Mismanagement or control rod failure have often been blamed for nuclear accidents , including the SL-1 explosion and the Chernobyl disaster . '' Homogeneous '' neutron absorbers have often been used to manage criticality accidents which involve aqueous solutions of fissile metals . In several such accidents , either borax ( sodium borate ) or a cadmium compound has been added to the system . The cadmium can be added as a metal to nitric acid solutions of fissile material ; the corrosion of the cadmium in the acid will then generate cadmium nitrate '' in situ ''
SL-1
SL-1
Control rod