 Cadmium is used in the control rods of nuclear reactors , acting as a very effective " neutron poison " to control neutron flux in nuclear fission . When cadmium rods are inserted in the core of a nuclear reactor , cadmium absorbs neutrons preventing them from creating additional fission events , thus controlling the amount of reactivity . The pressurized water reactor designed by Westinghouse Electric Company uses an alloy consisting of 80 % silver , 15 % indium , and 5 % cadmium . 
