ML20029D632

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LER 94-002-01:on 940115,centrifugal Charging Pump 1A Discharge Bypass Valve Found in Open Position Contrary to Requirements of TS 3.1.2.3.Caused by hydro-pneumatic Transient.Valves Labeled W/Caution statements.W/940502 Ltr
ML20029D632
Person / Time
Site: South Texas STP Nuclear Operating Company icon.png
Issue date: 05/02/1994
From: Groth J, Pinzon J
HOUSTON LIGHTING & POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-002, LER-94-2, ST-HL-AE-4781, NUDOCS 9405090113
Download: ML20029D632 (6)
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The Light companySu llouston Lighting & Power ex as l'rojeu cu c Generadng tadon l' . Hos289 Wadsworth, Texas 77183 May 2, 1994 ST-IIL-AE-4781 File No.: G26 10CFR50.73 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Unit 1 Docket No. STN 50-498 Revision I to Licensee Event Report 94-002 Centrifugal Charging Pump 1 A Discharge Bypass Valve in the Open Position Contrary to the Reauirements of Technical Specification 3.1.2.3 Pursuant to 10CFR50.73, Houston Lighting & Power submits the attached Revision to Unit 1 Licensee Event Report 94-002 regarding the Centrifugal Charging Pump 1A discharge bypass valve being found in the open position contrary to the requirements of Technical Specification 3.1.2.3. This event did not have an adverse effect on the health and safety of the  :

public but clearly does not meet the standards for expected operational performance. 1 This revision clarifies inconsistencies that have been identified in the LER which may lead to some misunderstanding These changes do not change the intent of the LER. Changes are indicated by revision bars.

If you should have any questions on this matter, please contact Mr. J. M. Pinzon at (512) 972-8027 or me at (512) 972-8664.

-w J. F. oth Vice President, Nuclear Generation MAClesh

Attachment:

Revision 1 to LER 94-002 (South Texas, Unit 1) 9405090113 940502 PDR ADOCK 05000498 i S PDR , Subidim of liouuon Industries incorpor.ned L94 00? R 1, Ui

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Houston Lighting & Power Company ST-HL-AE-4781 South Texas Project Electric Generating Station File No.: G26 i

1 Page: 2 c:

Leonard J. Callan Rufus S. Scott l Regional Administrator, Region IV Associate General Counsel l U. S. Nuclear Regulatory Commission Houston Lighting & Power Company 611 Ryan Plaza Drive, Suite 400 P. O. Box 61067 Arlington, TX 76011 Houston, TX 77208 Lawrence E. Kokajko Institute of Nuclear Power l

Project Manager Operations - Records Center l l U. S. Nuclear Regulatory Commission 700 Galleria Parkway l l Washington, DC 20555-0001 13H15 Atlanta, GA 30339-5957  ;

1 David P. Loveless Dr. Joseph M. Hendrie

, Sr. Resident Inspector 50 Bellport Lane I

c/o U. S. Nuclear Regulatory Comm. Bellport, NY 11713 P. O. Box 910 Bay City, TX 77404-910 D. K. Lacker Bureau of Radiation Control ,

J. R. Newman, Esquire Texas Department of Health I Newman, Bouknight & Edgar, P.C. 1100 West 49th Street STE 1000, 1615 L Street, N.W. Austin, TX 78756-3189 Washington, DC 20036 U. S. Nuclear Regulatory Comm.

K. J. Fiedler/M. T. Hardt Attn: Document Control Desk City Public Service Washington, D. C. 20555-0001 P. O. Box 1771 San Antonio, TX 78296 J. C. Lanier/M. B. Lee City of Austin Electric Utility Department ,

721 Barton Springs Road 1 Austin, TX 78704 ,

G. E. Vaughn/C. A. Johnson Central Power and Light Company l P. O. Box 2121 l Corpus Christi, TX 78403 I

1 l

1

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB N0. 3150 0104 (5 92) , EXPIRES 5/31/95 i l'

. ESilMATED BURDEN PER RESPONSE TO COMPLY W!iH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

i LICENSEE EVENT REPORT (LER) FORWARD COMMENTS REGARDING BURDEN EST! MATE TO l

THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MN88 7714), U.S. NUCLEAR REGULATORY COMMISSION, (See reverse for required number of digits / characters for each block) WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK  ;

