ML18153C870

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LER 91-011-00:on 911217,automatic Reactor Trip Occurred as Result of Turbine Trip Due to High SG Level.Caused by Failure of B Main FW Regulating Valve to Maintain Demand Position.Valve Inspected,Replaced & tested.W/920114 Ltr
ML18153C870
Person / Time
Site: Surry Dominion icon.png
Issue date: 01/14/1992
From: Kansler M
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-035, 92-35, LER-91-011-03, LER-91-11-3, NUDOCS 9201210284
Download: ML18153C870 (5)
v • d • e


Text

ACCELERATED DiTRIBUTION DEMONSljATION SYSTEM.

  • REGULATORY INFORMATI_ON DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9201210284 DOC.DATE: 92/01/l4 NOTARIZED: NO DOCKET#

FACIL:50-281 Surry Power Station, Unit 2, Virginia Electric & Powe 05000281 AUTH.NAME AUTHOR AFFILIATION KANSLER,M.R. Virginia Power (Virginia 'Electric & Power Co.)

RECIP.NAME RECIPIENT AFFILIATION R

SUBJECT:

LER 91-011-00:on 911217,automatic reactor trip occurred as. I reisul t of turbine trip due to high SG level. Caused by fcLilure of "B" main FW regulating valve to maintain demand position.Valve inspected,replaced & tested.W/920114 ltr. D DISTRIBUTION CODE: IE2 2T COPIES RECEIVED: LTR l ENCL J . SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER),Incidenlt"-Rpt, et-c-.+-----

'!- s I

NOTES:lcy NMSS/IMSB/PM. 05000281 A

RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 D BUCKLEY,B 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 s AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFBlO .1 1 NRR/DLPQ/LPEBlO 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPBll 2- 2 NRR/DST/SELB SD 1 1 NRR/DST/SICB8H3 1 1 1 1 NRR/DST/SRXB SE 1 1 ~REG~L B 8 D02 FILE l 1 1 RES/DSIR/EIB 1 1 - FILE 01 1 1 EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR. 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1. 1 R NOTES: 1 1 I D

s I

A D

D NOTE TO ALL "RIDS" RECIPIENTS:

s PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, .

ROOM Pl-37 (EXT. 20079) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR

  • 34 ENCL 34

. Virginia Electric and Power Company Surry Power Station:

. January 14, 1992 U.S. Nuclear Regulatory Commission Serial No.: 92-035 Document Control Desk Docket No.: 50-281 Washington, D. C. 20555 License No.: DPR-37. *

.Gentlem:en:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power*

  • . Company hereby submits the following Licensee Event Report for Unit 2.

REPORT NUMBER 91-011-00

. This report has been revie~ed by the Station Nuclear Safety and Operat~ng Committee and will be reviewed by the Corporate Management Safety Review Committe~.

Enclosure cc: Regional Administrator Suite 2900

. 101 Marietta Stre~t, NW Atlanta, Georgia 30323 920121028~ 920114 PDR AbOCK 05000281

  • ' NRC FORM 355* . U.S. N_UCLEAR REGULATORY COMMISSION - APPROVED 0MB NO. 3150-0104

' . 16-89) * '

EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO co'MPLY WTH .THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP-530). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NA"1E_l1) DOCKET NUMBER 12) . I PAGE 13)

TITLE 141 Surry Power Station, Unit .2

}Jigh *steam 9enerator Level Due to Main F'eedwater Regulating Valve_

Io I 5 I o I o I o 12 I 81 ll 1 loF O 13 OscillatioQs Results irr ESF Actuation and Reactor Trip

  • EVENT DATE 15) LER NUMBER 16) REPORT DATE 171 OTHER FAC.ILITIES INVOLVED. IS)

MONTH DAY.- YEl,R YE-AR.

