peaking with natural and enriched fuel. During load following operation, the fuel pellet expands and contracts thermally due to the power variation. This results in a non-uniform gap conductance between the pellet and the sheath. The pellet circumferential temperature distribution is evaluated parametrically as a function of element power and non-uniform heat transfer coefficient between the pellet and the sheath. The pellet-sheath gap conductance and element power have a significant effect on the pellet temperature. It is assumed that during a postulated loss of regulation accident some fuel elements will operate in dryout with the attendant reduction in sheath-to-coolant heat transfer. The maximum power level at which there is no fuel centerline melting is calculated. With sheaths in partial dryout the fuel centerline temperature is lower than with full dryout patch wrapped around the circumference of the fuel element. For all operating modes, the heat flux is higher near the ends of the fuel element than at the centre; this is known as end flux peaking. The effect on fuel temperature distribution is calculated for two cases: an element filled with natural uranium and an element filled with slightly enriched uranium The calculations show that the temperature peak to average temperatures is much larger for enriched fuel than for natural fuel. (Author) 5 refs., 6 figs., tab