In this research, the traditional version of the phase inversion method was used to fabricate a flat sheet of a blended membrane. The method was involved using a polymer that blends polyether sulfone (PES) varied proportions (0,3,4 and 5 wt.%), and polyphenyl sulfone (PPSU) was 20wt%. It was found that with the addition of PES, the membrane properties increased, the best properties were with 4%wt. The ratio was chosen PES 4wt% to study the effect of time, temperature, and pressure on the rejection of heavy and radioactive elements. The increase in the porosity was with the addition of 4% PES. The rejection of heavy and radioactive elements for thUF membrane increases with increasing of the operating pressure and time. While by increasing the temperature, the rejection of heavy and radioactive elements for thUF membrane decreased. The rejection of K, Th, and Pb are higher than other elements, the order of the rejection is K˃Th˃Pb˃U˃Cd˃Zn˃Cu>Ni.