ICONE19-43888 NUMERICAL STUDY OF THE TOXIC ELEMENTS DETERMINATION METHOD FOR THE RADIOACTIVE WASTE

With the development of the nuclear energy in the world, more and more radioactive waste is being produced. For the transport and final disposal of the radioactive waste, the radioactive waste should be checked, not only the radioactivity but also the toxic elements. The hazard of the toxic elements to the environment and biosphere is getting more and more attention from the whole world. A prompt gamma neutron activation analysis (PGNAA) system is in development to determine the kinds and amount of the toxic elements in LILW. Different with the normal PGNAA system, the target of the fast neutron coming from the neutron generator is the 200 L waste drum, which is much larger than the normal sample. Because of the large volume of the drum, the neutron moderation, absorption in the drum and the gamma attenuation in the detector are non-lineal problem. To avoid this problem, a simulation of the PGNAA system is studied to analyze the relationship between the amount of toxic elements and the spectrum of the prompt gamma ray. Based on the simulation, the fixed point iteration method is studied to determine the toxic elements.