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Icnnoss e VMey AunWy PoM Oke hav NXX)Addy-Da sy Teniesee 37370

February 15, 1991

U.S. Nuclear Regulatory CommiesionATTN Document Control DeskWashington, D.C. 20555

Gentlement

In the Matter of ) Docket Nos. 50-327Tennessee Valley Authority ) 50-328

SEQUOYAH NUCLEAR PLANT (SQN) - JANUARY 199'. MONTHLY OPERATING REPORT

Enclosed is the Janaury 1991 Monthly Operating Report as required by SQNTechnical Specification 6.9.1.10.

If you have any questions concerning this matter, please call M. A. Cooper at(615) 843-8422.

Very truly yours.

TENNESSEE VALLEY AUTHORITY

,

E. G. Wallace, ManagerNuclear Licer. sing and

Regulatory Ai'atrs

Enclosureec: See page 2.

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9102260176 9.10131jDR ADOCK 05000327 ')dy

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U.S. Nuclear Regulatory Commission

February 15, 1991

cc (Enclosure):Mr. J. N. Donohew, Project ManagerU.S. Nuclear Regulatory CommissionOne White Flint, North11555 Rockville PikeRockville, Maryland 20852

INPO Records CenterInstitute of Nucicar Power Operations1100 Circle 75 Parkway, Suite 1500Atlanta, Georgia 30389

Mr. Ted Marston, DirectorElectric Power Research InstituteP.O. Sox 10412Palo Alto, California 94304

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NRC Resident Inspector,

Sequoyah Nuclear Plant2600 Igou Ferry RoadSoddy-Daisy Tennessee 37379

Regional AdministrationjU.S. Nuclear Regulatory Commission

Office of Inspection and EnforcementRegion II101 Marietta Street, NK, Suite 2900Atlanta, Georgia 30323

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Mr. B. A. Wilson, Project ChiefU.S. Nuclear Regulatory CommissionRegion II101 Marietta Street, NW, Suite 2900Atlanta, Georgia 30323 .j

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TEhWESSEE VALLEY AUTHORITY

NUCLEAR POWER GROUP

SEQUOYAH NUCLEAR PIANT

MONTHLY OPERATING REPORT

TO THE

NUCLEAR REGULATORY COMMISSION

JANUARY 1991,

UNIT 1

DOCKET NUMBER 50-327

LICENSE NUMBER DPR-77

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UNIT 2

DOCKET NUMBER 50-328>

LICENSE NUMBER DPR-79

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OPERAIl0NAL SE!ARY-

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JNARY1991

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UNIT 1

Unit 1 generated 871,480 megawatt hours (MW ) (gross) electrical power ;hduring January, with a capacity factor of 100.8 percent. Unit 1 operated at !

approximately 100 percent reactor power level the entire month.

UNIT 2 |1

Unit 2 generated 791,150 MWh (gtoss) electrical power during January, with acapacity factor of 91.51 percent.

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on January 3, lo91, at 1321 Eastern standard time (EST), Unit 2 operatorsbegan a load reduction after they discovered problems with the No. 3 heaterdrain tank (ilDT) level control valves (LCVs). During the manual runback, an !

automatic runback occurred when the No. 3 HPT bypass valves opened to divertflow to the main condenser. This automatic runback occurred without incident,and the unit stabilized at approximately 72 percent reactor power.

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In order to conduct repairs to the No. 3 !!DT LCVs, it was necessary to reducereactor power to approximately 60 percent. Reducing power required gettingthe turbine electrohydraulic control (EllC) system back to normal and of f of ,

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the governor valve limiter, which had performed the automatic runback. Duringthis reset process, the governor valves began closing and would not stop.Investigation determined that the turbine EllC system was receiving anartificially high input for turbine impulse pressure caused by a dampeningvalve that had vibrated closed. Closure of the governor valves resulted in aturbine / generator trip on generator reverse pow :. A subsequent steamgenerator (S/G) high-high level resulted in an etigineered safety feature (ESF)actuation (feedwater isolation (FWI] and auxiliary feedwater [AFW) pumpsstartit.g). The reactor entered Mode 2.

Following investigation and corrective actions. Unit 2 was again tied onlineat 0415 EST on January 5,1991. Unit 2 reached 100 percent reactor powerlevel at 2308 EST on January 7, 1991 and operated at near 100 percent throughthe end of January.

P0E0PERATED RELIEF VALVES (PORVs) AND SAFETY VALVES SMARYii

There were no challenges to PORVs or safety valves in January.

0FFSITE DOSE CALOUIATION MANE (0DCM) CEEES<

There were no changes to the ODCM during January. -

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AVERACE DAILY UNIT POWER LEVEL j*

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DOCKET NO. 50-327 UNIT No. , One DATE: _02-07-91

COMPLETED BY: T. J. Hollomon TELEPHONE: (615) 843-7528

MONTil: JANUARY 1991,

1

AVERAGE DAILY POWER trVEL AVERAGE DAILY. POWER LEVEL

DAY (MWe-Net) DAY (MWe-Net), . .

