核电站HDPE管道材料在海水中的辐射老化研究

Radiation Aging of HDPE Pipeline Materials of Nuclear Power Plant in Seawater

采用人工加速老化的方法模拟了排热用高密度聚乙烯(HDPE)海水管道在核电厂环境中的老化过程,对浸泡在海水中的样品进行了不同辐照剂量的照射,通过对辐照前后样品的凝胶含量、力学性能、自由基浓度以及结晶度的测试探究了辐照对浸泡在海水中的HDPE管道的影响及相关机理。单电子自旋测试(ESR)结果表明随着辐照剂量的增加会提升浸泡在海水中样品的自由基含量;力学性能测试结果表明,辐照会降低HDPE样品的断裂伸长率并小幅提升其拉伸强度;凝胶含量测试表明辐照会提升样品的交联程度;而通过红外光谱和差示量热扫描仪的测试结果显示,辐照会破坏浸泡在海水中的样品的结晶,使结晶度快速降低。

The aging process of high-density polyethylene(HDPE)seawater pipeline in nuclear power plant was simulated by artificial accelerated aging method.The samples immersed in seawater were irradiated by different doses of radiation.The aging process and mechanism of HDPE pipeline were investigated by testing the gel content, mechanical properties, free radical concentration and crystallinity of the samples before and after irradiation.The results of single electron spin test(ESR)show that the contents of free radicals in samples increase with the increase of irradiation dose.The mechanical properties show that irradiation could reduce the elongation at break of HDPE samples and slightly increase their tensile strength.Gel contents test shows that irradiation increases the cross-linking degree of samples.And the results of infrared spectroscopy(FTIR)and differential scanning calorimetry(DSC)show that the irradiation can destroy the crystallization of the sample immersed in seawater and make the crystallinity decrease rapidly.