Preliminary Experimental and Numerical Assessment of a Secondary Scram System for Liquid Metal Cooled Reactors.

To achieve the higher safety levels they promise, all GEN-IV reactor concepts require two completely independent shutdown systems relying on different operating principles. For liquid metal cooled reactors the first system is an absorber-rod based solution. The second system that by requirement should rely on another principle. A promising new concept is also presented. This concept leads to a totally passive self activating device using small aborbing particles that flow into a dedicated channel to shutdown the reactor. The systems consists of tubes filled with particles of an absorber material . During normal operation, these particles are kept above the active core by means of a metallic seal. In case of an accident, the system is activated by the temperature increase in the coolant. This leads to melting of the metal seal. The ongoing work conducted at SCK-CEN and UCL/TERM aims at assessing the reliability of this new concept both experimentally and numerically.