REDUCTION PROJECT (3150 0104), OFFICE OF )

MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

IACILITY NAME (1) DOCKET NUMBLR (2) PAGE (3)

South Texas Unit 1 05000 498 1 OF 4 TITLE (4) Centrifugal Charging Pump 1 A Discharge llypass Valve lleing Found in the Open Position Contrary to the I

i Requirements of Technical Specifications 31.23 I EVENT DATE (5) LER NUMBER (6) REPORT DA1E (7) 01HER F AClllilES INVOLVED (8) l FACilliY NAME DUCFET NUMBER SEQUENTIAL REVISION MONTH DAY YEAR YEAR NUMBER NUMBER M NTH DAY YEAR 05000 l 01 15 94 94 --

002 -- 01 05 02 94 ' f07f0 0

OPERATING THIS REPORT IS SUBMITTED PURSUANT TO lHE REQUIREMENTS OF 10 CFR O (Check one or more) (11) 5 H0DE (9) 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73. 71( b)

POWER .4 5(a)(1)(i) 5 .36(c)(1) 50.73(a)(2)(v) 73.71(c) 0 LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50. 73(a)(2 )(vi i ) OTHER 50.73(a)(2)(viii)(A) Wy = Abw W ud 20.405(a)(1)(iii) X 50.73(a)(2)(i) * * ""

20.405(a)(1)(iv) 50.73(a)(2)( i i ) 50.73(a)(2)(viii)(B) 20.405(a)(1)(v) 50. 73(a)(2 )( t i l ) 50.73(a)(2)(x)

LICENSEE CONTACI FOR 1HIS lER (12)

NAME TELEPHONE NUMBER (include Area Code)

Jairo Pinzon - Staff Engineer (512) 972-8027 COMPLETE ONE llNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER

[

SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR YES(if yes, complete EXPECTED SUBMISSION DATE). X NO DATE (15)

ASSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) l On January 15,1994, at 1010 hours0.0117 days <br />0.281 hours <br />0.00167 weeks <br />3.84305e-4 months <br />. Unit I was in hiode 5 at 0% power. Increased reactor coolant pump  ;

j seal injection flow was identified following the start up of the Centrifugal Charging Pump 1 A for testing.

The pump was secured and subsequent investigation identified that the Centrifugal Charging Pump 1 A discharge bypass valve (CV-h10%8348) to the reactor coolant pump seal injection line hydro-pneumatically opened in violation of Technical Specification 3.1.2.3. The bypass valve opening was caused by a hydro-pneumatic transient that occurred when the Centrifugal Charging Pump 1 A was started. The valve was manually closed. Corrective actions include performing a review to identify other valves that may be susceptible to this type of event, adding a caution to the equipment clearance order database Ihr the affected valves and locally labeling all affected valves with a caution statement.

I 1

l NRC FORM 366 (5 92)

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- . - - . ,. , , . ~

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3 6 ) 0104 (5-92) . EXPIDES !i/U/95

. ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COL'.ECTION REQUEST: 50.0 HRS.

"'" ^ " " '"^

LICENSEE EVENT REPORT (LER) RECORD MANAGEMENT BRANCH MN TEXT CONTINUATION Nhi$".AND 7714), U.S NUCLEAR REGULATORY WASHINGTON, DC 20555 0001, AND TO THE PAPERWORK COMMISSION, REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND RUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION South Texas, Unit 1 05000 498 """ 8 " """ 8 " '

2OF4 94 - - 002 - - 01 TEXT (if more space is required, use additional copies of NRC form 366A) (17)

DESCRIPTION OF EVENT:

On January 15,1994, at 1010 hours0.0117 days <br />0.281 hours <br />0.00167 weeks <br />3.84305e-4 months <br />, Unit I was in Mode 5 at 0% power. Increased reactor coolant pump seal injection flow was identified fbilowing the start up of Centrifugal Charging Pump 1 A for testing. The pump was secured and subsequent investigation identified that the Centrifugal Charging Pump 1 A

