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Tecson Sealing Technology

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Graphite Gaskets The Security Of The

Graphite Gaskets In the construction of nuclear power plants, a large number of nuclear grade gaskets are required. The safety, Graphite Gaskets reliability and economy of nuclear power plant production systems are largely dependent on the effectiveness of the seals. The nuclear power plant system equipment has more stringent requirements for the safety and reliability of the sealing components due to the serious and potentially significant impact of nuclear leakage.

In addition to high temperature, high pressure, Graphite Gaskets thermal fatigue conditions, the nuclear grade gasket must be equipped with radiation resistance, high reliability, high life and nuclear grade cleaning requirements, subject to compression rate, rebound rate, stress relaxation rate And the maximum leakage rate and a number of technical performance testing and heat exchange test, Graphite Gaskets in order to get permission to apply at the nuclear power plant. For the nuclear safety-related system of the gasket, mainly in the flexible graphite composite gasket-based, flexible graphite with its excellent chemical stability, soft resilience, radiation resistance and high temperature resistance, and specially designed composite Type seal structure, successfully meet the requirements of the nuclear grade seal.

Flexible graphite, also known as expanded graphite, Graphite Gaskets was developed in the 1960s as a new type of carbon graphite material, first from the United States in 1968 United carbide Corporation patent. With the petrochemical industry, as well as the rapid development of nuclear power industry, the requirements of the seal is also increasingly harsh. Despite the high price of graphite materials, Graphite Gaskets but by virtue of its series of excellent performance, still ushered in the rapid development, has become a popular new non-asbestos sealing material.

Flexible graphite and natural graphite crystal structure is the same, flexible graphite inherited the natural graphite itself, many excellent performance. However, Graphite Gaskets due to the special processing technology, resulting in changes in the microstructure of flexible graphite, so that flexible graphite also has a natural graphite does not have some special properties, its seal and the nuclear industry performance is as follows.

(1) high temperature resistance. Graphite is the highest melting point elements, flexible graphite inherited this feature, the maximum can withstand ultra-high temperature of 3650 ℃. At high temperatures, its performance is almost constant, which just adapt to the requirements of the nuclear seal, Graphite Gaskets the nuclear reactor temperature is very high, and the temperature range is also large, and flexible graphite with reliable high temperature sealing to take advantage.

(2) Corrosion resistance. Flexible graphite has a chemical inertness, the reaction activation energy is high, in addition to some strong oxidizing nitric acid, chromic acid, Graphite Gaskets fuming sulfuric acid and halogen and other media, almost no chemical corrosion, suitable for most acids, , Organic solvents and water vapor.

(3) compression resilience. Flexible graphite has a good compression rebound performance, the chemical treatment of the formation of interlayer compounds, is loose porous gas-solid two-phase structure, compared to ordinary graphite expansion of about two hundred times, is an important guarantee of compression rebound performance.

(4) Radiation resistance. In the nuclear power equipment, Graphite Gaskets the irradiation of radioactive material has a very strict requirements, and flexible graphite has a stable crystal structure, can withstand neutron rays, γ-ray, α-ray, β-ray radiation and other long-term exposure without obvious Change, so the flexible graphite into the field of nuclear seal the best choice.

(5) high purity. Nuclear reactors, the purity requirements are higher, halogen content and sulfur content of the requirements of 200ppm or less, while the purity of flexible graphite is generally up to 99% or more, so to meet the needs of the nuclear industry.