  The CERN FCC-ee top-up booster synchrotron will accelerate electrons and
positrons from an injection energy of 20 GeV up to an extraction energy between
45.6 GeV and 182.5 GeV depending on the operation mode. These accelerated beams
will be used for the initial filling of the high-luminosity FCC-ee collider and
for keeping the beam current constant over time using continuous top-up
injection. Due to the high-intensities of the circulating beams, collective
effects may represent a limitation in the top-up booster. In this work we
present a first evaluation of the impedance model and the effects on beam
dynamics. Methods to mitigate possible instabilities will be also discussed.
