Measurement and calculation of neutron flux deformation during rod drop transient at the VR-1 reactor

The rod drop experiment was performed at the VR-1 reactor to test the detection system and collect data that describe the development of neutron flux during rod drop. This experiment was calculated in Serpent code by its dynamic part. During this experiment, an additional control rod for drop was placed in the reactor with a channel directly attached to the rod guide tube containing the detection system. The detection system developed for this experiment is based on diamond detectors and allows measurement of neutron flux development during the rod drop in almost point vise location. The results of both experiment and calculation showed a delay in the count rate drop influenced by the position of the rod during the drop. The obtained experience is also used in the design process of a new experimental device dedicated to rod drop measurements that will allow the direct rod position measurement during the drop. •Control rod drop experiment was performer at VR-1 reactor.•The neutron flux deformation during rod drop was measured by diamond based fast detection system.•Results from experiment were compared with Serpent dynamic calculation.