Nano silica particles were tested to remove some radionuclides (R.Ns) from primary coolant water through different experiments. A simulation of the R.Ns such as Strontium (Sr), Nickel (Ni) and Cobalt (Co) was conducted by using the same chemical elements. From experiments, the adsorption capacity values at elements of concentration 400mg/l were 19128, 18270 and 19728mg/g, respectively. The analysis of the adsorption phenomena was described through different kinetic factors, adsorption isotherms, and thermodynamic parameters. From the data of experiments, The amount of elements adsorbed by nano particles (qe cal ) was the same for three elements and equal 20000 mg/g in the pseudo second order model. By the intraparticle diffusion model, the qe cal values were equal 19024, 18006 and 19131mg/g, respectively. It meant a very strong chemical adsorption process. In Freundlich isotherm, the calculated correlation factors of three elements were 0.979, 0.992 and 0.990, respectively. These results confirmed the heterogeneity of nano-silica surface and the adsorption was multilayer and cooperative process. From D-K-R isotherm, the calculated energies were 316.23, 316.23 and 353.55 kJ mol-1, respectively. From the thermodynamic results, the reaction for the three elements was spontaneous. This work confirmed that the nano silica could be good adsorbent material for removing R.Ns.