Kinetics experiments on coupled cores in the ZED-2 reactor

A series of space-time kinetics experiments has been performed in the ZED-2 reactor. The main purpose of the experiments was to provide a set of data with which to test the adequacy of spatial kinetics codes and models used to describe the behaviour of large, heavy-water-moderated power reactors. The experiments were designed to minimize excitation of the fundamental mode. A pseudo-random binary sequence was used to control the movement of two absorbers located symmetrically, one in each half of the reactor, and moving vertically in opposite directions. To increase the reactor's susceptibility to flux tilt a split-core configuration was used. The reactor response was measured using three neutron detectors. A comparison of the frequency responses derived experimentally with a point-reactor model and other, more exact models is presented. Because of the limited number of experiments done it was not possible to obtain the wide range of results needed to thoroughly check a kinetics code. Additional experiments are planned, using an improved measurement technique, to yield additional information on the kinetic behaviour of large reactor systems. (author)