Over 1500 fuel bundles have been irradiated in NPD. Most of this fuel was sheathed with thin, collapsible sheathing. Burnups and residence times have exceeded 10 000 MWd/t Uranium and 850 days, respectively. The deuterium picked up by the Zircaloy-2 sheathing from the heavy-water coolant has not affected fuel performance. Dimensional changes varied from no change to < 0.05% and ≈ 0.5% on element lengths and diameters, respectively. Measured fission-gas release was < 0.1% of that generated. A defected bundle showed little or no deterioration after two and one-half years operation. For NPD, the first operating reactor of the CANDU-PHW type, the fuel performance is fully proven.