[en] A radiative heat transfer model proposed for the boiling water reactor (BWR) version of the Transient Reactor Analysis Code (TRAC) is described. The model includes radiative heat transfer to the nonequilibrium two-phase fluid, as well as surface-to-surface radiative heat transfer. Radiative properties and geometric view factors are calculated. It is assumed that each surface is a gray surface and that the liquid and vapor are gray fluids. A stand-alone code RADHT is described, and this code was used to examine the effect of the void fraction, liquid droplet diameter, vapor temperature, wall emissivity, and the number of rod groups. The results show that five rod groups (including the channel wall) are sufficient to describe the radiative heat transfer in a BWR bundle. The results also show that radiative heat transfer to the two-phase mixture should be considered in addition to surface-to-surface effects