Today thorium based fuels are being investigated as possible alternatives in fuel technology. However, the majority of thorium fuel research studies are limited to reactor physics investigations, and there are concerns about dose evaluation and shielding of such spent fuels. The present work investigates burn-up behavior of thorium oxide fuel in Tehran research reactor. The fuel gamma dose rates are calculated at different burnups and cooling TIMEs. A comparison between the reactor routine fuel and the thorium oxide fuel is conducted to reveal shielding challenges of the thorium-based fuel application. Despite the U3O8-Al routine fuel, the obtained results showed that ThO2 gamma dose rates are completely dependent on the burn-up values. In addition, for transporting the spent ThO2 fuel with the routine transport casks, there is a necessity for the higher cooling TIMEs compared with that of U3O8-Al. Otherwise, construction of thicker transport casks is needed to transport the thorium-based spent fuel in shorter TIMEs.