1 1133 17 1133

2 1131 18 11.34 _,

3 1129 19 1135. , _ _

4 .1130 20 1139

5 1131 21 1139_,

6 1132 22 1139_

7 1132 23 1137

8 1131 24 1138

9 1133 2$ 1132_

10 1132 26 1138

11 1133 27 1136

12 1132 28 1134-

13 1133_ 29- 1135

14 1133 30 1136

15 1133 31 1135

16- 1132 >

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AVERAGE DAI*,Y UNIT POWER LEVEL'

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DOCKET NO. 50-329 UNIT No. Two DATE: __02-07-91

COMPLETED BY: T. J. Ho11omon TELEPHONE: (615) 843-7528 |

MONTH: JANUARY 1991

AVERAGE DAILY POWER LEVEL AVERAGE DAILY POWER LEVELDAY (MWe-Net) DAY (MWe-Not)_

1 1126 17 1132

2 1127 18 1133

3 677 19 1132~

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4 -33 20 1133_.

5 135 21 1133_

6 657 22 1133

i7 954 23 1133-|

8 1131 24 1132i

9 1132 25 1132'

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10 1132 26 1132

11._ 1135 27 1132-,

12 1134 28 1133_ _ _ _

13 1134 29 1132,

14 1134 30 1133

15__ 1134' 31 -- 1131-

16 '1135

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-OPERATING DATA REPORT

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* DOCKET NO. 50-327. .DATE _ reb. 7. 1991

COMPLETED BY f.1. Ho11 mi0

TELEPHONE f615) 843-7E2a__

OPERATING STATU$

-| Notes ||1. Unit Namet'_ $th2Xah tinit One |. H .2. Reporting Period .1anuary 1991

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3. Licensed Thermal Power (HWt): 3411.0 |4, Nameplate Rating (Gross HWe):. 1220.65. Design Electrical Rating (Net HWe) _1148_06. Maximum Dependable Capacity (Gross HWe): _1162.0 |7. Maximum Dependable Capacity (Net HWe):' 1122.0' JL' -l8. If Chan9es Occur in Capaci*y Ratings (Items Number 3 Through 7) $1nce tast' Report. Give ReasonstJesuovah Nue1 gr P1. ant salance of Plant tvitant anointern have attabl { thed, a more accurate _ arestA

ngglinum deoendable caneeliv f GMDC) and not maximum dgpandable canacity (HHDC) based on NRC_ definitions.

9. Power Level To Which Restricted. If Any (Net HWe)! N/A,

10. Reasons For Restrictions. If Anyt N/A '.)'

This Month' Yr-to-Date- Cumulative

11. Hours in Reporting Period 744 144' 84.049,,,,,_

12. Number of Hours Reacter Was Critical 74(.0- 744.0 40.816,

13. Reactor Reserve Shutdown Hoers'- ~0 0 'O14. Hours Generator On-Line 744 0 744.0 39.840.0.

15. Unit Reserve Shutdown Hours. 0. 0 - 0 .,,_ 0 i16. Gross Thermal Energy Generated (HWH) i2.536.489.4 2.536.489.4 i 129.822.556

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17. Gross. Electrical Energy Generated (HWH) ,,_B71.480 871.480 '43.992.06618, Net Electrical Energy Generated (HWH) 840.681- 840.681 42.137.557_a19. Unit Serviro Factor -100.0 100.0 g 47.420. Unit Availability Factor 100.0- 100.0 47.421. Unit Capacity Factor (Using HDC Net); 100.7 '100.7 ' '44.722. Unit Capacity Factor (Using DER Net) 100.7 100.7 44.723. Unit Forced Outage Rate M, 0.0

' _44.8

24. Shutdowns Scheduled Over Next 6 Honths (Type. Date ind Duration of Esch) |

i25 -IF-$ hut Down' At End Of Report Period. Estimated Date.o': Startup '',,,,ti/1,,

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'OPERATING DA7A REPORT

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i*DOCKET NO. 50-328 _.

.DATE Feb. 7. 1991 '.

COMPttTED BY T. 3. Hollomon |, TELEPHONE f6151 B43-752L,_

OPERAtlNG STATUS

| Notes Li1. Unit Name: tenuovth Unit two | ,

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2. Reportlng Period: _ January 1991 ,-| j3. Licensed Thermal Power (HWt): J411.0 | |

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4. Nameplete Rating (Gross HWe); ,,121(L6 _ | |'

5. Design Electrical Rating (Net HWe): 1148.0 | |6. Maximum Dependable Capacity (Gross HWe): 1162.0 |L Maximum Dependable Capacity (Net HWe)!. 1122.0 l;

8. If Changes Occur in Capacity Ratings (!tems Number 3 Through 7) $1nce Last Report..Give Reasons!- -)_ seauovah Nuclear Plant Balance _ of. Plant tytingngingars harg_.411ablished a. more accurate _ GMDC and NMDC baigg[._on NRC definitight.-

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9. Power Level To Which Restricted. If Any (Net HWe); N/A '

10. Reasons for Restrictions, if Any! N/A1

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ThIs Month Yr-to-Date Cumulative-

11. Hours in Reportleg Period 744 7'44 76.00912. Number of Hours Reactor Was Critical 744.0 '744.0 41.21513. Reactor Reserve Shutdown Hours O' 0- 0.

