ML070680178

Completed CAR 91-063, 10/26/1991

ML070680178
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	10/29/1991
From:	- No Known Affiliation
To:	Office of Nuclear Reactor Regulation, NRC/OGC, NRC Region 1
References
CAR 91-063
Download: ML070680178 (100)

Text

...... . .' .. . 1 1 'P P $ 4 OPERATING EXPERIENCE INFORMATION RBVIEW -\

TE: 10/16/91 ,

1

> TO  : CAPPUCCIO FROM  : BUTEAU

SUBJECT:

CASEGORY A COMMITMENT REVIEW Attached is a copy of commitment: CAR91063 This document i s being assigned t o you f o r assessment of its importance I

to safe plant operation and for specific action as indicated in the Additional Instructions below.

Please review the commitment, carry out additional instructions, and complete the lower portion of this form.

w e B Colmnitment DEVELOP CORRECTIVE ACTION REPORT TO ADDRESS MS-77 PACKING LEAK RESULTING ?N WATER CONTAINING f131 & I133 ON REACTOR BUIGDLNG FLOOR.

SEE PRO91-069.

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SUBMIT THIS COMPLETED FORM AND OTHER RFSULTS OF YO REVIEW TO THE I OPERATING EXPERIENCE COORDINATOR (OEC) BY 11/30/91

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Additional Corrective Action Process per W -msrkctive Action Guideline i

I sig. [-I Routine CAR [d ' NCR 1-1 None 1-1 I

- /Item is complete, well documented; no further tracking required.

- .- Additional commitment tracking; required; initiate the following commitment(s) and due date(s).

AaJ-enQ\ 4 hew U\q 3FX9Ib562

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! - fItem needs add'l closeout; DH to present o r final closeout.

H) Enter date presented:

) Final closeout received: bI4-f

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OPERATING EXPERIENCE INFORMATION REVIEW DATE: 1 1 / 2 3 / 9 2 I

TO  : CAPPUCCIO FROM  : BUTEAU

SUBJECT:

CATEGORY A COMMITMENT REVIEW I

Attached is a copy of commitment: PFI916502 This document is being assigned to you for assessment of i t s importance to safe plant operation and far specific action as indicated in the Additional Instructions below.

Please review the commitment, carry out additional instructions, and complete the lower portion of this form.

Type B Commitment INVESTIGATE CAUSE OF WATER POOL NEAR PRIMARY CONTAINMENT WALL. PROVIDE CORRECTIVE ACTIONS.

THIS ITEM TRACKS CAR91063.

- Item is complete, well documented; no further tracking required.

i - J Additional commitment tracking; required; initiate the following commitment(s) and due date(s).

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T-.G ,3:3si insgections aerf3rmed on 9 / 2 9 / 3 1 by bclrcscope identify z a a r zhe sar?d c i i s h i o n is aDparentiy ;:ompactea and 3 gap of approx.

. 4 ' s x i s ~ s becween t h e ccsnion and the Crywell. IF. addftlCR,

a. ~ .~ r rh.3 f

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i n i:.ls_rjertion

~ the sand was f u r t h e r observed to be extrenely d r y a s e*.:i,iie.ncsa by "piumGs 05 dzst" generated b y che inspection cqc :;men c.

.<~:~:e t h i~a a k \;as eva:Qated t c r %e relatively s h o r t in d u r a t i o n 30 inmediare .ccrrDsi:sn pocenciai or concern is identified. I t i s

jierGrare cancluded t h a t the 5mail leakage that existed did, n o t a;~;orse1y a f f e c r t h e concainment s c r x t u r a i m z e g r i t y .

May 1991 Revision O

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corrective Action Guiddine Page 3 A. Problems discovered through the corrective action process need to be evaluated as routine or significant. A significant ifem requires corrective action to preclude recungnca. The following are the definitions of routine and significant.

A condition adverse to qudity which could or bas affected plant safety or reliability or is a condition which constitutes a breakdown in &heQuality Assurance Program. Violation of Technical Specifications, regulations, or applicable standads constitutes a significant item.

