A computational fluid dynamics (CFDs)-assisted scaling methodology is proposed for a TN24P cask (Creer et al., 1987). In the proposed methodology, the height and the number of assemblies were scaled down based, respectively, on the integral scaling criteria by Ishii and Kataoka (1984) for a natural-circulation loop under single phase flow and on the concept of an insulator on the surface of the basket. The controlling scaling parameters for the TN24P cask (the scaling ratio of the heat flux, 1.6; the thickness and conductivity of the insulator, 9 mm and 0.05 W/m K, respectively) were estimated by comparing the results of a TN24P cask experiment (Creer et al., 1987) with those of a CFD simulation of a TN24P cask scaled down, using Fluent code. Based on the proposed scaling methodology and its scaling parameters. a thermal-hydraulic experiment with a half-height single assembly was carried out. The experiment was analyzed in comparison with a CFD simulation to validate the proposed CFD models in Fluent code. The results showed good agreement for the peak cladding temperature (215 degrees C from the experiment, 212 degrees C from the CFD). It is regarded that the proposed scaling methodology was reasonably validated as maintaining the similarity of the temperature gradient and the peak cladding temperature. (c) 2010 Elsevier B.V. All rights reserved.