γ辐照对高导热聚乙烯微纳米复合介质绝缘劣化的作用机理及材料性能优化研究

Polyethylene(PE) used as insulating material of cable in nuclear power plant is subjected to γ-ray irradiation and high temperature, by which the insulation property of the material tends to be deteriorated. Accordingly, it is very important to improve the endurance to γ-ray irradiation as well as to high temperature of PE. This project plans to prepare PE based micro-nanocomposites with excellent insulating property and high thermal conductivity by loading micro- and nano-sized inorganic particles into neat PE so as to improve its insulation property under the radioactive and high temperature environment. The composites are planned to be irradiated by a Cobalt-60 gamma source, after which the effect of the irradiation condition on the physical as well as chemical structure, insulation property and thermal conduction property will be estimated. The dependence of the properties of the composites upon irradiation condition and filler characteristics will be revealed. The purpose of this project is to find a optimal method for preparing the composites that have the most excellent insulation property and thermal endurance after γ-ray irradiation. Such a finding will provide helpful information for the safe operation of cable used in nuclear power plants.

应用于核电站电缆绝缘的聚乙烯材料因高能γ辐照和高温作用而导致其绝缘性能下降，提高聚乙烯的耐γ辐照和耐热性能对保障电缆绝缘的长期安全运行具有重要的理论意义和工程实用价值。本项目拟采用微、纳米无机颗粒修饰聚乙烯基体，制备高导热聚乙烯微纳米复合介质，旨在提高其在强辐照和高温环境下的绝缘性能。采用钴-60γ射线源对复合介质进行辐照处理，研究γ辐照条件对复合介质的理化结构、绝缘和导热性能的影响规律及机理，分析辐照前后复合介质的绝缘、导热性能对微纳米无机颗粒特征参数的依赖性，揭示微、纳米无机颗粒在γ辐照诱导的化学反应过程中的本质作用，找到辐照前后复合介质的理化结构与绝缘、导热性能之间的内在联系，探寻可显著提高聚乙烯绝缘材料耐辐照和耐热性能的微纳米无机颗粒优化特征参数和相应的复合介质制备方法，为保障核电站电缆绝缘的安全运行、延长其使用寿命奠定实验和理论基础。

应用于核电站绝缘的聚合物材料因高能γ辐照和高温作用而导致其绝缘性能下降，提高聚合物的耐γ辐照和耐热性能对保障电缆绝缘的长期安全运行具有重要的理论意义和工程实用价值。本项目采用微、纳米无机颗粒修饰聚乙烯基体，制备高导热聚乙烯微纳米复合介质，旨在提高其在强辐照和高温环境下的绝缘性能。采用钴-60γ射线源对复合介质进行辐照处理，研究γ辐照条件对复合介质的理化结构、绝缘和导热性能的影响规律及机理，分析辐照前后复合介质的绝缘、导热性能对微纳米无机颗粒特征参数的依赖性，揭示微、纳米无机颗粒在γ辐照诱导的化学反应过程中的本质作用，找到辐照前后复合介质的理化结构与绝缘、导热性能之间的内在联系，获得了可显著提高聚乙烯绝缘材料耐辐照和耐热性能的微纳米无机颗粒优化特征参数和相应的复合介质制备方法。本项目拓展性地开展了关于γ辐照对环氧树脂(EP)及其纳米复合材料的绝缘性能影响研究、模拟核电站失水事故条件下环氧基纳米复合材料的绝缘失效机理研究、γ辐照对聚酯薄膜(PET)电荷输运特性的影响研究以及7.5 MeV电子束辐照对EP及其纳米复合电介质绝缘性能的影响研究。揭示了γ辐照对EP/Al2O3纳米复合材料理化结构、电荷输运特性和耐局部放电侵蚀性能的影响规律，分析了模拟核电站失水事故对EP/Al2O3纳米复合材料理化结构、电荷输运特性和表面电荷积聚特性的影响，阐明了γ辐照对商用PET薄膜理化结构和电荷输运特性的影响机理。另外，采用7.5 MeV电子束辐照EP及其纳米复合材料，研究了电子束辐照作用下试样的理化结构、电荷输运和耐局部放电侵蚀性能的变化规律。本项目为保障核电站电缆绝缘的安全运行、延长其使用寿命奠定实验和理论基础。