05000333/LER-2012-003, High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line

High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line

ML12307A075
Person / Time
Site:	FitzPatrick
Issue date:	11/01/2012
From:	Michael Colomb Entergy Nuclear Operations
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
JAFP-12-0138 LER 12-003-00
Download: ML12307A075 (5)

LER-2012-003, High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x)
3332012003R00 - NRC Website

text

Entergy Nuclear Northeast

~ Inc.

P.O. Box 110 Lycoming, NY 13093 Tel 315-349-6024 Fax 315-349-6480 Michael J. Colomb November 1, 2012 Site Vice President - JAF JAFP-1 2-0138 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001

SUBJECT:

LER: 2012-003, High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 License No. DPR-59

Dear Sir or Madam:

This report is submitted in accordance with 10 CFR 50.73(a)(2)(v)(D), Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.

There are no commitments contained in this report.

Questions concerning this report may be addressed to Mr. Chris Adner, Licensing Manager, at (315) 349-6766.

Si ly, Michael J. Colomb 4w,1IC_

Site Vice President MC/CAIjo Enclosure(s):

JAF LER 2012-003, High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line cc:

USNRC, Region 1 USNRC, Project Directorate USNRC Resident Inspector INPO Records Center (ICES)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects.resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME James A. FitzPatrick Nuclear Power Plant

2. DOCKET NUMBER 05000333

3. PAGE 1 OF 4

4. TITLE High Pressure Coolant Injection System Inoperable Due to Air in Flow Element Sensing Line

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO MONTH DAY YEAR FACILITY NAME N/A DOCKET NUMBER 05000 09 02 12 2012 - 003 -

00 11 01 12 FACILITY NAME N/A DOCKET NUMBER 05000

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

9. OPERATING MODE 1

10. POWER LEVEL 100 20.2201(b) 20.2201(d) 20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(2)(v) 20.2203(a)(2)(vi) 20.2203(a)(3)(i) 20.2203(a)(3)(ii) 20.2203(a)(4) 50.36(c)(1)(i)(A) 50.36(c)(1)(ii)(A) 50.36(c)(2) 50.46(a)(3)(ii) 50.73(a)(2)(i)(A) 50.73(a)(2)(i)(B) 50.73(a)(2)(i)(C) 50.73(a)(2)(ii)(A) 50.73(a)(2)(ii)(B) 50.73(a)(2)(iii) 50.73(a)(2)(iv)(A) 50.73(a)(2)(v)(A) 50.73(a)(2)(v)(B) 50.73(a)(2)(v)(C)

X 50.73(a)(2)(v)(D) 50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(ix)(A) 50.73(a)(2)(x) 73.71(a)(4) 73.71(a)(5)

OTHER Specify in Abstract below or in BACKGROUND On August 30, 2012, the High Pressure Coolant Injection (HPCI) System [EIIS System Identifier: BJ] was declared inoperable due to the failure of HPCI booster pump P-1B recirculation pressure control valve (23PCV-

50) [EIIS Component Identifier: PCV] (See JAF LER 2012-002-00). In order to complete repairs on 23PCV-50, the HPCI suction piping had to be drained. This uncovered and drained a small section of the sensing line in the vicinity of HPCI main pump discharge flow element (23FE-80) [EIIS Component Identifier: PDI].

Following completion of these maintenance activities, the HPCI discharge piping was filled and vented in accordance with OP-15, High Pressure Coolant Injection, section G.9, Fill and Vent HPCI Suction Piping from Condensate Storage Tanks (CST). In addition, 23FE-80 sensing lines were vented by instrumentation and control (I&C) technicians in accordance with IMP-G42, Instrument Venting/Filling. This procedure vents in the downward direction from the higher elevation flow element to the lower elevation flow instrument, using the CSTs as the pressure source. No air was noted from the system vents, however, I&C technicians reported air venting from the instrument lines. At 1434 on September 2, 2012, ST-4N, HPCI Quickstart, Inservice and Transient Monitoring Test (IST), was completed satisfactory thereby demonstrating HPCI operability.

EVENT DESCRIPTION & ANALYSIS At 2257, on September 2, 2012, with the HPCI system in standby, a step change of approximately 700 gallons per minute (gpm) was noted on HPCI flow indicating controller, 23FI-108-1 with a corresponding step change of 665 gpm noted on computer point EPIC-A-1257. Under these conditions, the HPCI system would not have achieved its design flow rate while in automatic and was therefore declared inoperable. Troubleshooting, interviews, and engineering evaluation determined that the step change on the flow indicating controller and EPIC computer point was due to air in the instrument sensing lines.

