ML20045E230

LER 93-013-00:on 930530,RCIC Sys Declared Inoperable & 7 Day TS 3.5.D.2 LCO Entered Due to Speed Oscillations Which Occurred After Several Minutes of steady-state Operation. Caused by Actuator Failure.Actuator replaced.W/930625 Ltr

ML20045E230
Person / Time
Site:	Pilgrim
Issue date:	06/25/1993
From:	Boulette E, Gay R BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BECO-LTR-93-81, LER-93-013, LER-93-13, NUDOCS 9307010271
Download: ML20045E230 (5)

Text

m: -

c., .. .

gi 10 CFR 50.73 BOSTON EDISON

, ' Pilgrim' Nuclear Power Staton Rocky Hill Road Ptymouth, Massachusetts 02360 E. T. Boulette, PhD

' Sinior Vee President-Nuclear June 25 , 1993 BECo Ltr. 93- 81 V' S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Docket No. 50-293 License No. DPR-35 The enclosed Licensee Event Report (LER) 93-013-00, " Reactor Core Isolation Cooling System Declared. Inoperable Due to Turbine Speed Oscillations During Surveillance Testing", is-submitted in accordance with 10 CFR Part 50.73.

Please do not hesitate to contact me if th are any questions regarding this- '

report.

T Sdt E. T. Boulette, PhD .

RAG /bal

Enclosure:

LER 93-013-00 cci Mr. Thomas T, Martin Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Rd.

King of Prussia, PA 19406-  ;

Mr.-R. B. Eaton Div. of Reactor Projects I/II Office of NRR.- USNRC

~

One White Flint North - Mail Stop 14D1 11555 Rockville Pike Rockville, MD 20852 Sr. NRC Resident Inspectcr - Pilgrim Station Standard BEco LER Distribution 010033 f6p(

pesumgr

MRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 n-u) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS

. LICENSEE EVENT REPORT (LER) 1""S' " reg 0$'@ UnMEMOLFi!M AND RECORDS MANAGEMENT BRANCH (MNBB 7714). U.S. NUCLEAR TO APE F1 CT 1 0-0104 FICE (see rowerse for rumber of digita/charatter, for each blocid OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

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

PILGRIM NUCLEAR POWER STATION 05000 -293 1 of 4 TITLE (4)

Reactor Core isolation Cooling System Declared inoperable Due to Turbine Speed Oscillations During Surveillance Testing EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

SEQUENTIAL REVISION FACfUTY NAME DUCKET NUMBErg MONTH DAY YEAR YEAR NUMBER NUMBER MONTH DAY YEAR N/A 05000 FACILfTY NAME DOCKET NUMBET1 05 30 93 93 013 00 06 25 93 N/A 05000 OPERATING THIS REPORT IS SUBMITTED PURSUAf fT TO THE REQUIREMENTS OF 10 CFR 6: (Check one or rriore)(11)

- ODE (9) N 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

L E 10) 019 aM McW X WNam a mm 20.405(a)(1)0i) 50.36(c)(2) 50.73(a)(2)(vii) OTHER 20 405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) 20.405(a)(1)6v) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) ,

20.405(a)(1)(v) 50.73(a)(2)Dii) 5173(a)(2)(x) Form assA; -

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (Include Area Code)

Robert A. Gay - Senior Cornpliance Engineer (508) 747-8047 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTUHER PRDS CAUSE SYSTEM COMPONENT MANUFACTURER S X BN 65 W290 Y SUPPLEMENTAL REPORT EXPECTED (14) " '

• U^# "E*"

EXPECTED YES X NO SUBMISSION tw yea, compieie EXPECTED SUBMISSION DATE)

DATE (15)

ABSTRACT (16)

On May 30,1993, at 1820 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.9251e-4 months <br />, the Reactor Core Isolation Cooling (RCIC) System was declared inoperable and a seven day Technical Specification (3.5.D.2) Limiting Condition i for Operation (LCO) was entered. The RCIC System was declared inoperable during a '

scheduled surveillance test. The RCIC System was returned to normal standby service during subsequent investigative and corrective action activities.

The RCIC turbine was declared in0perable due to speed oscillations that occurred after several minutes of steady operation. The cause of the oscillations is believed to be a mechanical failure of the speed control system hydraulic actuator (EG-R). The actuator was manufactured by Woodward Governor Company, part number A9903-026. The actuator was removed from service and a replacement EG-R was installed and calibrated. The RCIC System was inoperable when an unplanned reactor scram occurred on May 31, 1993, at 1921 hours0.0222 days <br />0.534 hours <br />0.00318 weeks <br />7.309405e-4 months <br />.

The RCIC System was tested with satisfactory results, after restart from the scram, and declared operable on June 4, 1993, at 0618 hours0.00715 days <br />0.172 hours <br />0.00102 weeks <br />2.35149e-4 months <br />. While the RCIC System was inoperable, the High Pressure Coolant Injection System was verified to be operable as required by Technical Specifications.

