  Motivated by relativistic jets observed in active galactic nuclei (AGN), we
simulate outflows of electron-positron pairs strongly coupled with photons from
normal electron-proton plasmas. Using multi-fluid approximation and a Monte
Carlo method of radiative transfer, we obtain spherically symmetric, steady
solutions of radiation and pair outflows for the luminosity $L \leq 10^{47}$
erg ${\rm s^{-1}}$. For microphysics, Coulomb scattering, Compton scattering,
bremsstrahlung, electron-positron pair annihilation and creation are taken into
account. Although a significant amount of pairs outflow by powerful radiative
force with a mildly relativistic velocity, the temperature is not high enough
to avoid pair annihilation before the fireball becomes optically thin to
scattering. Several caveats in the simulations are also discussed.
