This paper focuses on the numerical characterization of a new sensor for the measurement of highly concentrated radiative heat fluxes, based on an inverse heat transfer method. The sensor will be coupled to the solar furnace that is being installed at the ENEA Portici Research Center. The highly concentrated radiative heat flux incident on the target surface of the sensor is estimated by implementing the inverse heat transfer method based on the Levenberg-Marquardt algorithm, which permits to compute the radiative boundary condition on the exposed surface of the target by measuring the temperature of its hidden bottom surface. Numerical simulations have been carried out to evaluate the sensor sensitivity to the following parameters: the emissivity of the target surface of the sensor; the synchronization error in the temperature recordings; the uncertainty in temperature measurements; the convection heat transfer coefficient; the misalignment between the axis of the target and the axis of the concentrated solar spot; the uncertainty about the values of the thermo-physical properties of the sensor components materials. (C) 2014 Elsevier Ltd. All rights reserved.