Used in atomic energy industry and defense industry: Graphite has a good neutron moderator and is used in atomic reactors. Uranium-graphite reactors are the most widely used atomic reactors. As a deceleration material in a power atomic energy reactor, it should have high melting point, stability and corrosion resistance, and graphite can meet the above requirements. The purity of graphite used in atomic reactors is very high, and the impurity content should not exceed dozens of PPM. In particular, the boron content should be less than 0.5PPM. In the defense industry, graphite is also used to make graphite nozzles for solid fuel rockets, graphite nose cones, parts of spaceflight equipment, thermal insulation materials and anti-ray materials.