Burnup analysis of the VVER-1000 reactor using thorium-based fuel

This paper aims to investigate Th-232/U-233 fuel cycles in a VVER-1000 reactor through calculation by computer. The 3D core geometry of VVER-1000 system was designed using the Serpent Monte Carlo 1.1.19 Code. The Serpent Code using parallel programming interface (Message Passing Interface-MPI), was run on a workstation with 12-core and 48 GB RAM. Th-232/U-235/U-238 oxide mixture was considered as fuel in the core, when the mass fraction of Th-232 was increased as 0.05-0.1- 0.2-0.3-0.4 respectively, the mass fraction of U-238 equally was decreased. In the system, the calculations were made for 3000 MW thermal power. For the burnup analyses, the core is assumed to deplete from initial fresh core up to a burnup of 16 MWd/kgU without refuelling considerations. In the burnup calculations, a burnup interval of 360 effective full power days (EFPDs) was defined. According to burnup, the mass changes of the Th-232, U-233, U-238, Np-237, Pu-239, Am-241 and Cm-244 were evaluated, and also flux and criticality of the system were calculated in dependence of the burnup rate.