Sensitivity analysis for heat transfer in a fin of a nuclear fuel rod

Abstract

To carry out sensitivity analysis on a finned surface, the differential perturbative method is applied in a heat conduction problem within a thermal system, made up of a one-dimensional circumferential fin on a nuclear fuel element. The model is described by the temperature distribution equation and the further specific boundary conditions. The adjoint system is used to determine the sensitivity coefficients to the case of interest. Both, the direct model and the perturbative formalism resultant equations are solved. The heat flow rate at a specific point of the fin and the average temperature excess were the functional responses studied. The half thickness, the thermal conductivity, the heat transfer coefficients and the heat flow at the base of the fin were the parameters of interest to the sensitivity analysis. The results obtained through the perturbative method and the direct variation presented, in a general form and within acceptable physical limits, good concordance and excellent representativeness to the analyzed cases. One evidences that the differential formalism is an important tool to the sensitivity analysis, and it validates the application of the methodology in heat transmission problems on extended surfaces. The method proves to be useful and efficient while elaborating thermal engineering projects.