05000272/LER-2010-003
| Salem Generating Station - Unit 1 | |
| Event date: | |
|---|---|
| Report date: | |
| 2722010003R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
Westinghouse — Pressurized Water Reactor (PWR/4) Auxiliary Feedwater System {BN-} * Energy Industry Identification System {EIIS} codes and component function identifier codes appear as {SS/CCC}
IDENTIFICATION OF OCCURRENCE
Event Date: July 23, 2010 Discovery Date: July 25, 2010
CONDITIONS PRIOR TO OCCURRENCE
Salem Unit 1 was in Mode 1 at approximately 99.7% reactor power when the disabled start circuitry was identified. There was no other equipment out of service that contributed to this event.
DESCRIPTION OF OCCURRENCE
On July 25, 2010, at 0940 hours0.0109 days <br />0.261 hours <br />0.00155 weeks <br />3.5767e-4 months <br />, an Instrument and Control (I&C) Technician identified the circuitry was disabled for the motor driven auxiliary feedwater (AFW) pump automatic start on a trip of both steam generator feedwater pumps (SGFPs). At the time of discovery Salem Unit 1 was in Mode 1. The AFW automatic start circuitry is required by Technical Specification (TS) 3.3.2.1 function 8f to be operable in Modes 1 and 2. The operating shift entered TS Action Statement (TSAS) 3.3.2.1 action 21 for function 8f. Action 21 states that, "with the number of OPERABLE channels one less than the Minimum Number of Channels, operation may proceed provided that the inoperable channel is restored to OPERABLE with 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />." TSAS action 21 entry was considered applicable when Salem Unit 1 entered Mode 2 on July 23, 2010, at 2152 hours0.0249 days <br />0.598 hours <br />0.00356 weeks <br />8.18836e-4 months <br />. At 1557 hours0.018 days <br />0.433 hours <br />0.00257 weeks <br />5.924385e-4 months <br /> on July 25, 2010, the automatic start of the AFW pumps on a trip of both SGFPs was re-established and TSAS 3.3.2.1 action 21 was exited. Entry into Mode 2 with the circuitry required by TS 3.3.2.1 function 8f disabled was a condition prohibited by Technical Specification 3.0.4.
This report is made in accordance with 10CFR50.73 (a)(2)(i)(B), "any operation or condition which was prohibited by the plant's Technical Specifications.
�NRC FORM 366 (9-2007) PRINTED ON RECYCLED PAPER
CAUSE OF OCCURRENCE
The cause of the failure to re-establish the automatic start circuitry for the start of the motor driven AFW pumps on a trip of the SGFPs was due to operators performing the incorrect section of procedure S1.0P SO.RPS-0009 to re-establish the start circuitry during mode ascension. The guidance in the mode ascension integrated operating procedures did not indicate which section of procedure S1.0P-SO.RPS 0009, "Installation/Removal of AFW Start Function from SGFP Trips," to implement to re-establish the start circuitry. The operators performing the evolution assumed that the 'Aux Feed Auto Start Enabled' control console bezel light indicated that all AFW start functions were established; however, when section 5.2 of procedure S1.0P-SO.RPS-0009 is implemented to disable the start function based on loss of the SGFPs the bezel light indication continues to remain lit with the function disabled. The operators performed section 5.1 of procedure S1.0P-SO.RPS-0009 which led them to believe that the AFW start function had been re-established.
PREVIOUS OCCURRENCES
changing from Mode 5 to Mode 4. The apparent cause of this event was the lack of formal independent verification to ensure TS requirements are met prior to mode changes. The corrective actions associated with this event were specific to the previous event and would not have prevented the current event from occurring.
SAFETY CONSEQUENCES AND IMPLICATIONS
There were no safety consequences associated with this event. Although the start of the motor driven AFW pumps on a trip of the SGFPs was disabled during operation in Modes 1 and 2, upon loss of both SGFPs the motor driven AFW pumps would have started on low-low level in the steam generators. As discussed in Salem UFSAR section 15.2.8 for a 'Loss of Normal Feedwater' event, the USFAR states that the two motor-driven auxiliary feedwater pumps are assumed available eighty five seconds after receipt of the low-low steam generator water level reactor trip signal. This capability was maintained with the ability to automatically start the motor driven AFW pumps on receipt of a low-low steam generator level signal.
A review of this event determined that a Safety System Functional Failure (SSFF) as defined in NEI 99-02, Regulatory Assessment Performance Indicator Guidelines, did not occur since the ability to remove residual heat and mitigate the consequences of an accident were maintained.
CORRECTIVE ACTIONS
1. Integrated operating procedures S1(2)0P-10.ZZ-0002, "Cold Shutdown to Hot Standby," will be revised to specify the section of procedure S1(2).OP-SO.RPS-0009, "Installation/Removal of AFW Start Function From SGFP Trips," to use to restore the AFW start circuitry and to include an independent verification that the automatic start function is restored.
2. Procedures S1(2).OP-SO.RPS-0009 will be revised to improve clarity and establish additional barriers when lifting and landing leads associated with the AFW automatic start function on a trip of SGFPs.
3. The simulator guide for training on S1(2)OP-IO.ZZ-0002 was revised to include a discussion of this event and clarify operation of the AFW automatic start circuitry on a trip of .SGFPs.
4. Personnel involved with this event will be held accountable in accordance with PSEG policies.
COMMITMENTS
No commitments are made in this LER.