Various applications of neutrinos are currently a subject of widespread discussions. One of the options considered is to use neutrinos to monitor nuclear reactor cores and oversee nonproliferation of fissile materials. IDREAM is a prototype of the detector designed to register antineutrinos from the reactor core using the inverse beta decay. The detector target is 1 ton of liquid scintillator based on gadolinium-doped linear alkyl benzene. The detector was installed at the Kalinin nuclear power plant (Russia) at a distance of ~20 m from the core. IDREAM started taking data in spring 2021. A description of the detector is presented and the results of the measurements of background conditions at the experiment site are discussed.