  JUNO is a massive liquid scintillator detector with a primary scientific goal
of determining the neutrino mass ordering by studying the oscillated
anti-neutrino flux coming from two nuclear power plants at 53 km distance. The
expected signal anti-neutrino interaction rate is only 60 counts per day,
therefore a careful control of the background sources due to radioactivity is
critical. In particular, natural radioactivity present in all materials and in
the environment represents a serious issue that could impair the sensitivity of
the experiment if appropriate countermeasures were not foreseen. In this paper
we discuss the background reduction strategies undertaken by the JUNO
collaboration to reduce at minimum the impact of natural radioactivity. We
describe our efforts for an optimized experimental design, a careful material
screening and accurate detector production handling, and a constant control of
the expected results through a meticulous Monte Carlo simulation program. We
show that all these actions should allow us to keep the background count rate
safely below the target value of 10 Hz in the default fiducial volume, above an
energy threshold of 0.7 MeV.
