A peer-reviewed journal published by K. N. Toosi University of Technology

Document Type : Research Article


Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran


‎Thorium is more abundant in nature than uranium‎. ‎The fertile thorium fuel can breed to fissile U-233 by absorbing a neutron‎. ‎The produced fissile has good neutronic performance in both thermal and fast neutron spectra‎. ‎Many types of thorium-based 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 VVER-1000 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 VVER-1000 was investigated‎. ‎The obtained results of the computational study showed the ThO2 fuel rod loading in some VVER-1000 fuel assemblies would not end to a breeding behavior of the reactor core even after one-year burnup at 3000 MW power‎. ‎However‎, ‎the enriched uranium fuel loading reduction may make a motivation for thorium fuel application in the power reactor‎.


• ThO2 fresh fuel loading in VVER-1000 power reactor does not disturb neutronic and safety parameters.

• ThO2 spent fuel of VVER-1000 power reactor suffers higher gamma dose rates than UO2 spent fuel.

• ThO2 fuel rod loading in VVER-1000 increases cycle lengths but will not result in breeding behavior.


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