Auxiliary Feedwater (AFW) System

The AFW is used in all pressurized water reactor designs. The main purpose of the AFW system is to provide feedwater to the steam generators to maintain a heat sink in the event of (1) a loss of main feedwater, (2) a reactor trip and loss of offsite power, and (3) a small break loss of coolant accident. The system, at some plants, can also provide a source of feedwater to the steam generators during plant startup and shutdown. However, the system cannot supply sufficient feedwater flow during power operation. At most plants, the system can only supply adequate feedwater to the steam generators with steam loads less than 5% of rated flow.

The initial system study is documented in "Auxiliary/Feedwater System Reliability, 1987-1995" (NUREG/CR-5500, Volume 1 ). The links below provide the current information for the study and latest results.

Current Results (SPAR-based):

Historical Results (SPAR-based):

Historical Results (LER based):

Supporting Information:

Page Last Reviewed/Updated Wednesday, August 31, 2022