The VR-1 training reactor is a zero power pool-type light water reactor. It is located at the Czech Technical University in Prague. Its layout enables simple and comfortable access to the core, easy insertion and removal of experimental devices and samples, and simple and safe manipulation with fuel assemblies. The reactor consists of two vessels placed in a shielding made of barytic concrete. The H01 vessel contains the reactor core; the H02 vessel serves for manipulations with fuel assemblies and for temporary storage of the fuel. The core is composed of IRT-4M tubular fuel assemblies with the enrichment in U-235 of almost 20 %. Four-, six-, and eight-tube modifications of the fuel assemblies are available. For neutron moderation as well as for heat removal from the core the light demineralized water is used; it also acts as a neutron reflector and a biological shielding. Due to the low power of the reactor, natural convection is adequate for heat removal from the core. The reactor is operated under the atmospheric pressure and the temperature of ca. 20 °C. The reactor control is provided by 5-7 control rods of UR-70 type; their number depends on the particular core configuration. Detectors for power measurement, as well as experimental samples could be inserted in dry vertical channels. Moreover, radial and tangential channels are available.