Emergency Power System (EPS)
The emergency diesel generator (EDG) is part of the standby emergency onsite ac power system and is required to be available as a reliable source of ac power in the event of a loss of normal ac power during all plant modes (operating or shutdown). Normally, each plant has two safety-related buses that power the electrical loads required for safe shutdown and emergency conditions. These buses typically receive power from either the auxiliary or the startup transformers, which are powered from the main generator or offsite power. In the event of the loss of offsite power or the failure of the normal power to the individual safety-related buses, an EDG train will provide a backup source of power to its associated safety-related bus. The EDG train has sufficient capacity to power all the loads required to safely shut the plant down or supply emergency core cooling system (ECCS) loads on a loss-of-coolant accident (LOCA).
An EDG train is required to automatically start upon indication of the following:
- A loss-of-coolant accident (safety injection signal)
- A low voltage condition on the safety-related bus
The initial system study is documented in "Emergency Diesel Generator Power System Reliability, 1987-1993" (NUREG/CR-5500, Volume 5 ). The links below provide the current information for the study and latest results.
Current Results (SPAR-based):
Historical Results (SPAR-based):
- EPS 2020 Summary Update
- EPS 2018 Summary Update
- EPS 2016 Summary Update
- EPS 2014 Summary Update
- EPS 2013 Summary Update
- EPS 2012 Summary Update
- EPS 2011 Summary Update
- EPS 2010 Summary Update
- EPS 2009 Summary Update
- EPS 2008 Summary Update
- EPS 2007 Summary Update
- EPS 2006 Summary Update
Historical Results (LER-based):
- EDG 2005 Summary Update
- EDG 2004 Summary Update
- EDG 2003 Summary Update
- EDG 2002 Summary Update
- EDG 1993 Executive Summary (from original NUREG)
- "Emergency Diesel Generator Power System Reliability, 1987-1993"
(NUREG/CR-5500, Volume 5 )
Supporting Information:
Page Last Reviewed/Updated Monday, September 30, 2024