27th International Conference Nuclear Energy for New Europe, Piran, Slovenia, 10 - 13 September 2018
Doppler broadening phenomena of nuclear cross sections due to the temperature augmentation is a crucial concern in reactor design as well as nuclear safety. This study carries out to analyze and estimate numerically the Doppler coefficient of Istanbul Technical University (ITU) TRIGA MARK II research reactor which is a pool type reactor with 250 kW power, also fueled with UZrH1.8. Moreover, a comparison between the experimental data and the numerical results is conducted. The numerical analysis is performed using Monte Carlo method-based code MCNP5, where an accurate full reactor model is developed and Evaluated Nuclear Data File ENDF6.0 library is used throughout the study. Besides, cross-sections are generated for four different temperatures using NJOY code. In this regard, reactivity feedback due to fuel temperature increase (Doppler broadening) trend is investigated and compared with the experimental data. The output of this paper gives a valuable insight on whether the fuel temperature coefficient change would influence the safety of ITU TRIGA MARK II reactor.