Year
2011
Abstract
The Korea Atomic Energy Research Institute (KAERI) has developed the pyroprocessing for over ten years to address the issues related to spent fuel of Korea. The International Atomic Energy Agency (IAEA) does not have standard safeguards procedures and criteria for pyroprocessing yet. A member state support program for the development of IAEA safeguards approach for the engineering-scale pyroprocessing facility has been carried out by KAERI since 2008. It is clear that the U/TRU ingot of pyroprocessing is the most prominent target material in terms of safeguards since its material type is metal and it contains a relatively high Pu content compared to the other processing materials. The neutron-emission rate of 10 kg of U/TRU ingot is about 5?10 8 neutrons/s from 44 g of 244 Cm isotope, and the neutron self-multiplication is over three. A Passive Neutron Albedo Reactivity (PNAR) technique which is adopting several fission chambers as neutron detectors is chosen for the non-destructive assay of U/TRU ingot to deal with the problems of high neutron-emission rate and multiplication. The Cm mass of U/TRU ingot is not a linear function of the total neutron count rate of the PNAR detector because of the neutron multiplication by fissile isotopes. The neutron multiplication of U/TRU ingot can be measured by the Cd ratio of PNAR detector and the Cm mass of U/TRU ingot is determined from the total neutron count rate with the multiplication correction. Finally, the Pu mass of U/TRU ingot is determined from the Cm mass of U/TRU ingot and the Cm ratio which is obtained in the homogeneous input powder. The Monte Carlo code simulation results show that the expected uncertainties for the determination of Cm and Pu mass of U/TRU ingot are 3.16% and 4.15%, respectively