TR-2 reactor calculations

The preliminary design calculations for the TR-2 research reactor has been made at France in 1974. First criticality was achieved in Dec. 10th, 1981; with the available HEU fuels. It has been operated at different power levels for different time intervals in the first cycle. After a 186.87 MWD's of operation, the second cycle has begun. The Xe-poisoning problem has arised in the second cycle after 80 MWD's of operation. This problem has been solved by replacing two Al blocks with two Be ref-lectors. In the meantime, core conversion activities has been initiated with the investigation of appropriate fuel type for the TR-2 reactor in 1980's. All possible LEU fuel types have been tested and optimization calculations have been covered for a new fuel design. The siliside fuels have been chosen on basis of these various design calculations and the recent developments in this type of fuels. No enlargement was necessary in the core loading, and especially, no modification was needed in the fuel element geometry, since the density of the siliside fuels could be very high. Density search calculations has been carried out to find a suitable density for the new (siliside) LEU fuels in order to achieve at least the same core performance obtained with the HEU fuels. An uranium density of 4.8 g/cc was preferred among many possible choises because of available production, which increased the core performance. 3D diffusion-burnup calculations have been made with the HEU fuels to update the core status. Many equilibrium core designs have been studied for the optimum utilization of the existing HEU and chosen LEU fuels. Mixed and fully converted equilibrium core calculations have been performed. Some of the LEU fuels have already been loaded to the TR-2 core without any operational or safety related problems. The agreement between the calculations and the experiments are quite good for the operated 13 cycles