As previously discussed, the instrument sensing lines were vented by I&C personnel following maintenance of 23PCV-50. Since the instrument lines were not drained during this activity, they should have remained full of water. The instrument lines were designed to have a positive slope (upwards towards the pipe), any air in the instrument line would be dispersed back up into HPCI piping. However, it was noted during walkdowns that the instrument lines were not properly sloped in the positive direction.

Any air that was pushed down during instrument line venting could have worked its way past the negatively sloped areas in the low pressure instrument sensing line, causing a differential pressure (d/p). This d/p would have been sensed by the flow transmitter and converted into a flow signal, which then would have provided indication of HPCI flow to 23FI-108-1. The signal also provides input to EPIC-A-1257 computer point. The accuracy of this loop depends on the instrument lines (both the high and low pressure) being filled with water at all times. Any air trapped in a vertical leg will result in an inaccurate flow signal.

CAUSE OF EVENT

The false flow indication was the result of air in the instrument sensing line creating a d/p across the flow element. The apparent cause for the air void is the improper sloping of the instrument sensing line. This allowed water to drain from the line during maintenance and did not allow the line to self vent when the HPCI suction piping was filled. U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET

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James A. FitzPatrick Nuclear Power Plant 05000333 2012 -

003 00 3 OF 4 A contributor to this event was inadequate procedural guidance for filling and venting the instrument sensing lines. IMP-G42 directs the technician to perform a forward flush by opening the lowest point drain valves, and then use CST water as the pressure source to vent the sensing line to the low point drain. This method of venting can push air bubbles down into the horizontal elevations of the sensing lines where it will not initially impact the instrument reading. After time, the air bubbles can migrate up into the vertical sensing line and become trapped. The trapped air would displace the water in this vertical section of piping creating a d/p across the flow element thus giving a false indication of flow.

EXTENT OF CONDITION The extent of condition for this event reviewed CR-JAF-2001-00308 evaluation and corrective actions. It was determined that this evaluation was extensive and thorough. It was identified that the reactor core isolation cooling (RCIC) system [EIIS System Identifier: BN] instrumentation is most similar in configuration. Therefore, the extent of condition corrective action is limited to walking down the RCIC flow instrument tubing.

CORRECTIVE ACTIONS

Completed Revised IMP-G42 to provide instructions to perform a pressurized back flush.

Performed multiple fill and vent cycles of the instrument sensing line.

Verified operability of the HPCI system by satisfactory performance of ST-4N.

Operators periodically monitor the flow indicator-controller in the control room. No deviations have been identified.

Future Actions Perform an evaluation to determine best approach to correct this condition long term; options include relocating the instrument to be adjacent to the flow element or re-slope the instrument sensing lines in accordance with existing design requirements.

Evaluate the effectiveness of the revised IMP-G42.

ASSESSMENT OF SAFETY CONSEQUENCES

Radiological & Industrial Safety There were no actual or potential radiological or industrial safety consequences as a result of this condition.

Nuclear Safety There was no actual nuclear safety consequences associated with this condition. The potential nuclear safety consequences are considered minimal because during this period of HPCI inoperability, the Automatic Depressurization System (ADS), CS, and Low Pressure Coolant Injection (LPCI) systems [EIIS System Identifier: BO] were operable. The ADS in combination with the LPCI and CS systems would ensure adequate core cooling is maintained in the event of HPCI inoperability. Also, even though the RCIC system is not credited for accident analysis, it would have automatically provided makeup water at most reactor operating pressures. U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET

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James A. FitzPatrick Nuclear Power Plant 05000333 2012 -

003 00 4 OF 4 SIMILAR EVENTS Internal operating experience (OE) was reviewed for similar events relevant to the condition described in this LER. In 2010 during refueling outage 19, a similar event occurred where the HPCI flow indicator-controller indicated 1300 gpm with the system in standby. The corrective action was to vent the instrument and instrument sensing lines. In 2001 two events occurred in which the HPCI flow indicator-controller indicated flow with the system in standby.

The analysis performed in 2001 determined that the incorrect flow indication was caused by trapped air in the instrument sensing lines. Inconsistencies were discovered when the sensing lines were inspected for proper slope. Portions of the line were identified to have negative slope and air would be trapped in the line when the system was drained and refilled. Corrective actions were developed to re-slope the lines, but were ineffective.

External OE was reviewed on the Institute of Nuclear Power Operations (INPO) website. Two examples were found where plants identified incorrect slope on instrument tubing. This resulted in air causing an offset between the instrument readings and the actual parameter. In one example the offset was evaluated to have minimal impact on instrument setpoint or indications. In the second example, maintenance procedures were updated to vent the lines as they were identified.

REFERENCES JAF Condition Reports: CR-JAF-2012-05068, CR-JAF-2010-07095, CR-JAF-2001-00308, CR-JAF-2001-00328 JAF TS 3.5.1, ECCS - Operating JAF FSAR 6.4.1 High Pressure Coolant Injection System