Abstract
The auxiliary external power Qinfang 2P70 of Fangjiashan NPP need to be shutdown, which makes one way the external power unavailable, thus affecting the safety level of the plant. In this paper, Through the internal event level PSA model, internal event LERF model, internal fire model and internal water flooded model, during Fangjiashan at power, 2P70 shut down caused one way the external power unavailable, gives the safety assessment results, And put forward the close attention of the important equipment such as the main power grid and the diesel engine. The test and maintenance of the diesel engine and the SEC/RRI heat exchanger are prohibited. The risk of the unit is managed and controlled by a series of other measures. The risk monitor is used to supervise the unit in real time. Finally, the application risk monitor of the power plant is discussed. The necessity and the PSA method to evaluate the possibility of auxiliary transformer shutdown to generalize to generating units.
