Xenon Oscillations in a VVÉR-1000 Core

Xenon oscillations – periodic redistribution of the power over the core volume – can occur in a VVÉR-1000 core because of the large size of this core. The xenon oscillations can be conventionally divided into axial, radial, diametral, and azimuthal. In the present paper, methods are described for initiating the oscillations and the results of experimental investigations of the characteristics of free axial, diametral, and azimuthal xenon oscillations in the reactor core in the No. 1 unit of the Rostov nuclear power plant are presented; the experiments were performed at the start of burnup of the first (head) fuel load, completely consisting, for the first time, of improved fuel assemblies. Among other things, it is established that the periods of all oscillations investigated are the same. The azimuthal xenon oscillations are most rapidly damped.