05000311/LER-2016-001, Regarding AFW Loop Response Time Exceeded Technical Specifications
| ML16081A369 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 03/21/2016 |
| From: | Carr E Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N16-0068 LER 16-001-00 | |
| Download: ML16081A369 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3112016001R00 - NRC Website | |
text
PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, NJ 08038-0236 March 21, 2016 LR-N 16-0068 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 10 CFR 50.73 Salem Nuclear Generating Station Unit 2 Renewed Facility Operating License No. DPR-75 NRC Docket No. 50-311
SUBJECT:
LER 311/2016-001 AFW Loop Response Time Exceeded Technical Specifications Licensee Event Report, "AFW Loop Response Time Exceeded Technical Specifications" is being submitted pursuant to 10 CFR 50.73 (a)(2)(i)(B), "Any operation or condition which was prohibited by the plant's Technical Specification."
Should you have any questions or comments regarding the submittal, please contact Mr. Thomas Cachaza of Regulatory Affairs at 856-339-5038.
There are no regulatory commitments contained in this letter.
Sincerely, Eric Carr Plant Manager Salem Generating Station pjd Enclosure-LER 311/2016-001-00
Page 2 LR-N 16-0068 cc 10 CFR 50.73 Mr. D. Dorman, Administrator-Region 1, NRC Mr. T. Wengert, Licensing Project Manager-Salem, NRC Mr. P. Finney, USNRC Senior Resident Inspector, Salem (X24)
Mr. R. Braun, President and Chief Nuclear Officer-Nuclear Mr. T. Cachaza, Salem Commitment Tracking Coordinator Mr. L. Marabella, Corporate Commitment Tracking Coordinator
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 (02-2014)
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, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 6. LER NUMBER YEAR I SEQUENTIAL I REV ISION NUMBER NUMBER 2016
- - 001
- - 000
- 3. PAGE 2 OF4 Auxiliary Feedwater System/Pump Flow Control Valves {BA/FCV)
- Energy Industry Identification System (EllS) codes and component function identifier codes appear as
{SS/CCC}.
IDENTIFICATION OF OCCURRENCE Event Date: 04/20/2015 Discovery Date: 01/19/2016 CONDITIONS PRIOR TO OCCURRENCE Salem Unit 2 was in Mode 1 at 100 percent rated thermal power (RTP).
DESCRIPTION OF OCCURRRENCE On January 19, 2016, while reviewing outage data, plant staff recognized that anomalous data collected in October 2015, for the 21 Auxiliary Feed Pump time response loop resulted in failure to meet a surveillance, rendering that channel of Auxiliary Feedwater automatic actuation inoperable. In November 2015, the isolation valve for the pressure override defeat pressure transmitter was found closed. The pressure transmitter provides an input into the 21 AFW Pump run-out protection circuit. With the isolation valve closed, it would take longer to sense pump discharge head and consequently the opening of the auxiliary feed pump flow control valves {BA/FCV} would be slower than normal. The AFW flow control valves will not open until adequate pump discharge head is sensed by the pressure transmitter.
This condition resulted in 21 Auxiliary Feedwater Pump loop time response greater than Technical Specification (TS) acceptance criteria. The failed channel was not recognized and the TS action was not taken, resulting in a condition prohibited by TS. The investigation revealed that the condition most likely existed since April 20, 2015, when maintenance activities were performed on the auxiliary feedwater pump discharge pressure transmitter. This condition resulted in 21 Auxiliary Feedwater Pump loop time response greater than the acceptance criteria required by surveillance 4.3.2.1.3. The isolation valve was opened and the surveillance was performed satisfactorily.
Timeline 04/20/15 10/18/15 11/18/15 11/20/15 01/19/16 2PA3450, 21 Auxiliary Feed Pump Discharge Pressure Transmitter, calibration done Operations performed time response testing on 21 Auxiliary Feedwater (AFW) loop I&C technicians documented unsatisfactory time response for 21 AFW loop Instrument isolation valve for 2PA3450 found closed Plant staff review of outage data identified failed surveillance and need to review condition for reportability U.S. NUCLEAR REGULATORY COMMISSION (02-2014)
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LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET Salem Generating Station - Unit 2 05000311 APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 6. LER NUMBER YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 2016
- - 001
- - 000
- 3. PAGE 3 OF4 Operations began time response testing in advance of the scheduled refueling outage while still in MODE 1. When 21 AFW loop was tested, the long response time of the flow control valves for the two loops associated with the pump were noticed, but not documented or investigated for impact on operability.
When I&C began to collate time response data from the outage testing, they recognized the failure to meet the acceptance criteria for 21 AFW loop time response. The isolation valve for the discharge pressure transmitter was found closed. The isolation valve was opened, and the loop response time testing was completed with satisfactory results.
The investigation for the mispositioned pressure transmitter isolation valve did not definitively conclude that the maintenance activities of April 20, 2015, created the condition, but no other procedures operate the isolation valve. All other AFW surveillances were completed satisfactorily during the period from April through October. The dynamic system response and the pressure override function are only tested by the time response surveillance ; the other AFW surveillances would not reveal the mispositioned pressure transmitter isolation valve.
The impact of the mispositioned valve was not recognized until a review of outage data was performed on January 19, 2016.
This event is being recorded in accordance with 1 OCFR50. 73 (a)(2)(i)(B), "Any operation or condition which was prohibited by the plant's Technical Specifications."
CAUSE OF EVENT
The most likely cause of this event was the failure to return the auxiliary feedwater pump discharge pressure transmitter instrument isolation valve to the open position following transmitter calibration.
SAFETY CONSEQUENCES AND IMPLICATIONS
The Auxiliary Feedwater (AFW) System serves as a backup system for supplying feedwater to the secondary side of the steam generators at times when the Main Feedwater System is not available. The AFW System is relied upon to prevent core damage and system overpressurization.
An engineering review concluded that while the AFW loop response time test results did not meet the procedural acceptance criteria, the accident analysis assumptions remained valid. The A TWS (Anticipated Transient Without Scram) was determined to be the limiting accident, and the loop response times were still bounded by the existing analyses. There were no safety consequences as a result of this event. U.S. NUCLEAR REGULATORY COMMISSION (02-2014) t<lf!'"""'"'*'f..
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"'1***W""'l LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET Salem Generating Station - Unit 2 05000311 SAFETY SYSTEM FUNCTIONAL FAILURE APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 6. LER NUMBER I
SEQUENTIAL NUMBER YEAR 2016
- - 001 I REVISION NUMBER
- - 000
- 3. PAGE 4 OF4 This condition did not result a safety system functional failure as defined in NEI 99-02, Regulatory Assessment Performance Indicator Guidelines.
PREVIOUS EVENTS A review of previous events for the past three years identified no similar events.
CORRECTIVE ACTIONS
The pressure transmitter isolation valve was re-opened and the time response surveillance for 21 Auxiliary Pump flow control was performed with satisfactory results.
COMMITMENTS
There are no regulatory commitments contained in this LER.