Rod changing system and method for reactor of nuclear power plant

The invention discloses a nuclear power plant reactor rod changing system and method, and the system comprises a power judgment unit which is used for judging whether the power of a primary loop is stable or not, and generating a judgment result for representing whether the power of the primary loop is stable or not; the power fluctuation prevention unit is used for monitoring the fluctuation state of the primary loop power in real time; and the rod replacement execution unit is used for sequentially carrying out rod position exchange processing on the first T rod group and the second T rod group included in each temperature rod group according to the fluctuation state after determining that the power of the primary loop is stable. By means of the automatic rod replacing device, rod replacing work can be efficiently, stably, reliably and automatically achieved, the defects of large waste water generation amount, low automation level, poor flexibility, severe shadow effect and the like are overcome, the worklo