核电站集散控制系统机柜故障分析与改进研究

Analysis of Typical Abnormalities and Improvement Measures of DCS Cabinet in Nuclear Power Plant

某核电厂是国内第三代核电,是首个采用集散系统的数字化仪控核电站。集散系统的安全性、稳定性、高效性运行是保证核电站生产、经营的基础,是保证核电厂发电量稳定输出的基本要求。2015年12月13日,某核电站2号机组分散控制系统(以下简称DCS)仪控自动处理器机柜故障,对机柜故障的原因进行分析,确定为运行环境不良导致自动处理器(AP)机架背板电子元器件存在电化学腐蚀(氯、硫)和物质迁移现象,处理器机架信号控制引线与接地端(M)存在漏电,禁止输出(BASP)信号不稳定,机架背板电路板电路短路,触发集散控制逻辑系统连锁保护,导致机组停堆停机事件发生。针对事件的原因分析,制定了针对性的改进措施和维护策略,有效地保证机组安全稳定运行。

Certain nuclear power plant is the third generation nuclear power in China,and it is the first digital instrument-controlled nuclear power plant with distributed system.The safety,stability and efficient operation of the distributed system are the basis for ensuring the production and operation of nuclear power plants,and the basic requirements for ensuring the stable output of power generation in nuclear power plants.On December 13,2015,the instrument and control automatic processor cabinet of distributed control system(hereinafter referred to as DCS)of Unit 2 of a nuclear power plant failed.By analyzing the causes of the cabinet failure,it was determined that the poor operating environment caused electrochemical corrosion(chlorine,sulfur)and material migration of electronic components on the back plate of the automatic processor(AP)rack,and the electrical leakage between the signal control lead and the ground terminal(M)of the processor rack,and the signal of the prohibited output(BASP)was unstable.According to the analysis of the cause of the incident,the corresponding improvement measures and maintenance strategies are formulated to effectively ensure the safe and stable operation of the unit.