余热排出泵机械密封冲洗水回水温度高的分析及处理

Analysis and Treatment of High Backwater Temperature of the Heat Removal Pump

某核电站机组热态性能试验期间,余热排出泵在热备用工况下,机械密封冲洗水回水温度超出报警值。通过数值计算、整机模拟试验,对影响机械密封回水温度的各因素进行了分析论证,查明了导致机械密封冲洗水回水温度高的主要原因为喉部衬套与冷却水套节流间隙设计不合理。根据试验数据,调整间隙值由原来的0.55～0.57 mm至0.367～0.400 mm,改造方案经实施验证,回水温度由85℃降至43℃,温度降至报警值以下。

During the hot function test of a nuclear power plant,the pump of residual heat removal system is under hot standby working condition,and the backwater temperature of the mechanical seal has exceeded the alarm value.By means of numerical calculation and function test,the factors which affect the mechanical seal the return water temperature are founded.It is determined that the main factors influencing the mechanical seal washing water temperature are that the clearance between throat bushing and cooling jacket throttling is not reasonable.According to the test results,the clearance value is adjusted from 0.55~0.57 mm to 0.367~0.400 mm,and the backwater temperature is then reduced from 85℃ to 43℃,which is below the alarm threshold.