05000339/LER-2010-003

LER-2010-003, Virginia Electric and Power Company
North Anna Power Station
P. 0. Box 402
Mineral, Virginia 23117
July 26, 2010
Attention: Document Control Desk Serial No.: 10-401
U. S. Nuclear Regulatory Commission NAPS: MPW
Washington, DC 20555-0001 Docket No.: 50-339
License No.: NPF-7
Dear Sirs:
Pursuant to 10CFR50.73, Virginia Electric and Power Company hereby submit the
following Licensee Event Report applicable to North Anna Power Station Unit 2.
Report No. 50-339/2010-003-00
This report has been reviewed by the Facility Safety Review Committee and will be
forwarded to the Management Safety Review Committee for its review.
Sincerely,
Lin•q4eCtX/Ogi■It 7C9A,
N. Larry Lane
Site Vice President
North Anna Power Station
Enclosure
Commitments contained in this letter: None
cc: United States Nuclear Regulatory Commission
Region II
Marquis One Tower
245 Peachtree Center Ave., NE, Suite 1200
Atlanta, Georgia 30303-1257
NRC Senior Resident Inspector
North Anna Power Station

D
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION
(9-2007)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of
digits/characters for each block)
1. FACILITY NAME
NORTH ANNA POWER STATION , UNIT 2
4. TITLE
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not conduct or sponsor, and a person is not required to respond to, the
information collection.
2. DOCKET NUMBER 3. PAGE
05000 339 1 OF 3
Failure To Isolate Primary Grade Water To Blender Due to Operator Activities

North Anna Power Station , Unit 2
Event date:	05-28-2010
Report date:	07-26-2010
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3392010003R00 - NRC Website

1.0 DESCRIPTION OF THE EVENT On May 28, 2010, at 0004 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> North Anna Unit 2 experienced an automatic Reactor trip from 100 percent power following a lightning strike in the switchyard. At 0014 to 0027 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> a primary grade make-up to the blender was performed. Subsequently, it was determined that the surveillance requirement to ensure valves in the affected flow path are secured closed was not performed. At 0104 hours0.0012 days <br />0.0289 hours <br />1.719577e-4 weeks <br />3.9572e-5 months <br /> the primary grade (PG) supply valve (EllS System CB, Component ISV) was secured closed. However, the fifteen minute isolation requirement of Technical Specifications (TS) 3.1.8 was not met. Due to the high volume of activities associated with the automatic reactor trip and loss of power Operations personnel failed to secure the PG supply valve within the required time.

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS This event posed no significant safety implications since the normal flow control valves and other manual valves in the dilution flow path were closed. Therefore, dilution during the short time period that the PG supply valve was not secured was not possible.

This event is reportable pursuant to 10 CFR 50.73 (a)(2)(i)(B) for a condition prohibited by TS.

3.0 CAUSE The cause of the event is a human performance error with regard to proper prioritization of tasks during simultaneous activities following the automatic reactor trip of the unit.

4.0 IMMEDIATE CORRECTIVE ACTION(S) The PG supply valve was secured closed within fifteen minutes of discovery. At no time during the event did an uncontrolled dilution occur. Shutdown margin was verified to have been met.

5.0 ADDITIONAL CORRECTIVE ACTIONS Procedural and training enhancements were evaluated with regard to time critical isolation requirements. The abnormal procedure was revised and now requires the unaffected unit's Control Room Operator to ensure the PG supply valve to the Blender is secured closed.

This issue including the abnormal procedure change have been briefed with all Operations shifts.

6.0 ACTIONS TO PREVENT RECURRENCE The actions noted above are sufficient to preclude recurrence.

7.0 SIMILAR EVENTS None 8.0 ADDITIONAL INFORMATION Unit 1 was operating at 100 percent power, Mode 1, and was not affected by this event.