核电汽机甩负荷工况除氧器瞬态分析

Transient operation analysis of tray type deaerator in nuclear power conventional island under Turbine load rejection condition

对于核电机组无论是核岛还是常规岛设备,最重要的是在运行期间保证设备安全稳定。其中一种工况就是汽机甩负荷工况,对于汽机甩负荷原因有很多,所以在系统设计时一般认为这种工况是常规工况,在该工况下,低加、高加设备及除氧器设备汽源全部失去。为防止由于温差过大造成蒸发器换热管遭到破坏,需要除氧器供水水温必须满足一定条件。除氧器必须在保压蒸汽通入之前,在凝结水不经过低压加热器加热,水温很低的条件下仍能保证给水温度不低于蒸发器所要求的供水温度,并且可以在反应堆降负荷过程中能通过保压蒸汽通入将运行参数稳定在低负荷继续运行。本文针对此种甩负荷工况下,对除氧盘式除氧器能否满足条件进行分析论证,通过对整个瞬态过程的压力、温度进行分析,最终直到整个运行工况稳定在低负荷的整个过程进行传热计算,来说明除氧盘式除氧器能良好的在该工况下稳定运行,能满足整体热力系统设计的安全性。

The most important thing is to ensure the safety and stability of equipment during operation for nuclear power unit whether it is nuclear island or conventional island. One condition is the turbine load rejection condition. There are many reasons for the turbine load rejection, so the system design is generally believed that this condition is a normal conditions. LP, HP and deaerator steam source are all lost under this conditions. In order to prevent the temperature difference caused by the evaporator heat exchange tubes are damaged, the deaerator supply water temperature must high e- nough. The deaerator must keep the temperature not less than the required water temperature of the evaporator temperature with LP out of work before maintain pressure steam into deaerator. The de- aerator can stable operating parameters continue at low load condition by maintain pressure steam in- to deaerator with the nuclear reactor process to run in low load. According to the load condition, an- alyzes whether the tray type deaerator can fit the conditions by analysis of the transient pressure and temperature until the stable operating conditions of heat transfer in the whole process of low load calculation. To illustrate tray type deaerator can fit condition well and satisfy the whole thermal system safety design.