Experiments for substantiation of RBMK fast-scram system based on gaseous absorber

This paper presents experiments performed in the RBMK critical facility for a substantiation of a RBMK fast-acting scram system based on the gaseous absorber - helium-3. The assignment of this system to shut-down a reactor only at accident conditions, when the standard shut-down systems do not functionate properly. Experiments were performed with a mock-up of this system in a critical configuration - the fragment of a initial reactor loading at room temperature. In first series efficiencies of helium-3 inside a superintending device or a receiving device for a range of pressure from 0.1 to 1.6 MPa were investigated. Then in transient experiments a shut-down time of 0.15-0.20 second was obtained. A comprehensive certification of core components and analyses of uncertainties were made. Experimental data can be used for neutron-code validation. (author)