The following information was provided by the licensee via email:
At 1228 CDT on October 27, 2022, Grand Gulf Nuclear Station (GGNS) was in Mode 1 at 88 percent power when a failure of a draw down surveillance resulted in the loss of secondary containment. During the performance of the surveillance GGNS was unable to maintain secondary containment pressure, as required by Technical Specification Surveillance Requirement 3.6.4.1.4, greater than or equal to 0.266 inches of water vacuum for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate of less than or equal to 4000 cfm.
The test was secured. Secondary containment was declared inoperable and Technical Specification 3.6.4.1 A.1 was entered at 1228 CDT. Secondary containment was restored to operable status at 1240 CDT by restoring the configuration to a previously known operable condition.
This event is being reported as an event or condition that could have prevented the fulfillment of a safety function.
The NRC Resident Inspector was notified.