{ff SEQUENTIAL NUMBER \\( REVISION *MONTH NUMBER DAY YEAR* FACILITY NAMES DO_CKET NUMBERIS) 01s1010101 I I 112 117 9 1 9 I1 - o I 1 I1 - 010 Oil 1 14 9 12 0 I 5 Io Io I o I I I OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE R~OUIREMENTS OF 10 CFR §: (Chsck ons or mars of ths following) .(11)

MODE (9)

N I

20.402fbl 20.4061c) 60.7311H2Hiv) ..__ 73.711b) t--"----,.---...J.-,-+---1 ...._ I~

POWER 20.406(a)l1)11) ..__ 50.36Jc)l1) 60.73loll21M 73.71 lc)

LEVEL ...._ ...._ ..__

0 I 21 3 . . 20.40511H1 Hill 50,38lcll2) 60.7311)121(viil

._ OTHER (Spt1cify in Abstracr 1101 *

....- below *nd in Text, NRC Form 20.405(0)11 )lili)

- 50.7311H2lli) 60.7311)(2)1viiillA) 366A)*

20.40611)11 Hlvl 20.40511)11 )Iv)

- 50.73(1)12iliil 60.73(1)12)(iiil

._ 60.73(~1(2)(vlli)(B) 60.73(1112ll*I LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 1131 MANUFAC- MANUFAC*

CAUSE SYSTEM COMPONENT TURER TURER X C I 61315 y I . I I I I I I I I I I. I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED

~

SUBMISSION DATE 115)

~ YES (If yss, compltir* EXPECTED SUBMISSION DATE) NO I I I ABSTRACT (Limit to 14170 spaces, i.e., approximately fiftetm single-space typewritten lines} (161

  • on December 17, _1991, at 2254 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.57647e-4 months <br />, with Units 1 and 2 at 100% and 23%

power, respectively, a* Unit 2 automatic reactor trip occurred as a result of a turbine trip due to high steam generator (SG) level. The required safety systems performed as designed, appropriate operator actions were taken to ensure the performance of system automatic actions, and the unit was quickly brought to a stable no-load condition. The cause of this event is attributed to the failure of the "B" main feedwater regulating valve (MFRV) to maintain a demand position. This condition resulted in a high SG level, the main feedwater pumps tripping, automatic start of auxiliary feedwater (AFW} pumps, turbine trip, and an automatic reactor trip. The "B" MFRV was inspected on December 18, 1991.

The positioner was found to be worn and was replaced and* tested. During the subsequent unit startup on December 18, 1991, a similar less severe *oscillation of the subject valve was noted. Therefore, a Root Cause Evalua,ion is being performed to determine the cause of this condition. A non-emergency four-hour report,. pursuant. to 10CFR 50.72(b)(2)(ii), Was made to the Nuclear Regulatory Commission at 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br /> on December 18, 1991. This event is

  • being reported, pursuant to 1o CFR 50.73(a)(2)(iv), as an unplanned Engineered Safety_ Feature actuation as a result of a valid signal.

NRC Form 366 (6-89)

NRC FORM 366A (6-89) .

e LICENSEE EVENT REPORT (LERI U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXP.IRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1'HE PAPERWORK REDUCTION PROJECT (3150-01041, OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

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

Surry Power Station, Unit. 2 o 1s10101012 1s*11 911 -01111 - 010 .o'12 oF o 13

.TEXT./ff more space is requireo, use additional NRC Form 366A's/ (17)

1. 0 DESCRIPTION OF JHE EVENT On December 17, 1991, at 2254 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.57647e-4 months <br />, with Units 1 and 2* at 100% and 23%

power, respectively,. a Unit 2 automatic reactor trip {EIIS-JC} occurred as a result of a turpine trip {EIIS-JI} due to high steam generator (SG) {EIIS-SB,SG}

level. *

  • This event occurred during a 1.50 MWe/hr turbine ramp up of Unit 2 following a startup from Cold Shutdown. At 2251 hours0.0261 days <br />0.625 hours <br />0.00372 weeks <br />8.565055e-4 months <br />, feedwater. {ELIS-SJ} and steam flow were matched for tt)e "B" SG and the respective main feedwater regulating valve *

(MFRV) {EIIS-SJ,FCV} was placed in the automatic control inode.. At approximately 2252 hours0.0261 days <br />0.626 hours <br />0.00372 weeks <br />8.56886e-4 months <br />, a reactor operator observed* the "B" MFRV opening and closing at a rapid rate. This condition lasted approximately* 50 seconds. It was noted from Emergency Response Facility Computer System (ERFCS) {EIIS-NC,CPU} data that during this period of time

  • feedwater header pressure underwent significant perturbations. At 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br />, the "B" MFRV *was retumed to the manual control mode and the MFRV demand was reduced to zero in an effort to stop the oscillations. During this period, feedwater flow indications were erratic and "B" SG level rose rapidly. In approximately ten seconds SG level increased to 74% and the unit senior reactor operator directed the unit be manually tripped. Immediately following this direction, the main feedwater pumps {EIIS-SJ,P} and turbine tripped, resulting in the automatic start of the "A" and "B" motor driven auxiliary feedwater (AFW) pumps {EIIS-JE,BA,P} and an automatic reactor trip, respectively. The reactor was manually tripped less than three seconds later. .

