Kinetic study of the Tehran research reactor core with low enriched fuel

For evaluating the performance of the newly refuelled Tehran Research Reactor core with low enriched uranium fuel (LEU) in transient states a two group time dependent diffusion equation code (COSTANZA) was used. This paper presents results of calculations of the fast transients, revealing the steady performance of the core and fuel integrity during transient for a probable reactivity insertion of less than or equal $1.5/0.5 s. The temperature dependant reactivity coefficients of the Doppler resonance broadening effect and of the moderator absorption cross section change and density dilution were calculated using cell-averaged 69 energy group WIMS-D/4 for two main libraries, old library and WIMKAL88, to 13 groups. The two group parameters for the COSTANZA code were also obtained by WIMS-D/4.