Measurement of HFETR reactor power by improved ¹⁶N gamma spectrum analysis method

To increase redundancy and diversity of the reactor power measurement, a system for the measurement of reactor power can be established based on neutron activation analysis using O-16(n,p)N-16 reaction. In this work, gamma spectrums from the coolant of HFETR core are continuously detected by N-16 monitor with NaI(Tl) detector and the count rates in the spectrum range of 4.5 MeV-7.5 MeV are obtained. Meanwhile, the overlapping peaks in the given spectrum range are decomposed with LevenbergMarquardt method during the operation of HFETR. The results confirm that the count rates of full energy peak, single-escape peak and double-escape peak of 6.13 MeV gamma spectrums is proportionate to the increased reactor power measured by other monitors such as compensated ionization chamber and thermal power. It is possible to achieve the absolute nuclear power measurement by adopting the count rate of N-16 6.13 MeV peak, detection efficiency of detector and N-16 source term. (C) 2021 Published by Elsevier Ltd.