A 235U mass measurement method for UO2 rod assembly based on the n/γ 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 γ-spectrometer, the n/γ 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/γ joint measurement system. The induced fission rate and the 235U abundance, thereby the 235U mass; can be obtained for UO2 rod assemblies. The 235U mass deviation of the measured value from the reference value is less than 5%. The results show that the n/γ joint measurement system is effective and applicable in the measurement of the 235U mass in samples.