! discharge bypass valve (CV-MOV-8348) to the reactor coolant pump seal injection line hydro-pneumatically opened in violation of Technical Specification 3.1.2.3.

i Maintenance had recently been completed on Centrifugal Charging Pump 1 A which required the pump to  ;

be isolated, uncoupled, and drained. After maintenance was completed, the system was statically filled. 1 Pump testing, which was required prior to the pump being returned to service, was scheduled to be  :

I conducted on January 15, 1994. Because the pump was inoperable, Technical Specification 3.1.2.3 )

required the pump discharge to be isolated from the reactor coolant system when the pump was run for j testing. This isolation was accomplished by Equipment Clearance Order which tagged the discharge

, bypass valve in the closed position and the valve motor controller breaker in the off position. Note, the discharge bypass valve, CV-MOV-8348, was stroke timed in November 1993 and had been properly verified to be in the closed position after testing. In addition, the valve had been verified closed on six other occasions during other maintenance activities on the charging system.

Prior to starting the test run of the pump, the Unit Supervisor conducted a pre-evolution brief with the I Reactor Operator and the Reactor Plant Operator assigned to the evolution. The Reactor Plant Operator was directed to physically check the pump ready to start and exit the pump room until the pump was running. After starting the Centrifugal Charging Pump 1 A, the following irregular indications were received on the control room control board:

The auxiliary lube oil pump indicating light did not extinguish as expected. Adequate lube oil pressure was verified, the auxiliary pump was secured and a work order was written to repair the pressure switch.

The seal injection filter high differential pressure alarm annunciated. The seal injection filters were shifted and the annunciator cleared.

Seal injection to all reactor coolant pumps increased to greater than 20 gallons per minute each. Seal injection flow was throttled in an attempt to return it to normal.

The seal injection flow could not be reduced by throttling so the Centrifugal Charging Pump 1 A was secured and it's associated breaker was racked out. The valve lineup for the Centrifugal Charging Pump was checked to determine if a valve was mispositioned. Discharge bypass valve (CV-MOV-8348) was determined to be open. The valve was manually closed.

L94087002.U1

i NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION ArPROVED BY OMB NO. 3150 0104 (5-92) . EXP!RES S/31/95

. ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS

, INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURDEN ESilMATE TO THE LICENSEE EVENT REPORT (LER) INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB TEXT CONTINUATION 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHIhGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF

< MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

i l FACIL11Y NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUMBER NUMBER i South Texas, Unit 1 05000 498 3OF4 94 - - 002 - - 01 TEXT (if more space is required. use additional copies of hRC f orm 366A) (17)

CAUSE OF EVENT The cause of the isolation valve opening was a hydro-pneumatic transient initiated when Centrifugal Charging Pump 1 A was started.

The valve was verified closed by indication at the start of the test. Valve position verification had

occurred six times since stroke time testing in November 1993. On January 4,1994, the valve was i

declutched and the handwheel engaged to verify the valve closed per the restoration section of the clearance order. Historical data taken from the Emergency Response Facilities Data Acquisition and Display System indicated the valve lifted slightly off its seat. This Emergency Response Facilities Data Acquisition and Display System (ERFDADS) indication coincided with the dynamic Motor-Operated Valve

Actuator Testing System (MOVATS) test of the seal injection valves on January 6,1994. Emergency a Response Facilities Data Acquisition and Display System continued to indicate the valve was open until the valve was manually closed on January 15,1994. The valve stroke is one to one and one-half inches and for the Emergency Response Facilities Data Acquisition and Display System to change state requires

, between I and 5 percent valve movement. The dynamic testing required charging pump 113 to be run and flow to the seal injection valves under test to be stopped and started numerous times. The hydraulic

transients generated by the pressure and flow being stopped and started were being applied to the down stream side of the centrifugal charging pump 1 A discharge bypass valve (CV-MOV-8348). The pressure and flow pulses caused the valve to rise offits seat.

l A system walkdown determined that static fill and vent of this portion of the charging system would not be  !

