▎ 摘　　要

NOVELTY - Double-layer coating material suitable comprises sealing primer and elastic topcoat. The sealing primer is aqueous two-component epoxy resin, and the elastic topcoat includes aqueous polyurethane resin, nano-silica sol, graphene oxide and nano-silver powder. USE - The double-layer coating material is useful for removing polonium 210 pollution on the ground in nuclear facility. ADVANTAGE - The sealing primer has good sealing and shielding performance, adhesion performance and flexibility, and prevents polonium 210 from penetrating into the substrate. The elastic topcoat has a good adsorption function for polonium 210 to fix polonium 210, and has good adhesion performance, service life (2-3 years) and construction performance, which is conducive to peeling off the entire double-layer coating for replacement. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: a preparation method of the double-layer coating material, comprising mixing component A and component B according to -NH/-COC=0.7-0.9 to obtain a sealing primer, and uniformly mixing components of the elastic topcoat and grinding to obtain the elastic topcoat; and a construction method of the double-layer coating material, comprising coating the sealing primer on the ground in the nuclear facility, and curing to obtain sealing primer coating, and spraying the elastic topcoat on the sealing primer coating.