This report is being made under
10CFR50.73 (a) (2) (iv) (A).
On September 27, 2003, at 0118 hours0.00137 days <br />0.0328 hours <br />1.951058e-4 weeks <br />4.4899e-5 months <br /> Central Time, while operating at 100 percent power, Grand Gulf Nuclear Station experienced an invalid actuation of the High Pressure Core Spray (HPCS) System. The invalid signal was the result of an error made while performing a continuity check during a quarterly surveillance.
The invalid HPCS initiation caused the following systems to actuate: HPCS Pump, Division III Diesel Generator (DG) and Standby Service Water (SSW) 'C' (as designed to support DG operation).
Each train actuation was complete, HPCS started and functioned as designed and all support systems functioned properly.
There was an unexpected HPCS pump suction valve transfer to Suppression Pool. The most probable cause of this valve transfer was minor oscillation in Suppression Pool level.
The licensee informed the NRC Resident Inspector.
