A U-235 mass measurement method for UO2 rod assembly based on the n/gamma joint measurement system

Fast-Neutron Multiplicity Counter based on Liquid Scintillator Detector can directly measure the fast neutron multiplicity emitted by UO2 rod. HPGe gamma spectrometer; which has superior energy resolution; is routinely used for the gamma energy spectrum measurement. Combing Fast-Neutron Multiplicity Counter and HPGe gamma-spectrometer, the n/gamma joint measurement system is developed. The fast neutron multiplicity and gamma energy spectrum of UO2 rod assemblies under different conditions are measured by the n/gamma joint measurement system. The induced fission rate and the U-235 abundance, thereby the U-235 mass; can be obtained for UO2 rod assemblies. The U-235 mass deviation of the measured value from the reference value is less than 5%. The results show that the n/gamma joint measurement system is effective and applicable in the measurement of the U-235 mass in samples. (C) 2019 Korean Nuclear Society, Published by Elsevier Korea LLC.