  Spent nuclear fuel (SNF) antineutrino flux is an important source of
uncertainties for a reactor neutrino flux prediction. However, if one want to
determine the contribution of spent fuel, many data are needed, such as the
amount of spent fuel in the pool, the time after discharged from the reactor
core, the burnup of each assembly, and the antineutrino spectrum of the
isotopes in the spend fuel. A method to calculate the contribution of SNF is
proposed in this study. In this method, reactor simulation code verified by
experiment have been used to simulate the fuel depletion by taking into account
more than 2000 isotopes and fission products, the quantity of SNF in each six
spend fuel pool, and the antineutrino spectrum of SNF varying with time after
SNF discharged from core. Results show that the contribution of SNF to the
total antineutrino flux is about 0.26%~0.34%, and the shutdown impact is about
20%. The SNF spectrum would distort the softer part of antineutrino spectra,
and the maximum contribution from SNF is about 3.0%, but there is 18\%
difference between line evaluate method and under evaluate method. In addition,
non-equilibrium effects are also discussed, and the results are compatible with
theirs considering the uncertainties.
