05000339/LER-2004-003
| Document Number | |
| Event date: | 0-6-2004 |
|---|---|
| Report date: | 0-8-2004 |
| 3392004003R00 - NRC Website | |
FACILITY NAME (1) DOCKET 1 NUMBER NUMBER LER NUMBER 6) PAGE (3) 1.0 DESCRIPTION OF THE EVENT On May 28, 2004, at 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> with Unit 2 in Mode 5, containment personnel air lock (EIIS System - NH, Component - AL) leakage testing was performed as part of the start up activities following a refueling outage. Both the inner and outer containment personnel air locks tested satisfactorily. Unit 2 entered Mode 4 at 0838 hours0.0097 days <br />0.233 hours <br />0.00139 weeks <br />3.18859e-4 months <br /> on May 28, 2004. On June 3, 2004, at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> the containment personnel air lock leakage testing was performed satisfactorily following several containment entries. On June 6, 2004, at 1605 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.107025e-4 months <br /> leakage was noted on the outer containment personnel air lock during testing.
The "close" push button was depressed and the locking ring traveled approximately three inches to the full locked position. Subsequently, with the locking ring in the full closed position leakage test was performed with satisfactory results.
The air lock was declared inoperable at 1605 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.107025e-4 months <br /> on June 6, 2004, and Technical Specification (TS) actions were entered at that time. Satisfactory testing was completed within the required times. However, after further review it was determined that the outer containment personnel air lock was inoperable since the last containment entry prior to the June 6, 2004 test. The last entry occurred on June 4, 2004 at 1348 hours0.0156 days <br />0.374 hours <br />0.00223 weeks <br />5.12914e-4 months <br />. As a result, the TS actions were missed to verify within one hour the operable door is closed and lock the operable door closed within twenty four hours. A missed surveillance occurred which is a condition prohibited by TS.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS This event posed no significant safety implications since the inner containment personnel air lock was sealed, the containment was operating under vacuum and no leakage escaped to the atmosphere. 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 that is prohibited by the Technical Specifications.
3.0 CAUSE The cause of this event is attributed to interface design. The containment personnel air lock full locked position is not easily discernable because there are no indications showing a locked position (i.e., match marks or visual clues) for the locking ring and the operating procedure does not describe the details of the locked position. Utility personnel operating the outer containment personnel air lock door upon exiting containment on June 4, 2004, did not ensure the locking ring was in the locked position. The function of opening and closing the containment personnel air lock doors was considered skill of the FACILITY NAME (1) DOCKET LER NUMBER 6) PAGE (3) 3.0 CAUSE (continued) craft and as such, the procedure is not required to be in hand. Operating the containment personnel air lock while the plant is in operation is an infrequent evolution and does not have an independent verification of the activity.
4.0 IMMEDIATE CORRECTIVE ACTION(S) Upon discovery of the leakage during testing the "close" push button for the air lock door was depressed and the locking ring moved approximately three inches to the "locked" position. Subsequent leak testing was completed satisfactorily. A station deviation report was initiated.
5.0 ADDITIONAL CORRECTIVE ACTIONS Procedure enhancements are being made including requiring the use of the procedure any time the containment personnel air lock is operated following entry in to Mode 4 or above and an independent verification of such. Improved labeling is being instituted to upgrade identification of all controls and indications on both the interior and exterior containment personnel air lock doors for both units.
6.0 ACTIONS TO PREVENT RECURRENCE Actions as presented are sufficient to preclude recurrence.
7.0 SIMILAR EVENTS None 8.0 ADDITIONAL INFORMATION At the time of this event North Anna Unit 1 was operating at 100 percent power and was not affected by this event.