05000338/LER-2010-005
| Telephone Number (Include Area Code) | |
| Event date: | 12-12-2010 |
|---|---|
| Report date: | 02-03-2011 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| LER closed by | |
| IR 05000338/2011003 (28 July 2011) | |
| 3382010005R00 - NRC Website | |
1.0 DESCRIPTION OF THE EVENT On September 19, 2010, Unit 1 was in Mode 5 during a refueling outage with the Unit 1 "A" Charging Pump, 1-CH-P-1A (El IS System CB, Component P), tagged out. This pump also serves as a High Head Safety Injection (HHSI) Pump (EllS System BQ, Component P).
Medium Risk Scaffolding (non-seismic) was erected in the pump cubicle for outage-related maintenance. Operations approval of the scaffold had the stipulations that the scaffold not be erected prior to entering Mode 5 and be removed prior to entering Mode 4. Per the scaffolding administrative procedure, only a Medium Risk scaffold was required with the pump tagged out and the Unit in Mode 5. High Risk (seismic) scaffolding would be required if the Unit was in Modes 1-4. On September 27, 2010, the scaffold tracking status was incorrectly updated to Removal Complete (RC) with the scaffold still erected in the field.
Unit 1 entered Mode 4 at 0013 on October 10, 2010. On December 12, 2010, the Medium Risk (non-seismic) scaffolding was discovered in the pump cubicle, rendering the pump inoperable, but still available, for a period of time that exceeded the Technical Specification allowed outage time. In addition, on November 9, 2010, with the Unit 1 "A" Charging Pump in service, the Unit 1 "B" Charging Pump was declared inoperable for approximately two hours to perform surveillance testing. This is also a condition prohibited by Technical Specifications. The scaffold was removed on the day of discovery.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS This event posed no significant safety implications since a seismic event did not occur while the scaffolding was erected and redundant pumps were available at all times.
Therefore, the health and safety of the public were not affected by this event.
This event is reportable pursuant to 10 CFR 50.73 (a)(2)(i)(B) for a condition prohibited by Technical Specifications.
3.0 CAUSE The direct cause of this event was a human error (Inattention to Detail — Unawareness) in updating the status of the scaffold package in the tracking program caused either by poor work practices or communication. The human error was made by a supplemental employee, not currently employed at North Anna Power Station (NAPS), and the exact direct cause could not be determined. The human error prevented the scaffold from being identified as an erected scaffold requiring removal prior to entry into Mode 4.
The apparent cause of this event was an organization to program interface deficiency (Inadequate Program or Process Implementation) in that the electronic scaffold tracking function was not effectively implemented at NAPS. As a result, appropriate verification practices and supervisory oversight were not established over changes to the scaffold status to prevent a single human error from resulting in an event.
4.0 IMMEDIATE CORRECTIVE ACTION(S) The Technical Specification action was entered at the time the scaffolding was discovered in the Unit 1 "A" Charging Pump cubicle. The pump was placed in PULL-TO-LOCK with the Unit 1 "C" Charging Pump, powered by the "H" Emergency Bus, in service at the time and the associated actions were cleared. The scaffolding was removed from the pump cubicle and then the pump was returned to AUTO.
5.0 ADDITIONAL CORRECTIVE ACTIONS The Scaffolding Order will be removed from a scaffold at the time of dismantling and shall be "in hand" when updating the status of that scaffold in the scaffold tracking program. Non supervisory personnel will be required to obtain a second verification prior to updating scaffolding status. These process enhancements have been implemented.
The scaffold tracking function using electronic Scaffold Orders with electronic approvals and signatures will be fully implemented. The use of hard copy Scaffold Orders will be discontinued. This item will be tracked to completion via the Corrective Action System.
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 2 was in Mode 1, 100 percent power, at the time of this event and was not affected.