14. Hours Generator On-Line 707.0 707.0- 40.267.415. Unit Reserve Shutdown Hourt _ - . 0.0 0- ~ 0 '

16. Gross Thermal Energy Generated (HWH) _2.316.660.3 '2.316.660.3 124.591.11117. Gross Electrical Energy Generated ('WH) 791.1!io 791.150 =42.279.36618. Net Electrical Energy Generated (HWi) 762.175 762.175 ' __40.388.253 i

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19. Unit Service factor 95.0 95.0 s LO.,,,,,20. Unit Availability Factor ._ 95.0 9s.0 53.021. Unit Capacity factor (Using HDC Net) 91.3 91.3. 47.422. Unit Capacity factor (Using DER Net) 91.3 91.3 47.4 l23. Unit Forced Outage Rate- 5.0 B.0_ 40.0_.

24. Shutdowns Scheduled Over Next 6 Hsnths (7 pe .' ate, and-Duration of Each): .f r

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25. If Shut Down At End Of Report Period, Estimated Date of Startup:; N/A' k,

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DOCKET NO: 50-327 - ',. UNIT SHOTDOWN5 AND POWER REDUCTIOt:5 UNIT NAME: _ _Jnt __._'

| DA T E:__.2D _7ISL__ ,,

! REPORT NONTH: Januarv 1991 COMPtETED BY:L_ L_tinihmon .|- TELEPt10NE:I615) 843-7528 .*

Method of Licensee Cause and Corr * tiveDuration 5 hatting,Down Event Systy Cyt Action to

l 2 Code Prevent RecurrencaNo. .Date Type (Hours) Reason Reactor Report No. Code3

|No activities during January 1991.

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I: Forced 2 R2ason: h thod: kshibitGInstructionsF5: Scheduled : A-Equipment Failure (Explain) 'l-Maneal ' for Freparation of Data

B-Maintenance or Test 2-Manual Scram ' Entry sheets for LicenseeC-Refueling 3-Automatic Scram Ennt Report (LER} FileD-Regulatory Restruction 4-Continuation of Existing Octatpe (MUREG-1022}E-Operator Training and Eicense Examination 5. Reduction:F-Administrative'' .9-Other

SEnhibit I-Same SevrteG-Operational Error (Explain)H-Other (Explain)

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DCSEI C1: M-A'3UNIT SPQJIIQiP45 AND PUwldt REDIKilONS (MIT NAMF:_ __ I w9 __ *

OAff:_QUQUJL_ .

REPORT month:jnary 1991 EOMrtETfD BV:TmJ,_lM h%n,IE t t PHOM :(fg !51 P U-%3 ,

| Method of Licensee ~ Cause and Corre(tiveA(tion toDuration Shutting Down Event Systp E g ent

No. Date Type (Hours ) Reason 2 Reacto.3 Report No. Code Eode Frevent ReterrenteI

1 950103 F 36.97 A 5 50-326/91001 IT LC On Janu ry 3.1931, at 132: (EST).Unit 2 operators began a loadreduction af ter they discoveredproblems with the No. 3 HDI LCVs.During manual runback, an autorunback otturred i. hen the No. 3 miip

r1 bypass valves epened to dieert flow,

' to the main condenser. This auto~;runback occurred without incident.

E and the wait stabilized at72 percent reacter power. In

'~ order to conduct repairs to theNo. 3 HDT LCVs. it was necessary toreduce reactor power to 60 pertent.Reducing power required gettingthe turbine EHC back to noririal andoff of the governor valve (GV)limiter,i.hich had performed theauto runback. During this resetprocess, the GYs began closing andenould not stop, i.hicS resulted ina turbine and generator trip on

2gwerator reverse power. Asubsequent S/G Hi Hi level resultedin an ESF actuation (TWI and AFWpumps startieg). The reactorentered Mode 2. Investigaticadetermined that the turbina EHCsystem was receiving anartificially high input for turbineimpvise pressure, caused by adampening vaYve that had vibratedclosed. Administrative (entroishave been initiated that prohibitthe ese of the turbine centrolcircuitry that utilized the turbineimpulse input. Unit 2 was tiedonline at 0415 EST J,ca ry S. 1998,and reathed 100 percent reactorpower level at 2303 EST enJanuary 7 1991.

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I 2 3 kshibit G-InstructionsF: Forced Reason: Method:5: Scheduled A-Equipment Failure (Explain) 1-Manual for Freparation of Data

B-ft+intenance or Test 2-Manual Scram Entry sheets for Licensse

C-Refueling 34utomatic Scram Event Report (LER) File

D-Regulatory Restruction 4-Continuation of E=isting Outage (NUREG-1922)E-Operator Training and License Examination 5-RedectionF-Administrative 9-Other

5 Exhibit I-Same SoorteG-Operational Error (Explain)H-Other (Explain)

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _