ML17286A748

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LER 91-008-00:on 910416,reactor Declared in Mode 5 (Refueling) W/Average Reactor Coolant Temp of 140 F.Caused by Less than Adequate Procedures.Temp Reduced & Upper Temp Limits Incorporated Into Plant procedures.W/910510 Ltr
ML17286A748
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 05/10/1991
From: John Baker, Fies C
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-91-093, GO2-91-93, LER-91-008, LER-91-8, NUDOCS 9105150329
Download: ML17286A748 (7)
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Text

ACCELERATED IQTRIBUTION DEMONSATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9105150329 DOC.DATE: 91/05/10 NOTARIZED: NO DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR. AFFILIATION FIES,C.L. Washington Public Power Supply System BAKER,J.W. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 91-008-00:on 910416,reactor declared in Mode 5 (refueling) w/average reactor coolant temp of 140 F.Caused by less than adequate procedures. Temp reduced G.upper temp limits incorporated into plant procedures.W/910510 ltr. $

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR I ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

I SIZE: 5 NOTES' RECIPIENT, COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 -

1 PD5 PD .1 1 D ENG,P.L. 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 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/LHFB11 1 1 NRR/DLPQ/LPE B 1 0 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICB 7E 1 1 RR/gKT/S~BS Dl 1 1 NRR/DST/SRXB SE 1 ' REG FILE~

PILE 02 01 1 1 RES/DSIR/EIB 1 1 GN5 1 1 EXTERNAL EGGG BRYCE i 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 I

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NOTE TO ALL "RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

'ULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 33 ENCL 33

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352 Docket No. 50-397 May 10, 1991 GOB 91-093 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 t

Subject:

NUCLEAR PLANT NO, 2 LICENSEE EVENT REPORT NO.91-008

Dear Sir:

Transmitted herewith is Licensee Event Report No.91-008 for the WNP-2 Plant.

This report is submitted in response to the report requirements of 10CFR50.73 and discusses the items of reportability, corrective action taken, and action taken to preclude-recurrence.

Very truly yours, J. . Baker (M/0 927M)

WNP-2 Plant Manager JWB:ac

Enclosure:

Licensee Event Report No.91-008 cc: Mr. John B. Hartin, NRC Region V Hr. C. Sorensen, NRC Resident Inspector (M/0 901A)

INPO Records Center Atlanta, GA Hs. Dottie Sherman, ANI Hr. D. L. Williams, BPA (M/0 399)

NRC Resident Inspector walk over copy 0

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NRC FORM Si56 V.S, NUCLEAR REGULATOAY COMMISSION APPROVED OMB NO. 31504)104 (669)

EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION AEQUESTI 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P630), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

DOCKET NUMBER (2) PA E FACILITY NAME (I I Washin ton Nuclear Plant - Unit 2 o 5 o o o3 710F04 TITLE (4)

ENTRY INTO REFUELING MODE WITH AVERAGE REACTOR COOLANT TEMPERATURE GREATER THAN 140 DEGREES F DUE TO INADEQUATE PLANT PROCEDURES EVENT DATE (5) LER NUMBER (Sl ,REPORT DATE (7) OTHER FACILITIES INVOLVED (6)

I+"'EovENTIAL ~F RlvrsroN OAY YEAR FACILITYNAMES DOCKET NUMBER(SI MONTH DAY YEAR YEAR NVMDEII:eye: NVMDER MONTH 0 5 0 0 0 le) 0 4 16 919 1 008 .0 05 109 1 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT 7 0 THE RLOUHIEMENTS OF 10 CFR (Ir ICntce ont or more Of rht follow'nff (Ill OPERATING HI()

MODE ID) 20.402 I 8) 20.405(cl 50.73(e) (2)(lv) 73.71(8)

POWER 20.406( ~ l(IIII) 50.36(el( 1l 50.73(el(2)(v) 73.71(cl LEVEL 0 20.405 I~ I ll) (9 I 50.36(c) (2) 60.73 (2) (v9 I OTHER ISptcrfy In Aorrrecr Derow coffin Teer, HRC Form 20.405(el(1 l(BI) 50.73( ~ )(2)(ll 60.73( ~ ll2)(vBI)(A) 366AI 20A05(e)(IIIN) 50.73( ~ I (2 50.73(el(2)(v) 8) (Bl

@9 <AM':. 20.405( ~ )11)(v) 50.7 3(el(2(((BI 60.73( ~ l(2)(el LICENSEE CON'TACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE C. L. Fies Com liance En ineer 50 937 7-CAUSE SYSTEM COMPONENT COMPLETE ONE LINE fOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANUFAC TVRER CAUSE SYSTEM COMPONENT MANVFAC TURER EPOATABLE TO NPRDS 5Pcn.

