This paper presents results of a feasibility study aimed at developing a "zero-transuranic-discharge" fuel cycle based on partial replacement of uranium by thorium as a fertile component. The design objective is to find a mixture of thorium (Th), enriched uranium (EU) and transuranic (TRU components resulting in an equilibrium charge-discharge mass flow. The quantity and isotopic vector of the TRU component will be identical at the charge and discharge time points, thus allowing the whole amount of the TRU at the discharge to be reloaded into the following cycle (excluding the reprocessing losses). The results demonstrate the neutronic feasibility of a fuel cycle with a "zero-TRU" discharge. This was accomplished by developing a specific fuel composition based on a mixture of Th-U-TRU components. The reactivity coefficients were found to be within a range typical for a reference PWR core. The soluble boron worth is reduced by approximately a factor of two from a typical PWR value, which presents a design challenge.