The following events and symptoms rnw be reviewed with the above definition to determine if a significant CAR is warranted:

Events: Potentially Reportable Occurrences (FRO'S)

QA Audit Deficiencies, Level 1 QA SurveilfanceDeficiencies FireNPDES Violations NRC VioIatious Symptoms: Any departure from the conditions of the operating license

. or pennits required to support plant operation Any unplanned engineered safety feature actuarh including reactor protection system actuati~u C Any event or plant condition which requires notidcation to the NRC Operations Center rn Repetitive failures which have significant operational impact Failures of safety related components that may have generic implications Review of the above information may conclude that tbe mafter is more appropriately handled as a routine item and assigned as such.

.A significant item requires all nine elements of the corrective action process be completed in addressing &e identified issue. All nine elements are addressed by preparing an LER, NCR or significant CAR.

An adverse condition which appears to be an isolated event and not symptomatic of other conditions and therefore l e d to a significant item. These item typically do uot pose any immediate concern to safety or reliability.

The folkwing types of items must be reviewed against the above definition to determine if a routine CAR is appropriate:

QA Audit Deficiencies, Level 2 L QA Audit Observations, Level 1 8 NRC Unresolved Items

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ROUTINE CORREtTiVE ACTION RE?ORT (Sample)

SECfiGN 1 - CAR PREPARATiON Or i g i nac ifig Department f i- fk4 ~ CAR Number 7/-&.3 Descriptioii o f Problem:

- I Corrective Actions:

immediate and Short Term Corrective Actions:

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ArrDarent Cause &termination:

I Additional Corrective Action Recommendations: $ G&Kdf&+

I I Originator DPD&MA SECTSOW 2 - REVSEW/APPROVAL L

Department Supervisor Revien/Approval #&G2% 1 ,/I26 i

WAPf 0007.02 (Sample)

AP 0607 Rev. 1 i?@d.

Page 3 of 1 7

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- TASK TEAM FINAL REPORT -

CONTAINMENT PEDESTAL LEAK ReleasWApproved for the Task Team by:

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- Dennis Girrior, Senior Mechanical Engineer; Team Leader

- Tim Drouin, Mechanical Engineer Van Bowman, Operations Planning Coordinator

- Rich Booth, Mechanical Engineer, Maintenance

--Jim Fitzpatrick, Senior Engineer, Yankee Nuclear Services Division Frank Helin, Proect Engineer, Corporate Engineering Support Department Steve Skibniowsky, Chemistry Supervisor (part-time)

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Conclusion:==

It is concluded that .the source of the water leaking out of the concrete pedestal under the drywell is outside containment and the integrity of the containment is intact. The source of the water leaking out the concrete pedestal under the drywell is condensed steam from the packing leak on main steam line drain valve MS-77. This conclusion is based on the reduction in flowrate and 1-133 concentration which has occurred during the time since the leakage - of MS-77 was directed away from the containment shell.

The path this leakage was taking is suspected to have bypassed the transition sand volume. It is postulated that due to the very low volume flow rate, water would cling to the surface of the containment or concrete and pass through the sand transition area thereby never reaching the sand drain tines. A sketch of the sandkontainment interface (Attachment 1) shows a gap of approximately 3/4 between the sand and containment, which would allow water to flow, clinging to the steel containment, to bypass the sand. After bypassing the transition sand the flow path through the concrete pedestal is indeterminate. The most probable path is that the water reached a small crack or a cold joint existing between concrete pours and followed these cold joints through the concrete pedestal until it flowed out of the surface cracks in bays 2 and 12.

Residual Effect on the Containment:

For this leak there is no concern regarding the moisture between the concrete containment base and the steel containment. The basis for this determinatiion is a follows:

1) Only a very small amount of leakage was identified, the maximum ieakage rate was identified to be approximately 260 rnI/hr.

