Full core fuel burnup assessment of the ITU TRIGA Mark II research reactor using gamma spectroscopy

This study investigates the burnup distribution of fuel elements in the ITU TRIGA Mark II research reactor core through gamma spectroscopy using 137 Cs as a burnup indicator. Non-Destructive Assay (NDA) techniques were employed to analyze fuel depletion, utilizing a specialized fuel investigation system installed above the reactor pool. The results indicate that the highest burnup values, exceeding 5 %, were concentrated in the inner core rings (B and C) due to intense neutron flux exposure, while the outer rings (D, E, F) exhibited lower burnup levels. To address this asymmetric distribution, a proposed fuel reshuffling strategy was analyzed, aiming to optimize neutron flux balance and enhance fuel utilization. Also, the strong correlation between 137 Cs activity and burnup values confirms its reliability as a burnup indicator.