05000255/FIN-2015001-03
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Finding | |
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| Title | Turbine-Driven AFW Pump Trip During Surveillance Testing |
| Description | On November 14, 2014, during performance of surveillance procedure RO-127, the turbine-driven AFW pump overspeed trip mechanism actuated and tripped the pump, which resulted in entry into 72-hour TS LCO 3.7.5 Condition A. Personnel performing the test reported no abnormalities prior to the trip. The pump had been operated satisfactorily on November 13, 2014, during performance of quarterly surveillance procedure QO-21, Inservice Test ProcedureAuxiliary Feedwater Pumps, Revision 43. Following the November 14 pump trip, the licensee performed a sequence of testing in an attempt to replicate the overspeed trip to assist in cause identification, or to demonstrate operability if the trip could not be replicated. This sequence included test runs in accordance with procedure SOP12, Feedwater System, Revision 72; procedure RO145, Comprehensive Pump Test Procedure, Auxiliary Feedwater Pumps P8A, P8B and P8C, Revision 13; and a modified test run in accordance with procedure T186, Auxiliary Feedwater Turbine K8 Overspeed Trip Test and Governor Setting, Revision 18. Since all acceptance criteria were met, the licensee declared the turbine-driven AFW pump operable on November 16, 2014, and LCO 3.7.5 was exited. The licensee subsequently conducted an ACE that identified three possible causes: 1) excess condensate in the moisture removal system, 2) decreased margin between the as-found operating speed and the overspeed trip setpoint, and 3) inherent design conditions of the steam supply and steam control system affecting the speed of the turbine. The evaluation also identified discrepancies in the Maintenance Rule classification of the steam traps and the frequency of preventive maintenance activities that were conducted on the equipment. Corrective actions were generated to evaluate each of the possible causes during the next pump maintenance outage, which occurred from March 26, 2015. The licensee conducted procedure T186 to verify the overspeed trip mechanism would trip within its required band and that the governor was functioning properly to changes in steam supply and pump speed. Procedure RO145 was conducted to observe steam trap operation and any oscillations in the steam supply system. Finally, the overspeed trip setpoint was revised based on the vendors recommendation for the operating conditions of this particular pump. At the end of the inspection period, all of the data from these tests were under review by the licensee, with vendor support, to aid in determining the cause of the November 2014 pump trip. Pending inspector review of the licensees data, conclusions, and any revisions made to the ACE, this issue is unresolved. |
| Site: | Palisades  |
|---|---|
| Report | IR 05000255/2015001 Section 1R12 |
| Date counted | Mar 31, 2015 (2015Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | J Cassidy J Lennartz M Phalen R Elliott R Walton A Garmoe A Scarbeary E Duncana Armstronga Nguyen C Hunt G Hansen G O'Dwyer J Boettcher J Cassidy J Coroju-Sandin J Jandovitz J Lennartz J Rutkowski L Rodriguez M Domke M Holmberg M Keefe T Taylor V Myers |
| INPO aspect | |
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Finding - Palisades - IR 05000255/2015001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Palisades) @ 2015Q1
Self-Identified List (Palisades)
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