In LWRs, Gd2O3 is loaded in several fuel assemblies as burnable poison for controlling excess reactivity of the fresh fuel and the reactor core at the beginning of burnup stage. The purpose is to avoid an excessively high power peak at some fresh fuel assemblies. After a burnup level of about 10-15 GWd/t, main absorbing isotopes, Gd155 and Gd157, are depleted completely and the reactivity decreases with burnup linearly similar to other assemblies without Gd2O3. In conventional design, Gd2O3 is mixed homogeneously with UO2 in specific fuel pins. Since Gd2O3 has a smaller thermal conductivity than that of UO2, its content leads to the decrease of the thermal conductivity of the fuel pellet. An investigation of the effect of Gd2O3 dispersion on the thermal conductivity shows that 10 wt\(\) Gd2O3-dispersed UO2 pellet has the thermal conductivity of about 5.8-2.7 W/mK in the temperature range from 300 to 1273 K which is larger than that of homogeneous mixed solid solutions (3.8 to 2.6 W/mK) with the same Gd2O3 content [1]. This means that the use of Gd2O3 particles improves the thermal conductivity of UO2-Gd2O3 pellets effectively. In the present work, we investigated the neutronics feasibility of using Gd2O3 particles for reactivity controlling and the effect on the neutronics performance of VVER-1000 fuel assembly. The k∞ curve for the case of Gd2O3 spherical particles with the radius of 20 µm was obtained as shown in Fig. 1 which is similar to that of the conventional design with homogeneous mixed Gd2O3. Other neutronics characteristics are also investigated and compared to that of the conventional design.