The application of nodal method for dynamic analysis of TRIGA Mark II

In this paper, Nodal dynamic method is introduced to model the TRIGA Mark II reactor of the University of Pavia as a dynamic system for the total operative power range (i.e. 0-250 kW) using a zero dimensional thermal hydraulic method. Neutronic and thermal hydraulic models are coupled in order to demonstrate reactor dynamic behavior. The reactor is divided into bi-dimensional zones and simulated in Serpent 2 to obtain two group cross sections for each specified zone as well as kinetic parameters. And they are applied in nodal method for the analysis of reactor dynamic behavior. Point kinetic and nodal dynamic methods are utilized for the second core configuration as the neutronic model. Different reactivities (i.e. 190, 104, 78, 40 pcm) are inserted by control rods in different power levels (i.e. 1, 50, 100, 150 kW) for the reactor dynamic analysis. A program is written in MATLAB to couple neutronic and thermal hydraulic models. A system of ordinary differential equations are produced and solved in space state model. The calculated and experimental power excursion results are in good agreement with less than 1% difference. The results between nodal method and point kinetic method are very consistent with less than 0.05% of difference.