Feasibility study of application of ThO2 fuel rods in VVER-1000 fuel assemblies using MCNP and ORIGEN codes

‎Thorium is more abundant in nature than uranium‎. ‎The fertile thorium fuel can breed to fissile U233 by absorbing a neutron‎. ‎The produced fissile has good neutronic performance in both thermal and fast neutron spectra‎. ‎Many types of thoriumbased fuels were applied in different nuclear reactors‎. ‎Also natural thorium oxide is used as seed/blanket configuration that the ThO2 rods are used in the outer sections of any fuel assembly‎. ‎The present study aims to investigate the ThO2 fuel rod loading in 3000 MW VVER1000 power reactor‎. ‎MCNPX and ORIGEN codes were used to evaluate its effects on the core neutronic‎. ‎In addition‎, ‎the gamma emission rates of ThO2 spent fuel than the UO2 routine fuel of VVER1000 was investigated‎. ‎The obtained results of the computational study showed the ThO2 fuel rod loading in some VVER1000 fuel assemblies would not end to a breeding behavior of the reactor core even after oneyear burnup at 3000 MW power‎. ‎However‎, ‎the enriched uranium fuel loading reduction may make a motivation for thorium fuel application in the power reactor‎.