An operator on routine rounds identified this leak and promptly initiated further investigation. It is believed that this leak did not exist for a long period of time prior to discovery.

2) following redirection of leakage from MS-77, the reduction in ieakage flow was paralleled by an expected decrease in iodine concentration. Reductions in both flow and iodine concentration demonstrate that the flow path was free flowing. If a reservoir existed somewhere in the path it is expected that flow of water would continue at a near constant rate. A reduction in iodine

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concentration, from decay, would still be seed following isolation of the leak source. Without a reservoir as a source of water a short term leak would continue to drain to the same location and the rate of flow would decrease over time.

3) The sand cushion environment and the relative warm temperatures of the reactor vessel, containment and the forus area encourages drying. The recently completed boroscopic inspections did not identify any other source of moisture which would maintain or elevate humidity. An appreciable amount of ventilation exists throughout the area.

4) The sand drains were inspected in June of 1987 and identified to be clear and functional. No water has ever been observed draining from these lines. These lines did not have significant levels of contamination. Additionaf boroscopic inspections performed on 9/30/91 confirm that the drains are functional.

5) Inspections performed on 9/29/31 by borescope show the sand cushion to be compacted and a 3/4 gap exists between the sand ring and the containment. In addition, during the inspection the sand was further observed to extremely dry.

In conclusion, the leak was relatively short in duration and adequate drainage and drying exist. The total exposure time for any corrosion mechanism to act is very short. Therefore, no detrimentaf containment corrosion concern is expected. It is therefore concluded that the small leakage that existed did not affect the containment structural integrity.

Chronology:

Sunday

• Water was discovered by an Auxiliary Operator on routine 9/22/91 (once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) rounds. Water on the floor was traced back and determined to be seeping from a surface crack in the concrete supporting pedestal under the drywell, at bay 12 internal to the ring of the torus. No contamination was identified at that time. See Attachment 2 for details of the I

crack.

Monday

• The discovery of this water was identified to the Operations 9/23/9f Planning Coordinator on Monday morning. The Operations Planning Coordinator began to investigate the problem as soon as he was made aware of the issue.

• A sample of the water that had made its way to the floor was taken. This sample was found to be contaminated. Floor contamination levels were 30,000 counts per minute above background.

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Tuesday

• Mechanicaf Engineering was contacted for assistance to 9/24/9 i review the construction drawings in the area of the leak.

Following the drawing review the Operations Planning Coordinator performed a visual examination of the transition sand drain lines and did not see evidence of any leakage.

• Inconclusive Chemistry sample results were presented and discussed at the morning OPS Planning meeting. The OPS Supt. and NRC Resident were in attendance.

• A second sample was taken, this time from the water on the wall. The results of this sample were also suspect due to surface contamination of the wall. The sample results were inconclusive, regarding the source of the water.

• The Operations Supervisor was briefed by the OPS Planning Coordinator. It was recommended that a more accurate sample be taken.

Wednesday 912519 1 The Operations Planning Coordinator reviewed Generic Letter 87-05 and related documentation including the VY closeout. The closeout of the GL package indicated that the sand drains at VY were clear and functional. The Operations Pfanning Coordinator requested an uncontaminated sample with some conclusive results be taken to provide additional information regarding the source of the leakage.

The leak from the pedestal was sampled at approximately 1330 and 1-131 and 1-133 were measured, conclusively.

Thursday

• 9/26/9 1 The pedestal wall in this area was decontaminated and another sample was taken. The results of this sample indicated some isotopes found in reactor coolant water. The concentrations of iodine in the sample indicated that the water was 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> older than Rx Coolant based on the ratio of 1-131 and the decay of 1-133 ,however, the lack of other nuclides normally present in the reactor coolant stili made the conciusions unclear.

• Additional seepage of water was discovered in Bay 2 of this area by RP during surveys of the area. The flow rate of this crack was less than the flow rate at Bay 12. See Attachment 3 for locations of Bays 2, 12 and MS-77.