The event occurred during power ascension. The reactor mode selector switch was in the RUN position. The reactor power level was approximately 19 percent. The Reactor Vessel (RV) pressure was 939 psig and the RV temperature was approximately 538 degrees Fahrenheit. This report is submitted in accordance with 10 CFR 50.73(a)(2)(v)(D). This event posed no threat to the public health and safety.

NRC FORM 3664 @S2l

_.e FORM 366A U.S. NUCLEAR REGULATORY COMM!SSION

' APPROg8YO 8 0 3150-0104 ESTEAATED BURDEN PER RESPONSE TO COMPLY'wrIH THIS f

. LICENSEE EVENT REPORT (LER) . "OM"nEa%""#Eno"Eu"'1LU00 !=

c 1 TEXT CONTINUATION E[Todc"xEEwYust'" E*Es'aE,*$

$ u" aid Nr E s N As Ysm,"o'cD

- FACIUTY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) f vEAn 'w'uf5En* E 2W PILGRIM NUCLEAR POWER STATION 05000-293 93 --013- 00 f 1 EXT (if more space is required, use additional ccpies of NRC Form 366A)(17)  ;[

EVENT DESCRIPTION On May 30,1993, at 1820 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.9251e-4 months <br />, the Reactor Core Isolation Cooling (RCIC) System was  ;

declared inoperable and a seven day Technical Specification (3.5.D.2)'Li_miting Condition: s; for Operation (LC0) was entered. .The RCIC System was being surveillance tested in-accordance with Procedure 8.5.5.1;(Rev. 35),. "RCIC Pump Operability Flow Rate and Valve Test at Approximately 1000 psig". The system was declared inoperable when turbine speed.

oscillations were observed and the turbine was manually tripped. Following initial -

investigation, Maintenance Request 19302307 was issued. I Prior to the event, the'RCIC turbine operated for approximately thirteen minutes with no identified oscillation problems. In' addition, surveillance. Procedures 8.5.5.3 (Rev. 21), .

"RCIC Flow Rate Test at 150 psig" and 8.5.5.8 (Rev. 6), "RCIC 0verspeed Trip Test" had

.been satisfactorily performed on May 29, 1993.

After the RCIC System.was declared inoperable, operability of the High Pressure Coolant-Injection (HPCI) System was verified as required by Technical Specifications.

~

Problem Report 93.9282 was written to document the event. The NRC Operations Center was l notified in accordance with~10 CFR 50.72 on May 30, 1993,-at 1844 hours0.0213 days <br />0.512 hours <br />0.00305 weeks <br />7.01642e-4 months <br />. r

.The event occurred during power ascension. The reactor mode selector switch wasLin the-

.RUN position. The Reactor Vessel (RV) pressure was 939 psig with.the.RV water temperature at approximately 538 degrees Fahrenheit. ,

CAUSE l The direct cause of the turbine speed oscillations was th'e ' failure of the speed control system hydraulic actuator (EG-R). During performance of surveillanco Procedure 8.5.5.1, with the turbine speed controller in the automatic position, speed. oscillations ~were '

observed. The oscillations occurred after approximately thirteen minutes of steady' operation at rated pump flow conditions. .The turbine. speed oscillations prompted i operators to manually trip the RCIC turbine and declare the system inoperable. i

'l Troubleshooting of the turbine speed control system was performed in'accordance with Procedure 3.M.1-34 (Rev. 7),'" Generic Troubleshooting and.Maintena'nce' Procedure". Results = 1

~

-confirmed the flow controller, signal converter and the speed control electric governor

. (EG-M) were functioning properly. The troubleshooting also indicated the speed 9 oscillations were likely caused by a mechanical failure of the speed control system-hydraulic actuator,(EG-R).

Based on examination of the failed EG-R by Systems Engineering personnel when this report.

was prepared, the root cause of the EG-R failure was most likely due to the amount and

. size of ' grit' discovered inside the failed'EG-R, which caused mechanical: binding-and wear of the pilot plunger assembly. An investigation to identify the source of the-grit is being conducted. -The EG-R was manufactured by the Woodward Governor Company-(part number -

- A9903-026) _.

~ mono, Ag

a. ~- ,,;,- /. -

NRC FORM 366A U.S. NUCLEAR REGULATORY Commission APPROVE B O B O 3150-0104 ESTIMATED BUHDEN PER RESPONSE To COMPLY WITH THrs LICENSEE EVENT REPORT (LER) 1%l"%'"EMATuk"#F#JfoLO1%

n TEXT CONTINUATION E7 Tom Es's"irIn*TA$w"oTTEAEN

$uY EE Nos"'u S AsTHaTos E E i FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) vtan *[uEa" EuSE"n PILGRIM NUCLEAR POWER STATION 05000-293 93 --013- 00

^ ~

TEXT (tf more space is required, use additional copies of NRC Form 366A)(17)

The failed EG-R was the same unit (Serial No. 2277086) that failed on August 15, 1991 (LER 91-020-00). The cause of the failure at that time was determined to be excessive wear of the pilot plunger assembly. The EG-R was refurbished by Woodward Governor Company and returned to . stock.

