We present a novel algorithm to calculate radiative energy transfer rates in Discrete Element Method (DEM)-based simulations of mono-disperse spheres. To verify our algorithm we use the Finite Volume Method (FVM) which enables us to picture relevant radiation phenomena in a dense bed of particles. These phenomena include (i) shadowing, (ii) emission and (iii) adsorption by a constant gray medium. After careful verification, we embed our algorithm in LIGGGHTS, a solver for the DEM. A combination of LIGGGHTS and a solver for intra-particle temperature gradients, i.e., ParScale, is then used to quantify the relevance of radiative heat transfer rates in sheared particles beds. Specifically, we evaluate the relative contributions of conductive, convective and radiative thermal fluxes in granular shear flows of frictional inelastic spheres. We find that the radiative flux can be collapsed onto single curve if it is related to an appropriate dimensionless group. Our analysis establishes a rationale on when radiative heat transfer in dense granular flows should be considered or not. Also, our results can be used to close continuum-based granular dynamics model that aim on predicting the particle temperature distribution under extreme temperature scenarios. (C) 2017 Published by Elsevier B.V.