  From the discovery of the neutrino to the precision neutrino oscillation
measurements in KamLAND, nuclear reactors have proven to be an important source
of antineutrinos. As their power and our knowledge of neutrino physics has
increased, more sensitive measurements have become possible. The next
generation of reactor antineutrino experiments require more detailed
simulations of the reactor core. Many of the reactor simulation codes are
proprietary which makes detailed studies difficult. Here we present the results
of the open source DRAGON code and compare it to other industry standards for
reactor modeling. We use published data from the Takahama reactor to determine
the quality of the simulations. The propagation of the uncertainty to the
antineutrino flux is also discussed.
