We present results from radiation transport calculations for plasma conditions that are expected for the buffer gases of high-gain inertial confinement fusion (ICF) target chambers. In our calculations, the plasmas are not assumed to be in local thermodynamic equilibrium (LTE). The state of the plasmas is obtained by solving multilevel atomic rate equations self-consistently with the radiation field. Radiation is transported using an escape probability model. Atomic physics data is generated using a combination of Hartree-Fock, distorted wave, and semi-classical impact parameter models. Our results show that the self-attenuation of line radiation results in a significant reduction in the radiation flux at the target chamber first wall. We compare our results with those from other calculations and find that the heat fluxes at the first wall are significantly lower than previously predicted by multigroup radiation diffusion models. The lower heat fluxes suggest that thermal conduction within the first wall can act to keep temperatures near the surface of the wall much lower than previously thought, thus reducing problems associated with thermal stresses and vaporization. We discuss the ramifications of our results for the SIRIUS-T ICF reactor.