[en] The KROD2M program complex intended for on-line calculating the physical characteristics of the high-temperature gas cooled reactor cores with various arrangements is described. The neutron-physical reactor calculation is performed in the two-group diffusion approximation by the finite-difference method in plane configuration. The reactor is subdivided into a number of zones differing from each other by dimensions and properties. The zones containing burnable (i. e. changing their properties in the process of reactor operation) and unburnable materials are considered. Calculation of coolant, graphite and fuel temperatures are performed by means of the KROD2M complex for slug and spherical fuel elements. The calculation of gaseous fission product release into the coolant and the fuel component of electric power generation cost is provided in the KROD2M complex