206 Recovery from a Catastrophic Station Blackout (PSAM-0458)

Despite significant improvements in recent years, the Core Damage Frequency at the Surry Power Station still has a substantial contribution from catastrophic flooding. Having exhausted all realistic means of prevention, the Dominion staff has begun to evaluate means of preventing core damage in the event of an unrecoverable station blackout due to flooding. The staff has developed a strategy for taking a unit from full power conditions at the time of the blackout to a low-risk state of low temperature and pressure, with successful decay heat removal, without any emergency AC or DC electrical power and with almost no plant control.

This recovery procedure has been successfully tested on the plant simulator but still awaits verification on an engineering simulator. Results to date indicate that the core remains covered and cooled for at least 12–24 hours.

This recovery strategy is applicable in any long-term station blackout, whether due to flood, fire or any other cause.