核电厂DCS板卡银迁移原因分析及抑制的方法研究

Study on the Causes of Silver Migration and Its Suppression Method of DCS Card in Nuclear Power Plant

核电厂DCS板卡银迁移是集成电路装置可靠性失效的重要原因之一,针对当前DCS板卡银迁移故障频发、抑制方法空缺的情况,本文充分分析了银迁移产生的机理、DCS板卡银迁移的原因分析及定位,从软件、硬件层面,提出了银迁移的抑制方法及缓解措施,并利用寿命方程,通过HAST(高加速温度和湿度压力测试)试验加以验证。结果表明,提出的涂覆三防漆可有效抑制银迁移进程、可编程逻辑控制模块(FPGA)软件升级可有效控制银迁移的故障后果,对板卡的响应及功能不会产生影响,满足寿命要求,为核电厂的安全稳定运行提供了保障,具有实际应用价值。

The silver migration of cards of the digital control system(DCS)in nuclear power plants is viewed as one of the significant causes for the reliability failure of integrated circuit devices.In response to the frequent silver migration and unavailable suppression methods of DCS cards,this paper gives full analysis of the principle of silver migration and the causes of silver migration of DCS cards.Also,the associated suppression methods and mitigation measures on the software and hardware level are put forward and verified by life equation and the highly accelerated temperature and the humidity stress test.As shown by the results,the silver migration can be effectively retarded with the recommended conformal coating,and its failure consequences will be well mitigated by upgrading the software of programmable logic controller.Furthermore,the responses and functions of the card aren’t affected,and its life requirements are met,thereby the safe and stable operation of nuclear power plants is guaranteed.