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  • 1 Korea Atomic Energy Research Institute 150-1 Duckjin-Dong Yuseong, Daejeon Korea
  • 2 Koreae Institute of Nuclear Nonproliferation and Control Expo-ro 573 Yuseong, Daejeon Korea
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A delayed neutron counting system has been implemented at the HANARO research reactor in 2007. Thermal neutron flux measured at the NAA #2 irradiation hole coupled to the delayed counting system, was higher than 3 × 1013 n cm−2 s−1. The delayed neutron counting system is composed of 18 3He detectors which are divided into three groups with six detectors and the collected signals of each group are processed to a digital signal. The count numbers were measured with the uranium mass by using NIST SRMs under fixed analytical condition and their correlation could be determined. Finally, delayed neutron activation analysis has been carried out for the determination of uranium mass fraction in the collected environmental samples.