05000280/LER-2002-001

LER-2002-001,

Document Number
Event date:	12-31-2002
Report date:	03-03-2003
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation
2802002001R00 - NRC Website

FACILITY NAME (1)

DOCKET

05000 - 280 LER NUMBER (6) PAGE (3) 2 � OF4 1.0 DESCRIPTION OF THE EVENT On December 31, 2002 at 08:10 hours, a Reactor Protection System Logic monthly Periodic Test (PT) of Train "A" was commenced. During performance of the PT, utility Maintenance Technicians in the Relay Room discovered a failed relay and notified Operators at 09:18 hours. The relay was the Train "A" Motor Driven Auxiliary Feedwater Pump (MDAFWP) starting relay [EIIS-JC, 3]. The Train "A" MDAFWP automatically started with reactor power at 100%. The Operators placed the Train "A" MDAFWP control switch in pull-to-lock, and started a 72-hour action statement in accordance with the Technical Specification (TS) requirement that two motor driven auxiliary feedwater pumps be operable. The Operators also started a 24-hour action statement in accordance with the TS requirement for a minimum of two operable AFW automatic actuation logic channels. The Train "A" MDAFWP automatic start is a reportable condition per 10 CFR 50.73(a)(2)(iv).

At 18:09 hours, as the failed relay was being removed from the relay cabinet, the Steam Driven Auxiliary Feedwater Pump (SDAFWP) automatically started. At 18:23 hours, Operations secured the SDAFWP and returned it to automatic. Relay replacement recommenced, and at 18:31 hours the SDAFWP automatically started for the second time. At 18:33 hours, Operators again secured the SDAFWP. The two automatic starts of the SDAFWP that occurred during relay replacement are reportable under 10 CFR 50.73(a)(2)(iv). In both SDAFWP automatic starts a temporary jumper lost continuity due to intermittent contact by the jumper's alligator clip. The jumper was held in place while the failed relay was replaced. At 19:52 hours, Maintenance Technicians replaced Train "A" MDAFWP starting relay and removed the jumper. At 20:10 hours, Maintenance Technicians completed post-maintenance testing requirements for Train "A" MDAFWP starting relay replacement, Operators stopped the 24-hour action statement, and the Reactor Protection System Logic monthly PT on Train "A" was recommenced. At 20:12 hours, Operators placed Train "A" MDAFWP in automatic, and stopped the 72-hour action statement. At 20:21 hours, the monthly PT on Train "A" was completed satisfactorily. The elapsed time from the discovery of the relay failure until the train was returned to service was 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> and 3 minutes.

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS When the Train "A" MDAFWP starting relay failed, it de-energized to provide its safety function and a start signal was initiated to Train "A" MDAFWP. This actuation resulted from an invalid signal due to the relay failure. The actuation initiated auxiliary feed flow that was in addition to the normal feed flow from the two main Feedwater Pumps. The auxiliary feed flow was not required and was promptly terminated. The two main Feedwater pumps, the SDAFWP, the redundant "B" AFW train, and the cross-connect from Unit 2 AFW system remained operable. The last time the Train "A" MDAFWP starting relay was demonstrated to be capable of performing its safety function was when the relay cycled earlier in the PT performed on December 31, 2002.

During the Train "A" MDAFWP starting relay replacement, the SDAFWP automatically started twice due to a failure of a temporary jumper to keep the SDAFWP starting relay energized. The jumper had been placed at the correct electrical point, but intermittent contact by the jumper's alligator clip during the replacement caused the SDAFWP starting relay to de-energize and re-energize thus causing the pump starts. The automatic starts initiated auxiliary feed flow in addition to the normal feed flow from the two main Feedwater Pumps. The auxiliary feed flow was not required, and was terminated. The function of the SDAFWP starting relay was not lost. The two main Feedwater Pumps, the redundant "B" AFW train, and the cross-connect from Unit 2 AFW system remained operable.

There were no other structures, systems, or components that were inoperable at the start of the event and contributed to the event.

As a result, the related safety function remained operable, and the health and safety of the public was not jeopardized.

3.0 CAUSE The cause of Train "A" MDAFWP starting relay invalid actuation was end of life coil failure. The Train "A" MDAFWP starting relay was installed in 1985.

The cause of the two automatic starts during Train "A" MDAFWP starting relay replacement was intermittent contact by a temporary jumper's alligator clip. The jumper was placed at the correct electrical point but intermittent contact by the jumper's alligator clip during the replacement caused the SDAFWP starting relay to de-energize and re- energize thus causing the pump starts.

4.0 IMMEDIATE CORRECTIVE ACTION(S) As described above, for each inadvertent start, AFW flow was subsequently terminated, and related TS action statements were entered as required.

5.0 ADDITIONAL CORRECTIVE ACTIONS The temporary jumper was held in place to prevent intermittent contact until the failed Train "A" MDAFWP starting relay was replaced and post maintenance testing was completed. Then the Reactor Protection System Logic monthly Periodic Test of Train "A" was completed satisfactorily, and the Train "A" AFW was declared operable at 20:21 hours.

6.0 ACTIONS TO PREVENT RECURRENCE Evaluations are in progress to determine the causes of these events. The approved recommendations from these evaluations will be implemented.

7.0 SIMILAR EVENTS On December 14, 2002 while performing a different PT, a temporarily installed jumper alligator clip failed to establish continuity due to a high resistance connection. The cause of the high resistance was attributed to oxidation on the terminal screw to which the jumper's alligator clip was attached. The jumper's alligator clip was removed from the terminal point screw, the jumper's alligator clip was reconnected to the wire landed on the terminal point, and the PT was performed satisfactorily.

8.0 MANUFACTURER/MODEL NUMBER The failed Train "A" MDAFWP starting relay was a Westinghouse model BFD-24S.

9.0 ADDITIONAL INFORMATION None.