, sufficient to eliminate trapped air in the portion of piping between the pump and the bypass valve because the pipe run is vertical and there are no vent paths in this section of piping. Per discussion with the valve manufacturer, Limitorque, it is possible for the valve to hydro-pneumatically open due to the stem thread angle if the handwheel is engaged and if there is sufficient system pressure. Operations continued that the handwheel was engaged at the time of this event. The trapped air in the vertical section of piping coupled with the bypass valve being slightly offit's seat, and the handwheel engaged (effectively eliminating the actuator and motor gear ratios which would have maintained the valve closed against increased pressure on the valve dise) provided enough valve disc area to be available for the valve to be hydro-pneumatically stroked open upon starting the charging pump (pump output pressure approximately 2600 psi).

ANAI.YSIS OF EVENT This event is reportable pursuant to 10CFR50.73(a)(2)(i)(13). Technical Specification 4.1.2.3.2 requires that all charging pumps, excluding the one required operable pump, be demonstrated inoperable at least once per 31 days in Modes 4,5,6. This is accomplished by verifying that the motor circuit breakers are secured in the open position. The Technical Specification provides a note which states that an inoperable pump may be energized for testing provided the discharge of the pump has been isolated from the reactor coolant system by a closed isolation valve with power removed from the valve operator, or by a manual isolation valve secured in the closed position. Failure to maintain the valve in the closed position during testing constituted a condition contrary to the requirements of Technical Specification 3.1.2.3.

L94087002.U1

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150 0104 (5-92) . EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

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LICENSEE EVENT REPORT (LER) N$7[o$ME" AND REC RD MANAGEMENT BRANCH MN TEXT CONTINUATION 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUMBER South Texas, Unit 1 05000 498 NUMBER 4OF4 94 - - 002 - - 01 TEXT (If more space is required. use addit 10%I copies of NRC Form 366A) (17)

ANALYSIS OF EVENT - (Cont'd)

Since the valve failed to maintain its closed position, a condition contrary to Technical Specification 3.4.9.3 also occurred. Technical Specification 3.4.9.3 requires administrative control during testing periods )

on components which could result in a reactor coolant system mass or temperature increase. Per a review l of the control room log book, it was determined that when Centrifugal Charging Pump 1 A was started on i January 15,1994, at 1010 hours0.0117 days <br />0.281 hours <br />0.00167 weeks <br />3.84305e-4 months <br /> the seal injection flow increased which potentially resulted in an addition to the reactor coolant system mass. Technical Specification 3.4.9.3 was exited on January 15,1994, at 1055 hours0.0122 days <br />0.293 hours <br />0.00174 weeks <br />4.014275e-4 months <br /> when the power-operated relief valves were declared operable alleviating the requirement for administrative controls. As such, there was a time period between 1010 hours0.0117 days <br />0.281 hours <br />0.00167 weeks <br />3.84305e-4 months <br /> to 1055 hours0.0122 days <br />0.293 hours <br />0.00174 weeks <br />4.014275e-4 months <br /> when the administrative controls were required and not met.

Technical Specifications require an inoperable charging pump to be isolated from the reactor coolant system. This lequirement is based upon the mitigation of a mass input transient accident while in Modes 4,5, and 6 with the reactor vessel head installed. The mass input transient accident is described in the Updated Final Analysis Report Section 5.2.2.11.2 and the Safety Evaluation Report Section 5.2.2.2.

These documents assume that charging flow is injected into the reactor coolant system and letdown has been isolated. The conditions present during this event included letdown flow which would minimize the consequences of the mass input, therefore this mass input transient is determined to be not significant.

CORRECTIVE ACTIONS The following corrective action have or will be taken as a result of this event:

1. The MOV database was searched to identify other valves that may be susceptible to this type of event.
2. A note has been entered in the Unit 1 and Unit 2 Equipment Clearance Order database for all valves identified in corrective action 1 that cautions operators to electrically close the valves and not de-clutch the valve for manual < aration.
3. The affected Unit I r.a Unit 2 valves will be labeled locally with a caution statement. The Unit 1 valves have been labeled. This action will be completed for Unit 2 prior to Mode 6 entry.

ADDITIONAL INFORMATION-l There have been no previous similar events reported to the NRC.

L94087002.U1

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