Once these results were reported, the Operations Planning Coordinator contacted John Herron, Operations Supervisor and the issue was raised at the afternoon PORC meeting. At 1630 following the PORC meeting the Operations Supervisor informed Bob Wanczyk, Operations Superintendent of the problem and he contacted Bernie Buteau, Engineering Director for assistance.

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• Supbsequent to the request for assistance the Engineering Director met with the ME&C Supervisor and decided to form a multidisciplined task team to address the problem.

• In addition, A.D. Himle of General Electric was contacted and he in turn confacted the GE lead systems engineer for containments and a search for similar problems was put out on GEs world wide computer bulletin board.

Friday 9/27/91

• The Task Team was formed in the morning, an initial meeting was held at 1330. The immediate task of the team was to determine the state of containment integrity.

Since the source of the water was unknown the team was directed to attempt to quantify the leak assuming the worse case, that leakage was through the containment, in terms of the Technical Specification limits. A calculation was performed by the Mechanical Engineering Group to convert a water leak at 2 psi in the containment to an air leak at 44 psi. The results of this calculation were independently verified by YNSD and concluded that the containment still met the Technical Specification requirements for integrated leakage. [See Attachment 41 At 1400, the NRC Senior Resident Inspector was formally notified of the problem.

At 1600, a telecon was held with NRC Region 1 management, to discuss the problem and present the results of the calculation. During the telecon the NRC expressed concern over the leakage and the possibility that reactor coofant could be making its way out of containment. The NRC urged an active effort to identify the source of the leakage. The NRC was assured that the task team was scheduled to work over the weekend to investigate the problem. It was agreed that a telecon be held Monday morning to discuss the weekends findings.

• The task team was scheduled to be in Saturday morning to continue the searcb for the leak. The effort to get the boroscopic examination team on-site at the earliest possible time was expedited.

CTS was contacted by the Task Team to supply VY with a Boroscope Inspection crew. The crew was originally scheduled to arrive Monday morning. This was expedited to Saturday evening.

The Shift Supervisor was fully briefed on the situation.

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Saturday 9/28/9 1 The team met at 0730. The first task of the team was to walk down and visually inspect all accessible containment penetrations, beginning with the torus penetrations. The scope of the inspection effort was to visually inspect each penetration for signs of moisture leakage at that penetration as well as examining the containment wall for signs of leakage down the containment wall from a penetration above the one being examined. This gave maximum inspection coverage to the containment wall.

• A sample of the leakage in Bay 2 was taken at 0800. The result of this sample showed 1-133 concentration to be slightly greater than the concentration in the Bay 12 sample. This indicates that the travel time to this leak is shorter than the travel time to the Bay 12 leak, Bay 2 is closer to the MS-77 valve so this is consistent with the teams finding.

At 1010, during the visual examination of the torus penetrations a packing leak was discovered on valve MS-77 (Main Steam Line Drain Line) valve. A portion of the condensation from this packing leak was dripping on the drywell ventifation supply line and was running down the Iine to Penetration X-26. This line has a downward slope of 15 degrees toward the containment. This penetration is also the only penetration which is pitched down to the containment.

A like potential with other penetrations is significantly less.

Water running down this pipe was reaching the drywell and running down the exterior of the steel containment. This penetration is located above bay 3. See penetration detail on Attachment 5.

NOTE: The packing leak on MS-77 was initially reported on 6/4/91, and MR 91-1367 was written. However the packing leak stopped shortly thereafter and the MR was left open to repack the valve at a later date. Shortly following the reactor startup on 6/16/91 the packing leak was again reported to the Operations Planning Coordinator. This leak was also expected to stop shortly after startup.

• A sample of the MS-77 leakage was taken at 1022. S.

Skibiniowsq, Supervisor, compared results of this Chemistry sample to t e results o the sample of pedestal leakage. This comparison revealed that the source of the leakage could be this packing leak. It was further determined by this comparison that if this were the source of the leakage it was taking about 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> for this water to migrate to the bay 12 pedestaf area. [Attachment 61

• At 1100, the leakage from the MS-77 valve was redirected by Maintenance Department personnel, in an attempt to stop the leakage from running down the drywell ventilation supply pipe and reaching the containment wall.