{EIIS-AA,ROD} were verified properly. inserted .. At 2256 hours0.0261 days <br />0.627 hours <br />0.00373 weeks <br />8.58408e-4 months <br />, Reactor Coolant system (RCS) letdown {ElfS-AB} was isolated due to low pressurizer {EIIS-AB,PZR} level associated with the cooldown. Pressurizer heater breakers {EIIS-AB,BKR} opened as designed. At 2312 hours0.0268 days <br />0.642 hours <br />0.00382 weeks <br />8.79716e-4 months <br />, the "A" motor driven auxiliary feedwater pump was stopped and placed in pull-to-lock. .At 2325 hours0.0269 days <br />0.646 hours <br />0.00384 weeks <br />8.846625e-4 months <br />, the .

normal. procedure for unit shutdown was initiated.

A non-emergency four-hour report, pursuant to 10CFR 50.72(b)(2)(ii), was made to 'the Nuclear Regulatory Commission at 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br /> on December 18, 1991. This event is being reported, pursuant to 10 CFR 50.73(a)(2)(iv), as an unplanned Engineered Safety Feature (ESF) actuation as a result of a valid signal.

2. C> SAFETY CONSEQUENCES AND IMPLICATIONS During* this event, the required safety systems
  • performed as designed, appropriate operator actions were taken to ensure the performance -of system automatic actions, and the unit was quickly brought to a stable no-load condition.

Therefore, the health and safety of the public were not affected.

NR~ FORM-366A

'(6-89) .

e LICENSEE EVENT REPORT (LERI TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION

  • APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 DOCKET NUMBER (2) LER NUMBER (6) PAGE (31 YEAR {:( SE~~~~~lif L :()J~~t~S~~~

Surr*y Powe_r Station, Unit 2 TEXT /If mo,. space is f9quireo; usa*additional NRC Form 366A's/ 117) 0 1s IO IO ro I 21 s 1 1 911 - 0 11 11 -1010 Ol 3 OF O I3 3 .o CAUSE The cause of this event is attributed to the failure of the "B" MFRV to maintain a demand position. This condition resulted in a high SG level, the main feedwater pumps tripping, automatic start of AFW pumps, turbine trip, and an automatic reactor trip.

  • 4 .O IMMEDIATE CORRECTIVE ACTION(Sl Following the reactor trip, control .-room operators promptly initiated the appropriate emergency procedures to verify the reactor trip breakers were open and that all control rods were properly inserted. The Shift Technical Advisor monitored the critical safety function status trees to ensure that plant parameters remained within* safe bounds.

5 .O ADDl!IONAL CORRECTIVE ACTjONCS)

On December 18, 1991, Engineering performed an inspection of the feedwater piping (outside containment) to assess the effects of the transient associated with the "B" MFRV oscillations. No significant displacements of feedwater piping or damag~d supports {EIIS-SJ,PSP,SPT} were identified during this inspection.

6. O ACTIONS TO PREVENT RECURRENCE The "B" MFRV was inspected on December 18, 1991. The positioner {EIIS-SJ,FCV,FCO} was found to be worn and was replaced and tested. During the subsequent unit startup on December 18, 1991, a similar less severe oscillation of the subject valve was noted. Therefore, a Root Cause Evaluation (RCE) is being performed to determine the cause of this. condition. Based on the RCE, further corrective actions will be implemented, as appropriate.
7. o SIMILAR EVENTS LER 85-002-00 Reactor Trip (Low Steam Generator Level)

LER 85-013-00 Turbine Trip/Rx Trip - Hi S. G. Level LER 89-010-00 Reactor Trip Due to Low Steam Generator Level Following a Higher Than Expected Load Increase During Unit Startup

8. o MANUFACTURER/MODEL NUMBER Manufacturer: Copes - Vulcan Inc.

Model Number: A6795-ECDl-92341 SEMI NRC Form 366A 16-89)

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