The auxiliary pumps stop when the main feedwater pumps are operational. During plant shutdown During plant shutdown the auxiliary feedwater pumps can be used to supply water to cool the unit. The system pumps water from the storage tank to the steam generators. If the main feedwater system fails, the capacity of the auxiliary feedwater system is sufficient to keep an adequate level of water in the steam generators. The table below shows the capability of the auxiliary feedwater system to respond to main system failures.
Any single pump can supply the total feedwater requirements for decay heat removal of each unit.
A steam driven pump can be activated. The table below provides information about auxiliary feedwater systems at FPL nuclear plants.