An Engineering Evaluation was initiated to assess the potential for
CO2 [carbon dioxide] migration in the event of a
CO2 fire suppression system discharge in the Salem Unit 1 and 2 - 4160 volt or 460 volt Switchgear Rooms or Lower Electrical Penetration Areas. The results presented in the evaluation conservatively identified that when
CO2 systems are discharged,
CO2 migration can result in concentrations in some adjacent areas that would require the use of self-contained breathing apparatus (
SCBAs) for entry, or in some cases should be restricted to transit activities only.
Some of these adjacent areas are required to be accessible by operators to perform manual actions in the plant to achieve and maintain safe shutdown. Based on the time line established in the Salem Manual Action Feasibility Studies for operator actions in the response to a fire in a Switchgear Room, the ability to shutdown the plant in the event of a fire concurrent with a CO2 discharge could be impacted.
The immediate action is to isolate the CO2 system and implement the necessary compensatory measure for the inoperable CO2 system as delineated within Station Fire protection program. With the CO2 systems isolated, the ability to safely shutdown the plant in the event of a fire in these areas is restored. Additional actions are being evaluated at this time to restore the CO2 system.
This event is being reported in accordance with 10CFR50.72(b)(3)(v) and Salem Unit 2 License Condition 2.I. No ESF, ECCS or safety related equipment has been impacted by this condition. Both Units remain at 100% power. There were no personnel injuries associated with this condition.
Lower Alloway Creek Township and the State of New Jersey will be notified.
The NRC Resident Inspector was notified of this event by the licensee.
