  Antineutrinos produced at nuclear reactors constitute a severe source of
background for the detection of geoneutrinos, which bring to the Earth's
surface information about natural radioactivity in the whole planet. In this
framework we provide a reference worldwide model for antineutrinos from
reactors, in view of reactors operational records yearly published by the
International Atomic Energy Agency (IAEA). We evaluate the expected signal from
commercial reactors for ongoing (KamLAND and Borexino), planned (SNO+) and
proposed (Juno, RENO-50, LENA and Hanohano) experimental sites. Uncertainties
related to reactor antineutrino production, propagation and detection processes
are estimated using a Monte Carlo based approach, which provides an overall
site dependent uncertainty on the signal in the geoneutrino energy window on
the order of 3%.
  We also implement the off-equilibrium correction to the reference reactor
spectra associated with the long-lived isotopes and we estimate a 2.4% increase
of the unoscillated event rate in the geoneutrino energy window due to the
storage of spent nuclear fuels in the cooling pools. We predict that the
research reactors contribute to less than 0.2% to the commercial reactor signal
in the investigated 14 sites. We perform a multitemporal analysis of the
expected reactor signal over a time lapse of 10 years using reactor operational
records collected in a comprehensive database published at
www.fe.infn.it/antineutrino.
