A set of potential parameters for modeling zircon structure by atomistic simulation techniques was obtained in this paper. A reasonable structure model of zircon was established by fitting important properties of zircon. Based on the equilibrium configuration
the formation energies of the basic point defects and the intrinsic disorders in zircon were calculated. The calculated heats of solution of substituting Pu for Zr in different ratios showed that there was an immiscible gap at the composition ratio (Pu 75mol%-Zr 25mol%)
which means that the amount of substituting Pu for Zr should be confinded in 50mol% when using zircon to immobilize Pu.