Halogen-free inflaming retarding insulating material of nuclear cable and cable insulating layer as well as preparation method and application thereof

The invention discloses a halogen-free inflaming retarding insulating material of a nuclear cable and a cable insulating layer as well as a preparation method and an application thereof. The halogen-free inflaming retarding insulating material of the nuclear cable comprises raw materials as follows: a polymer substrate comprises the components of: 100 parts of low-density polyethylene and ethylene propylene diene monomer; an inorganic flame retardant comprises the component of: 70-100 parts of magnesium hydroxide; a polyphosphazene flame retardant comprises the component of: 10-20 parts of hexaphenoxycyclotriphosphazene; a compound antioxidant comprises the components of: 4-8 parts of a main antioxidant, an auxiliary antioxidant and an ultraviolet absorbent; an anti-irradiation agent comprises the components of: 5-15 parts of an anti-irradiation agent A and an anti-irradiation agent B; a machining auxiliary agent comprises the components of: 4-10 parts of a cross-linking sensitizer and a lubricating agent, wherein the anti-irradiation agent A is high phenyl silicone rubber and/or phenylene silicone rubber; and the anti-irradiation agent B is boron carbide and/or boron nitride. The insulating material has the stable irradiation performance and electric performance, and good inflaming retarding performance, and is low-smoke, halogen-free and low-toxin.