China's coal accounts for 70% of primary energy consumption. The large consumption of fossil energy makes China the second largest carbon dioxide emitter in the world. Nuclear energy has the outstanding advantages of green, high efficiency, low carbon emissions and scale production. An important choice for change, China's development of nuclear power can not only solve the power supply problem, but also adjust the energy structure and reduce carbon emissions. According to the Medium- and Long-Term Development Plan for Nuclear Power (2005-2020) adopted by the National Development and Reform Commission in October 2007 [1], by 2020, China’s nuclear power installed capacity will reach 40 million kilowatts; however, by 2010, this The target can no longer meet the needs of social and economic development, and the installed capacity of nuclear power will reach 70 million to 80 million kilowatts. By 2030, the installed capacity of nuclear power will increase to 200 million kilowatts, and in 2050 it will increase to 400 million kilowatts. China has built four nuclear power bases in Qinshan, Zhejiang, Daya Bay in Guangdong, Tianwan in Jiangsu and Lingao in Guangdong. There are 13 nuclear power units in operation and an installed capacity of 10.8 million kilowatts.

The 1E-class K1 double-wall heat-shrinkable tube for nuclear power plants is used for terminal connection of wires and cables in the nuclear island. It not only protects the wires and cables under normal environmental conditions, but also protects the earthquake load and accident environment. After the accident, the wire and cable can be sealed and insulated. In the past, only a US TYCO company was able to provide 1E-class K1 double-wall heat-shrinkable tubes for nuclear power plants. China's nuclear power plants use 1E-class K1 heat-shrinkable tubes all rely on imports. Now our own double-wall heat-shrinkable tubes can also be related. standard.

The 1E grade K1 double-wall heat-shrinkable tube structure for nuclear power plant is composed of two layers, the outer layer is a heat-shrinkable layer, and the inner layer is a hot-melt adhesive layer, which is mainly composed of ethylene propylene diene monomer and ethylene-vinyl acetate copolymer. When in use, the outer layer shrinks with heat, and the inner layer melts with heat. Under the action of the outer layer contraction force, the inner layer hot melt adhesive will closely bond the protected portion and the outer layer to prevent moisture from entering the protected portion.

双壁热缩管在核电站上的应用

中国煤炭在一次能源的消费中占70%，大量的消耗化石能源使得中国成为全球第二大二氧化碳排放国，核能具有绿色、高效、低碳排放和可规模生产的突出优势，发展核电是应对气候变化的重要选择，中国发展核电不仅能解决电力供应问题，而是能调整能源结构，减少碳排放。据国家发展和改革委员会2007年10月通过的《核电中长期发展规划（2005-2020年）》[1]，到2020年，我国核电运行装机容量达到4000万千瓦；然而到了2010年，这一目标已经不能满足社会经济发展的需要，调整为核电装机容量达7000万～8000万千瓦，到2030年，核电装机将提高到2亿千瓦，2050年则将提高到4亿千瓦。中国已建成浙江秦山、广东大亚湾、江苏田湾和广东岭澳四个核电基地，现役核电机组13台、装机容量1080万千瓦。

核电站用1E级K1类双壁热缩管用于核岛内电线电缆的终端连接，不但要在正常环境条件下，对电线电缆起到密封和绝缘保护作用，而且还要在地震荷载、事故环境以及事故后能对电线电缆起到密封和绝缘保护作用。以前世界上只有美国TYCO一家公司能够提供核电站用1E级K1类双壁热缩管，我国的核电站用1E级K1类热缩管全部依赖进口，现在我们自己的双壁热缩管也能达到相关标准。

核电站用1E级K1类双壁热缩管结构，由双层构成，外层为热缩层，内层为热熔胶层，主要由三元乙丙橡胶和乙烯——醋酸乙烯共聚物构成。使用时，外层遇热收缩，内层遇热熔化，在外层收缩力的作用下，内层热熔胶会将被保护部位与外层紧密地粘结在一起，防止潮气进入被保护部位。