A computational program, based on a diffusion surface deposition of oxygen, has been developed and applied to the calculation of a mesh-packed cold trap. The results were compared with experimental data for a forced-life test that was carried out by internal introduction of sodium peroxide into the sodium loop. Good agreement is obtained for calculations and experimental data in the pressure drop through the cold trap, the trapping efficiency and capacity, and the oxygen deposit distribution in the mesh packing. From this agreement, we conclude that deposition phenomena of oxygen in the mesh-packed cold trap should be treated as diffusion surface deposition under normal operating conditions.