Delayed neutron detection methods applied to the detection and location of reactor fuel element failures

A method has been developed and demonstrated to detect and locate reactor fuel element failures by means of primary coolant delayed neutron (DN) activity measurements. The initial development, done at the Knolls Atomic Power Laboratory,?? applied to a high-temperature, pressurized, recirculating water-cooled reactor system. However, it can be applied to a variety of other types of reactor systems, including air-cooled types. By this method, the state of reactor fuel integrity can be continuously and simply monitored. The actual location of fuel element failures can also be determined; in some instances this location can be accomplished without the necessity of shutting down the reactor.