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.'cfr Pj@nI3@~<4 SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR EXPECTED SUBMISSION DATE 115)

YES Iif yN, COmPitrt EXPECTED $ (f64IISSIOff OA TEI X NO

't ABSTRACT ILimir ro 1400 guctg it.. epproximertiy fifrttn efnofe.rpect ryptwrirrtn Iingi IISI t

1423 hours0.0165 days <br />0.395 hours <br />0.00235 weeks <br />5.414515e-4 months <br /> on April 16, 1991, just prior to the start of detensioning of the Reactor Pressure Vessel (RPV) head bolts, the reactor was declared to be in Mode 5 ~

(Refueling) with the average reactor coolant temperature greater than 140 degrees F."

This is a violation of the Technical Specification Operational Conditions Requirements'1 isted on Table 1.2.

The root cause of this event was less than adequate procedures.

Immediate corrective action was taken to reduce the average reactor coolant temperature. Further corrective action will be taken to place the Technical Specification upper temperature limit in the plant procedures.

The event posed no threat to the health and safety of either the public or plant personnel.

NRC Form 356 (669)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 31500)OE .

(6$ 9)

EXPIRES'/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST: 60.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31604104I, OFFICE OF MANAGEMENTANO BUDGET, WASHINGTON, DC 20503.

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

YEAR SEOVENTIAL REVISION NVMSER N?X NVMSER Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 7 9. 1 0 8 0 0 0 2 OF 0 TEXT /l/ moro EOoco /T rooo/rod, oso oddidonel HRC Form 3664 'g/ () 7)

Plant Conditions Power Level -0 X Plant Mode - 4 Event Descri tion At 1423 hours0.0165 days <br />0.395 hours <br />0.00235 weeks <br />5.414515e-4 months <br /> on April 16, 1991, just prior to the start of detensioning of the Reactor Pressure Vessel ( RPV) head bolts, the reactor was declared to be, in Mode 5 (Refueling) with the average reactor coolant temperature greater than 140 degrees F.

This is a violation of the Technical Specification Operational Conditions Requirements listed on Table 1.2.

At 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> with the plant in Mode 4 (Cold Shutdown) the Shift Manager noted RPV coolant average temperature was approximately 112 degrees F. The temperature had been logged at 117 degrees F by the mid-shift crew and the Shift Manager was concerned about Technical Specification 3.4.6.l.d which requires a minimum temperature of 80 degrees F on the RPV flange and head flange when the bolting studs are under tension. The Shift Manager also anticipated a RPV flood-up would be required to cover the steam dryer in order to limit radiation exposure when the head was lifted. If the downward primary coolant temperature trend continued, the flood-up could cause the flange temperature to be close to the 80 degree F requirement. In addition, it it appeared that the time being taken to reach the point had been in previous refueling outages and could of detensioning was longer than give the flanges more time to cool down.

As a result of the above considerations the Shift Manager directed Plant Operators to increase the RPV coolant temperature at approximately 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> on April 16, 1991 by increasing the amount of coolant that bypasses the Residual Heat Removal

( RHR) Heat Exchanger (RHR-HX-18). The coolant temperature increased throughout the morning and peaked at approximately 157 degrees F at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br />. It was then decreased slowly reaching a value of approximately 150 degrees F at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />.

During the same time period preparation for detensioning'he RPV head continued following 'the guidance of Plant Procedure PPM 10.3.5, RPV Vessel Head Removal and Replacement. At approximately 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> a pyrometer temperature reading of 89 degrees F was taken on the RPV flange. At 1423 hours0.0165 days <br />0.395 hours <br />0.00235 weeks <br />5.414515e-4 months <br /> Mode 5 (Refueling) was declared, and detensioning was allowed to start. At that time the average reactor coolant temperature was 155 degrees F.

RPV head detensioning continued during swing-shift and was completed at 2257 hours0.0261 days <br />0.627 hours <br />0.00373 weeks <br />8.587885e-4 months <br />.

The average reactor coolant temperature stabilized at approximately 150 degrees F during this time period and the flange temperature increased to 100 degrees F. The non-compliance with the Technical Specification was not detected by the day-shift crew that initiated Mode 5 operation or the swing-shift crew that continued to support the detensioning operation. The error was detected by the mid-shift Shift Manager who recognized the Technical Specification definition of Mode 5 was exceeded.

