Fuel Burnup Calculation in ITU TRIGA Mark II Research Reactor by Using Monte Carlo Method

This study is considered as a part of an ongoing extensive neutronics research for testing the computer model of Istanbul Technical University TRIGA Mark II research reactor. Validation of the reactor model has been successfully shown in a separate study. Thus, as a subsequent step, the primary purpose of this work is to estimate the burnup value of the fuel rods by using Monte Carlo/deterministic method and also to compare with the recorded reactor data. Operating conditions (e.g., control rod positions and material temperatures) used in the reactor model are thoroughly based on the operation number of No. 1599 from the reactor log-book as of March 2013 with a produced total energy of about 272 MWh. All the feedback effects are modelled accordingly. MONTEBURNS2 and TRIGLAV5 codes with a temperature-dependent neutron library of ENDFB/V-II. 0 are used for burnup calculations. The analyses are carried out for the cases of fission product poison free and in equilibrium. Effective core multiplication factor, k(eff), is presented as a function of total energy generated as the reactor operates at power levels of 250 kW and 10 W. This study also provides a comparison with a previous study performed using TRIGLAV code for a total produced thermal energy of 240 MWh before March 2002. The core average fuel burnup is calculated to be 0.25 MWd per fuel element while the recorded data from the log-book provides an average burnup of 0.16 MWd. In the light of current positions of control rods, this disagreement reveals that the current fuel elements possibly have more burnup than the recorded data suggest. At last, the outcomes are discussed from the refuelling strategy of the reactor core point of view.