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Following the redirection of this leakage the team recommended a sampling pro ram to measure both leakage 9

rate and iodine concentration evels be instituted.

The visual examinations on the remainder of the containment penetrations, with the exception of the folIowing unaccessible areas: Steam Tunnel, and Cleanup Phase Separator Room, continued in the afternoon. These inspections were completed at 1530 and failed to reveal any evidence of moisture leaka e on any other containment 3

penetrations or other areas o the Containment wall.

• The boroscope examination vendor (CTS) arrived on site at 1900 and began preparations for conducting boroscope inspections of the containment walls and the transition sand drain lines.

Sunday 9/29/9 1 The results of the sampling program show the leakage and P

the concentration of 1-133 aff-life of 20.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) began dropping soon (within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after the flow from MS-77 was directed away from containment. 1-131 is a longer lived (half-life of 8.04 days) iSOtOp8 and would therefore not show the same change in concentrations as 1-133. These results are consistent with what one would expect if the source of the leak had been cut off. The activity levels drop along the decay curve showing that the source of water for the leakage no longer exists. [See Attachment 7]

I Monday

• The results of the sampling program show the leakage rate 9/30/91 to continue to be decreasing.

Boroscope inspections of the area between the sand ring and the drywell reveal no residual moisture. The sand does not contact the steel shell and is dry.

Boroscopic inspection of all 8 sand drains show no indication of new or recent leakage. The conditions of these lines are verified as being unchanged from the inspections performed in 1987.

I The leak stops at 1800 hrs.

• A review of the video tapes by the team reader and YNSD confirm that the drywell shell is not suffering corrosion due to this or other leakage. There is no visual indication of excessive scale or pitting.

Tuesday 1O i l 191 The ptask force met with plant management (RJW,BRB,GC) and informed them all inspection activities are complete.

Outstanding items were discussed and a critique of the task force performance was provided.

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Recommendations:

Repair the MS-77 packing leak at the first opportunity. .4 Operations Dept. should perform weekly surveillance on the torus inner 4" diameter. v

3) Although we determined the problem to be external to the containment a requirement io visually inspect the area at the intersection between the containment wall and the concrete floor inside the drywell should HE?'

be added to a drywei! inspection procedure.

The plant should consider installing a "cone" type barrier on the penetration that slopes toward the containment to prevent any future nnA.'y\i water leakage from reaching the wall of the containment.

Review Vermont Yankee response to Generic Letter 87-05 and n~'n c determine if a revision is necessary.

Review the BWR Owners' Group letter to NRC of 12/22/89 and ME; c determine if any further actions are appropriaie.

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VERMOMYANKEE NL'CLEAR WWEA P.0.BOX 157 SUBJECT PREPARE0 B Y CHECIKD B Y REVIEWED

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. r VERMONT YANKEE NUCLEAR WWER CORWRATION P.0.BOX 157 I S VERNON. VERMONT 05354 DATE PAGE NO.

SUBJECT PREPARED B Y CHECKED BY REVIEWED I

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h. VER MONTYANKEE KUCLEAR POWER COAPORATION.,

P.0.BOX 157 VERNON. VERMONT 05355 REPORT DATE PAQE NO.

