Experiments were conducted to determine the behavior of stationary gas bubbles in narrow liquid-filled gaps. The work was carried out to help answer the question of how fission gas bubbles may behave in the sodium bond of oxide and carbide fueled rods. The hydraulic data obtained with uncracked pellets indicate that stagnant bubbles may exist even when the simulated fuel rod was vibrated. These stagnant bubbles are large enough to cause calculated hot spots in the bond. The location under an overhanging ledge formed by axial eccentric pellets was a common place for bubbles to stagnate. Possible differences between the actual fuel-rod behavior in the reactor and the test conditions may be caused by heating effects which influence bubble motion, cracked pellets which prevent accumulation of fission gas in the bonding, and the release of significant amounts of fission gas only when the reactor is shut down. Equations are presented for the maximum bubble size, and the length and width of bubbles stagnated at the lips (overhang) of fuel pellets.