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Description
In this work the results of modeling and simulating the burnup of the IBR-2M pulsed fast reactor in the Monte Carlo software package. A three-dimensional geometric model of the reactor has been developed, including an active zone with 64 fuel assemblies, a PO-3 reactivity modulator, a control and protection system, and a liquid metal sodium coolant. Critical calculations and simulation of the fuel campaign up to an energy production of 2040 MW∙d have been performed, taking into account two fuel refueling.
It was found that the effect of the first replacement of the simulator with a fresh fuel assembly at an energy production of 6 MW∙d∙kg-1 was ~1.55%, and at the next replacement at 18 MW∙d∙kg-1 it was ~1.43% keff. Analysis of the dynamics of the coefficients of non-uniformity of energy release showed an increase in the radial coefficient with a stable axial one, which is associated with the redistribution of the fuel mass after refueling. The critical parameters of the reactor obtained by the Monte Carlo method include keff = 1.0023, the initial reactivity margin of ~2.5 βeff and the neutron generation lifetime of 58 ns.
The results confirm the adequacy of the Monte Carlo model for predicting the behavior of the IBR-2M reactor under fuel burnout conditions and demonstrate the impact of overloads on operational stability and power distribution.