CORRECTIVE ACTION The speed control system hydraulic actuator (EG-R) was replaced.

Prior to the event, the oil supplied to the EG-R was flushed and refilled in accordance with Procedure 3.M.4-17.4 (Rev. 12), " Lubrication Sampling and Change Procedure". The oil filter was inspected and determined to be clean.

The turbine speed control system, including the new EG-R, was adjusted and calibrated in accordance with Procedure 8.E.13.1 (Rev. 3), "RCIC Turbine Speed Control System Calibration" with satisfactory results. The RCIC System was then retested satisfactorily in accordance with Procedure 8.5.5.1 (Rev. 35) and declared operable on June 4,1993, at 0618 hours0.00715 days <br />0.172 hours <br />0.00102 weeks <br />2.35149e-4 months <br />.

An analysis of the RCIC oil filter will be performed to verify its ability to consistently capture the type of grit material found inside the failed EG-R.

Samples of the EG-R oil were taken and sent offsite to be tested for impurities.

This report will be updated if significant new corrective action are necessary as a result of Systems Engineering findings that had not been finalized when this report was prepared.

SAFETY CONSE0VENCES This event posed no threat to the public health and safety.

During the period the RCIC System was inoperable, operability of HPCI was verified as required by Technical Specifications. The Automatic Depressurization System was also available to reduce Reactor Vessel pressure for low pressure cooling that is'provided independently by the Core Spray System and the Low Pressure Coolant injection mode of the Residual Heat Removal System.

This report is s emitted in accordance with 10 CFR 50.73(a)(2)(v)(D) because the RCIC System was declared inoperable.

SIMILARITY TO PREVIOUS EVENTS A review was conducted of Pilgrim Station Licensee Event Reports (LERs) submitted since January 1984. The review focused on LERs submitted in accordance with 10 CFR 50.73(a)(2)(v) that involved RCIC/HPCI turbine trips due to problems with the turbine speed control hydraulic actuator (EG-R). The review identified related events reported in LERs 50-293/90-013-00, 90-017-00 and 91-020-00.

wnc mnu ma m

N FORM 366A . U.S. NUCLEAR REGULATORY COMMISSION APPROVE BO8 3150-0104 ESTIMATED BURDEN PEH RESPONSE TO COMPLY WITH THIS

. LICENSEE EVENT REPORT (LER) L'0"#"ca"E"O#3ET7k"TLA"*O s ,

I TEXT CONTINUATlON

• n E 7anv* E u' s's"$ T s E tont *""*S$s*ooNo

'c0u'"INNcEosE$As7NG 4 ON?C j FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) vEAn EEltn" EaYn .

. 4 g,4-PILGRIM NUCLEAR POWER STATION 05000-293 93 -013- 00 TEXT (It more space is required, use additional copies of NRC Form 366A)(17) '

For LER 90-013-00, overspeed trips of both the RCIC and HPCI System turbines occurred. .i The RCIC turbine trips were attributed to an-improper manual start sequence specified in;

• the operating procedure and/or looseness of the mechanical overspeed trip linkage. The procedure was revised and adjustments were made to the overspeed trip linkage. Regarding 1 the HPCI overspeed trips, it was determined that the EG-R needle valve needed adjustment." ,

.In addition, the RCIC/HPCI turbine oil contained impurities and a significant amount of-water. The system was flushed and the oil was changed. j for LER 90-017-00,- the HPCI turbine tripped on overspeed during a scheduled surveillance _

test. The cause was determined to be a stiff pilot relay valve spring and misalignment-o.f the pilot relay valve oil porting holes. The pilot relay valve is part of the turbine's- -

governor control system. The concerns identified with this valve resulted in an inherent. '

slow response of the control valves to the electronic control signal, and subsequent  ;

overspeed trips. Corrective actions taken included replacement of-the EG-R and pilot  ;

relay valve spring. The pilot relay valve oil ports were also realigned.

For LER 91-020-00, the RCIC turbine was manually tripped due to speed oscillations that l occurred after approximately twelve minutes of steady operation. The cause of the i oscillations is believed to be a mechanical failure of the speed control system hydraulic -i actuator (EG-R). Corrective actions taken included replacement of the (EG-R) and the  ;

removed actuator was sent to the manufacturer for testing and examination. 'The EG-R was i refurbished by the manufacturer and returned to stock. The oil supplied to the EG-R.was r tested, flushed and refilled. Analysis of the oil sample indicates the oil was in satisfactory condition.  :

't MERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) CODES

.i The EIIS codes for this report are as follows: '

COMPONENTS CODES Control, Speed SC Governor 65 SYSTEMS .

Reactor Core Isolation Cooling (RCIC) System BN i

?

tm FonM 3064 @M

, - - , -- -. , , , . , _