Disclosed is nuclear reactor fuel rod for use in a nuclear reactor. The nuclear reactor fuel rod comprises a sleeve defining a longitudinal axis. The sleeve includes a first end portion and a second end portion. The nuclear reactor fuel rod further includes a first end cap mechanically coupled to the first end portion of the sleeve and a second end cap mechanically coupled to the second end portion of the sleeve. The second end cap is configured to slide along the longitudinal axis relative to the sleeve. The nuclear reactor fuel rod further includes a fuel compact located inside of the sleeve between the first end cap and the second end cap.