核电站辅助系统不锈钢换热管失效研究

发布时间：2018-07-02 15:27

本文选题：不锈钢传热管 + 失效分析　；参考：《上海交通大学》2014年硕士论文

【摘要】：本文通过对某涉外核电站辅助系统的高压加热器用奥氏体不锈钢管损坏事故的调查,运用现代的失效分析方法和手段,对事故钢管取样进行宏观检查、化学成分测定、力学性能试验、金相组织检查、断口分析等手段,找到了涉外核电站高压加热器不锈钢换热管破裂的原因,提出了相应的解决办法,为保证设备安全运行,预防类似事故的发生提供了技术保障。通过失效分析发现,该高压加热器不锈钢管开裂的主要原因是在核电厂运行过程中停运,但未对加热器采取临时保护性措施,氯离子侵入,在设备重新启动前未进行清洗,导致氯离子在传热管与支撑板、管板之间缝隙处发生了浓缩沉积,形成应力腐蚀开裂。同时,通过原料管应力腐蚀试验,发现原料管供货状态存在较高的残余应力。ANSYS应力分析发现在隔板处、胀管后换热管均存在较大的内应力,在腐蚀环境和应力的双重作用下,腐蚀裂纹快速发展,从而使管子在设备运行初期即发生裂开泄漏的现象。由此,从上述事故中需要吸取的经验教训,一是要严格执行产品使用前的质量验收制度,尤其对奥氏体不锈钢管需要进行残余应力检测,并对应力腐蚀风险进行评估；二是要加强制造和安装期间设备内部清洁度的检查；三是要提高制造精度,预防传热管在隔板处发生弯曲；四是较长时间停止运行,则更应采取较为妥善的措施。唯有如此,才能保证设备的安全运行。
[Abstract]:Through the investigation of the damage accident of the austenitic stainless steel tube for the high pressure heater of a foreign nuclear power station auxiliary system, this paper uses the modern failure analysis method and means to carry out macroscopic examination, chemical composition measurement, mechanical performance test, metallographic examination, fracture analysis and other means to find the high power plant of the foreign nuclear power station. The reason for the rupture of the stainless steel heat exchange tube in the pressure heater is made, and the corresponding solution is put forward to provide technical support for the safe operation of the equipment and the prevention of similar accidents. The main reason for the cracking of the stainless steel tube in the high pressure heater is that the main reason for the cracking of the stainless steel pipe in the high pressure heater is that the heat exchanger is not transported to the heater by the temporary operation. The protective measure, chlorine ion invaded, not cleaned before the equipment was restarted, resulting in the concentration and deposition of chlorine ion in the gap between the heat transfer tube and the supporting plate and the tube plate, forming stress corrosion cracking. At the same time, through the stress corrosion test of the raw material tube, it was found that there was a high residual stress.ANSYS stress analysis found in the supply state of the raw material pipe. At the partition board, there is a large internal stress in the heat transfer tube after the tube expansion. Under the double action of the corrosive environment and stress, the corrosion crack develops rapidly, which causes the pipe to leak out in the early stage of the equipment operation. Therefore, the experience teaching training should be drawn from the above accident, one is to strictly carry out the quality acceptance before the product is used. The system, especially for austenitic stainless steel tubes, needs to be tested for residual stress and to evaluate the risk of force corrosion; two is to strengthen the inspection of the internal cleanliness of the equipment during the manufacturing and installation period; three to improve the precision of the manufacturing and to prevent the bending of the heat transfer tube at the partition board; four to stop running for a long time, then more should be taken. Proper measures. Only in this way can the safe operation of the equipment be ensured.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM623

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