  The RED-100 experiment with a liquid xenon target was carried out at Kalinin
Nuclear Power Plant. The goal of the experiment is the detection and study of
the coherent elastic neutrino nucleus scattering process (CE$\nu$NS) for the
low-energy antineutrinos in close vicinity to a reactor core. A good
understanding of the external radioactive background is needed to achieve this
goal. This paper describes the external background conditions for the RED-100
experiment at Kalinin Nuclear Power Plant.
