To modify the porosity of PAN-4A composite beads, PVP polymer was used. The optimum viscosity of the dope for the preparation of spherical beads is 470 -480 cP. The porosity of composite beads was increased up to 75 percent (by volume) at the ratio of PVP/PAN = 1.0. PAN-4A composite beads were stable in acid solution of pH = 2 and radiation dose up to 1.89 MGy. The ion exchange tests showed that PAN-4A composite ion exchanger was selective for Sr z+. Distribution coefficients for Sr2+and Cs + at pH = 2 were 2 x 104 mL/g and 280 mL/g, respectively. Ion exchange capacities (Qm) modelled by Dubinin-Polanyi equation were 3.92 meq (Sr2+)/g and 2.47 meq (Cs+)/g, respectively. The uptake rates of PAN-4A for Sr ions were improved by PVP addition. The total effective diffusivities were of the order of 10 -8 cm2/sec for both strontium and caesium ions.