An Accelerator-Based Transuranic Waste Assay System

Development of a system for the assay of waste materials at the Idaho National Engineering Laboratory is discussed. The assay method uses photons, available from bremsstrahlung, to induce fission in transuranic (TRU) materials. Radiations emitted following fission are detected and used to quantify the TRU. Reasons for the selection of the technique will be presented. The experimental program and development of appropriate instruments will be described. Experimental results and difficulties with this application of accelerators are also presented. Present detection limits for natural uranium are 110 mg using 8 MeV electrons and counting prompt neutrons and 36 mg using 16 MeV electrons and counting delayed neutrons. Both detection limits are determined using 4000 ¿C of accelerated charge. The instrument system is capable of counting prompt neutrons as soon as 30 ¿s after the "gamma flash" with 16 MeV electrons and 500 mA beam current.