At 0900 EDT the licensee declared an Unusual Event as a precautionary measure due to expected severe weather from
hurricane Isabel. Current wind speed and direction is 10-15 mph sustained with gusting to 20 mph from the NNE direction. No additional staff other than those for the planned outage have been brought onsite.
The licensee informed state/local agencies and the NRC Resident Inspector.
- * * * UPDATE 1608 ET FROM T. HUFF TO M. RIPLEY * * * *
As of 1600 ET, Surry Unit 1 commenced a power reduction of 200 mwe (100% to approximately 75% power) in anticipation of grid instabilities due to heavy weather. One of eight circ water screens is degraded due to river debris and its associated circulating water pump has been secured. On-site meteorological panels are out of service. Additionally, the Emergency Operating Facility (EOF) is out of service due to a loss of power.
Notified R2DO (A. Boland).
The following was received via fax from the licensee:
With Surry Power Station Unit 1 at approximately 75% reactor power and Unit 2 at 100% reactor power, a manual reactor trip was initiated on Unit 1 at 1728 and on Unit 2 at 1732, due to the loss of the '1G' and `2G' buses which supply power to all eight circulating water pumps for both units. The loss of the buses occurred during high winds and rain associated with Hurricane Isabel, although no hurricane force winds were onsite prior to or at the time of the event. A discretionary Notification of Unusual Event had been declared earlier at 0900 due to the severe weather.
On Unit 1, the 'B' inadequate core cooling monitor (ICCM) failed. The 'A' ICCM remained operable throughout. All control rods fully inserted and the shutdown margin for Unit 1 was determined to be satisfactory. On Unit 2, eight rod position indicators showed greater than 10 steps but less than 20 steps following the reactor trip. Emergency boration was initiated. All Unit 2 IRPIs [Individual Rod Position Indications] are currently indicating less than five steps and the shutdown margin was satisfactory.
Auxiliary feedwater automatically initiated as designed for both units on low low steam generator level following the trip. Primary RCS temperature decreased to approximately 543 and 538 degrees on Unit 1 and 2 respectively and was stabilized at 547 degrees.
No primary safety or relief valves were actuated during the event on either unit. As a result of the loss of the circulating water pumps, the emergency service water pumps were started to conserve intake canal level. After start, 2 out of the 3 emergency service water pumps tripped on high water temperature. The pumps were checked and restarted 14 minutes later. Also due to the need to conserve intake canal level, the main steam trip valves on both units were closed and primary temperature is being maintained by use of the secondary power operated relief valves. No indication of primary to secondary leakage exists on either unit, therefore no adverse radiological consequences resulted from this event.
Both units are currently stable at hot shutdown. At 1845, the 2G bus was energized and circulating water pumps were started. The emergency service water pumps were secured and are in standby.
This 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report is being made for Surry Units 1 and 2 in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A).
Notified R2DO (A. Boland), NRR EO (J. Calvo), DIRO (R. Wessman), FEMA (Chuck Bagwell), DHS (Colleen Wilson).
- * *UPDATE AT 1948 EDT ON 9/19/03 FROM BILL SUMMERS TO E. THOMAS* * *
The licensee terminated their unusual event due to the following conditions:
- severe weather has left the area
- both units are stable at hot shutdown on offsite power
- 2 of 3 ESW pumps are operable, and the third ESW pump is being prepared for an operational test
- 45 of 67 sirens remain inoperable, but the sirens will be restored when power to the grid is restored
The licensee will notify the NRC Senior Resident Inspector, as well as state and local officials
Notified R2DO (Boland),
NRR EO (Calvo), DIRO (McGinty),
FEMA (M. Eaches),
DHS (D. Licastro)
