  For reactor antineutrino experiments, a thorough understanding of the fuel
composition and isotopic evolution is of paramount importance for the
extraction of $\theta_{13}$. To accomplish these goals, we employ the
deterministic lattice code DRAGON, and analyze the instantaneous antineutrino
rate from the San Onofre Nuclear Generating Station (SONGS) Unit 2 reactor in
California. DRAGON's ability to predict the rate for two consecutive fuel
cycles is examined.
