05000348/LER-2004-002
| Joseph M. Farley Nuclear Plant - Unit 1 | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3482004002R00 - NRC Website | |
Westinghouse -- Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX]
Description of Event
On November 5, 2004, at 0911, with the reactor in Mode 6, Unit 1 experienced a B Train Loss of Site Power (LOSP) due to inadvertent actuation of B Train bus undervoltage relays [EB] during surveillance testing. Establishment of initial conditions for performance of the B Train LOSP, Load Shedding, and Station Black Out (SBO) Diesel Generator (DG)[EK] Start Test (STP 80.15) was in progress. Jumpers were installed for performance of this test that allowed the 27XG and 2G relays to energize with the sequencer in test mode. Relay 27XG actuates the Load Shed relays and provides the start signal to the 1B DG. Relay 2G removes the Load Shed and DG start signal from relay 27XG after 2 seconds has elapsed.
At the same time as these test preparations were in progress, the monthly Degraded Grid Voltage and Loss of Voltage Protection Relays Operability Test (STP 80.16) was due. This monthly test was not in the outage schedule. This relay functional test is intended to be performed with the sequencer in test mode, in which the 27XG and 2G relays are de-energized. This monthly test normally does not actuate any Engineered Safety Feature (ESF) equipment.
Operations Shift Supervision concurred with performance of STP-80.16 along with the continued preparations for the performance of STP-80.15, and did not realize the incompatibility of these two tests.
Depressing the test pushbuttons in accordance with the monthly undervoltage relay operability test (STP 80.16) caused an undervoltage condition to be detected by the sequencer relays. Since the jumpers were installed for the performance of the B Train LOSP Test (STP 80.15), these relays were energized and therefore initiated the load shed and 1B DG start sequence.
By design, the LOSP sequencers do not start the Residual Heat Removal (RHR)[BP] pumps. Therefore, the LOSP caused a loss of the previously running 1B RHR pump. The operating crew immediately restored shutdown cooling by starting the lA RHR pump, in accordance with Abnormal Operating Procedures, in less than one minute. All actions of the Abnormal Operating Procedure for loss of shutdown cooling were completed by 0926. Offsite power was restored to the B Train safeguards busses at 0959, and the 1B DG was subsequently shut down.
Additionally, the 1B Motor Driven Auxiliary Feed Water (MDAFW)[BA] pump, which had not undergone post maintenance testing following overhaul, started as designed, but tripped on overcurrent.
All other equipment operated as designed following the LOSP and sequencer operation.
Cause of Event
This event was caused by inadequate work scheduling and procedures. Additionally, Operations Shift Supervision did not make themselves fully aware of the conditions previously established for the performance of STP- 80.15 and did not realize the incompatibility of these two tests.
Safety Assessment The health and safety of the public were unaffected by this event.
Since the B Train LOSP, Load Shedding, and SBO DG Start Test (STP 80.15) is only conducted during refueling outages, this event does not represent an at power concern.
The 1B MDAFW pump trip occurred in a mode in which the pump was not required, prior to post maintenance testing, and therefore has no safety significance.
This event does not represent a Safety System Functional Failure since the opposite train of all required equipment was operable throughout the event.
Corrective Action The Unit 1 and Unit 2, A Train and B Train LOSP, Load Shedding, and DG Start Test procedures (4 procedures) have been revised to caution tag the sequencer test switch when jumpers are installed adding amplifying information to clarify the function of the jumpers and to increase operators' awareness. In addition, the pre-job briefing template for this activity has been revised to include this operating experience and purpose of the test jumper.
Outage management procedures will be changed to require a review of all non-outage surveillances coming due during an outage and to assess their impact on outage plant configuration, by May 31, 2005.
A Training Notice will be sent to licensed personnel explaining the event sequence, root causes, and actions to prevent recurrence, by January 30, 2005.
Applicable training committees will review this event for potential inclusion in additional training, by May 31, 2005.
Following troubleshooting and repair, the 1B MDAFW pump was tested satisfactorily and returned to service.
Additional Information
As an enhancement already planned prior to this event, the daily surveillance schedule will be incorporated into the integrated work planning schedule by May 1, 2005.
The 1B MDAFW pump is not being reported as a failure in this LER since it had not been returned to service following maintenance activities.
The following LER has been submitted in the past two years concerning unplanned ESF actuations other than reactor trips:
Feed Pump.