NRC Form 366A (639)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (689) APPROVED 0MB NO. 31500)OE r

EXPIRES: 1/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPI.Y WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REOUEST: 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (F430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (3I50010E). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE 13)

SEOV ENTIAL REVISION NVMSER NVMSER 0 5 0 0 0 OF TEXT /I/ moro oaooo /r ror/vtrod, voo odd/a'ono//VRC Farm 36649/ (IT)

Immediate Corrective Action Immediate corrective action was taken by the mid-shift operating crew to reduce the average reactor coolant temperature by decreasing the amount of coolant that bypasses the RHR Heat Exchanger (RHR-HX-l,B). The plant was cooled down to less than 140 degrees F by 2338 hours0.0271 days <br />0.649 hours <br />0.00387 weeks <br />8.89609e-4 months <br /> on April 16, 1991.

Further Evaluation and Corrective Action A. Further Evaluation This event is being reported per the requirements of 10CFR50.73(a)(2)(i)(B) as

".....Any operation or condition prohibited by the plant's Technical Specifications....H

2. The root cause of this event was less than adequate procedures. None of the procedures associated with the operating mode change mentioned the 140 degree limitation in Technical Specification Table 1.2.
3. An evaluation was performed to identify which procedures require modification.

Plant procedure, PPM 1.3.40, Operating Mode Change Notification, is used to verify all of the required surveillances are done prior to changing from Mode 4 to Mode 5 (or the reverse). This procedure may be completed and signed off long before the actual start of head bolt detensioning. As a result, it was concluded that adding the upper temperature limit requirement to this procedure would not provide an effective barrier to reoccurrence. Three other plant procedures identified below under Further Corrective Actions will provide this protection.

4. Further evaluation confirmed the lack of a specific reference to the temperature limit in the Plant Procedures. The only indirect reference was in the form of a "NOTE" found in Plant Procedure PPM 1.3.40, Operating Mode Change Notification, which reads, "Definition of modes may be found in the Definitions section of Technical Specifications."
5. There were no structures, components or systems that were inoperable prior to the start of this event which contributed to the event.

B. Further Corrective Action

1. Plant Procedure PPM 10.3.5, Reactor Vessel Head Removal and Replacement, will be revised to include a sign off step prior to the start of detensioning to verify the RPV coolant temperature is below the 140 degree F limit.

Additionally, the 140 degree F upper temperature limit will be added to the HLimitations" section.

NRC Form 366A (6J)9)

1)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (649) APPROVED OMB NO. 31500(04 EXPIRES: 6/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST.'00 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1NE PAPERWORK REDUCTION PROJECT (3(500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

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

'Ngm SEOUE.NTIAL P~l REVISION N: NUMSER .i'+: NUM ER Washin ton Nuclear Plant -'nit 2. 0 5 0 0. 0 3 9 7 9. 1 008 0 00 4 oF0 4 TEXT /I/ rmoee epecm /e rmqu/red, uee edd/rr'one/ HRC Forrrr 366A3 / (17)

2. Plant Procedure PPM 7.4.4.6.1.1D, RPV Head Tensioning/Detensioning Temperature Surveillance, will be revised to include the upper coolant temperature limit (-140 degrees F) for operation in Mode 5 while head detensioning is in progress;
3. Plant Procedure PPM 7.0.2, Shift and Daily Instrument Checks (Mode 5), will be revised to include monitoring RPV Coolant temperature and the Technical Specification -limit of 140 degrees F.

Safet Si nificance The'tandard Technical Specifications for General Electric BWR-6 Plants (NUREG-1434) issued by the NRC in January 1991 have removed the 140 degree F coolant requirement for Mode 5 operation because there is no accident condition postulated during refueling that takes credit for moderator temperature. This would also apply to BWR-5 plants such as WNP-2.

The higher coolant temperatures could result in a radiological concern if the primary system were open to the Reactor. Building atmosphere. During the time period that the temperature was high the Standby Gas Treatment (SGT) System was available if it had been required. However, since the reactor vessel head remained in place while the temperature was above 140 degrees F there was no increase in the evaporation rate of primary coolant to the Reactor Building atmosphere.

In conclusion, there was no safety significance associated with this event.

Similar Events There have been no'imilar events involving temperature requirements associated with mod changes. LER 86-005 was written when Mode 5 was entered without all required survei llances performed. The procedure changes generated to correct this problem did no identify the 140 degree F requirement.

EIIS Information Text Reference EI IS Reference

~Sstem ~Com onent Reactor Pressure Vessel (RPV AC VSL Residual Heat Removal Heat SO HX Exchanger 1B (RHR-HX-1B)

~

Standby Gas Treatment (SGT) BH NRC Form 366A (649)

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