SUBJECT

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I PREPARED BY CHECKED B Y REVIEWED .-

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MEMORANDUM To : T-ASI; G R X P .-- - 'I'ernon V.Y. Sate 9/29/91 From: G . C=\-PPCL'cCIO ' ---

V . I-. Vernon . F i l e : 3.1 Subject : L E - U CALCULATIO?;

ISTRODUCTIGN 9/27'1$1 6 ' % @ i C E R 3 I4-G RIISED AS TO THE STATE OF COXTAIhiEXT OS THE V>.LL MOISTURE/LEAK EISCOVERED LX.THE TORUS ARE&. SINCE THE SOGRCE OF THE 1,EAKAGE k4S UKKNOkT, THE WORST CASE SCESARiO WAS ASSUMED W I C H WAS THE LEAKAGE WAS COMIWG FROM THE PRIX4RY ZONTAIXblENT. TO ASSESS THE ST.4TE OF C@NTAI35fEArT, d CALCGLATIOM W-4S PERFORYED TO FIKP AN EQCIVALEYT HOLE AND THEN RECALCGLATE THE LEAILAGE'-AT .$CdlDENT COSDITIONS.

FHfiPl 'I'HE .WOLi&T OF NEA4SURED WATER COMh'G FROX THE HOLE, A ORIFICE WAS CALCLLXTED ESIXG A CGMPGTER PROGRAM, THE CONDITIONS EXTEREP hRfi AS EOLiOWS:

I ) THE LE.XAGE MAS MEASCHED AT 22DmL/HR. FOR TH'E CALCULATIOX THE U T E VAS DOtiBLED, C.llffiuL/RR).

2: -4 PRESSURE OF 2 P S I VAS USED .AS T"HE d p . TGIS VAS COSSIBEHED COKSERVATLVE COKSIDERIKG T'UT IF THE LE4K VAS CO?fIXG FROW YI3E DRk%7ZLLt, THERE KAS A MI'E;IMJM OF 12 FEET OF S'I'ANDISG HEAD 1K A D D X i I O N TO THE DRYWELL PRESSURE.

A F i E 3 TdE ORIFICE WAS SIZED , f O R LIQUID, a CALCULATION %AS PERFORMED TO DETERMIKE THE ANOGXT' OF AIR 'GiZTICH COELD BE PASSED lHROUGH THIS HOLE AT ACCIDENT COKDITIONS.

UP05 FXSDISG THIS BULVTITY, THE LEiXAGE %AS SUPERIXPOSED ON THE YRESENT/LAST APPENDIX J TYPE A TEST, THE RESULTS OF THE C-4LCULX?IO?i SHOWED THAT THE COXTXIXMENT STILL MET THE TECHKICAL S P E C I F I C A T I O N REQUIREMEKTS FOR INTEGRATED LEAKAGE.

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FLOWRATE. LBS/HR . 2 3 13702 FLOWRzITE .4CF?I 1.289689E-02 FLCID STATE GAS GRIFICE DItLVETER, IXCHES .DO9 P I F E L I K E DIAYETER, ISCHES

• 622 ORIFICE/PIPE DIA RATIO 1.446945E-02 ORIFICE TAFS F LXNGE IXTERX.4L AREA, SQ IPi, . 6.361739E-05 DEXSITE'. LBS/CUBIC FT. .299

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'I'ISCOSI Tk- CENTIPOISE TEMPERATURE. DEG.F.

,018 70 UPSTREAM PRESSURE, PSIG 41 FLOW COEFFICIENT ,5890159 ORIFICE COEFFICIENT .5890159 EXPAhSION COEFFICIENT ,7076517 SPECIFIC HEAT RATIO 1.4 ORIFICE REYNOLDS NO. 9812.013 PRESSURE DROP. IXCHES H20 1218 PRESSURE DROP. PSI 43.92355 PERMAlt'ENT

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P S I LOSS 43.91435

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O R I F I C E SIZING StmMARY 11111111~111R=R11111===-=-~-~-=====-=Ru=~==-===~~-=R=--~~~---==R I VATER LEAKAGE THRU 1/2 D D l l t P O I P P P I I R ~ ~ I ~ I I ~ m = 1 ~ ~ ~ = ~ ~ = ~ R R ~ ~ m ~ ~ ~ m ~ ~

FLOWRATE GALIMIN .002 FLOVRATE. LBSIHR . 9 8 6 128 F L U I D STATE LIQUID ORIFICE DIAMETER, INCHES 9.093419E-03 PIPELINE DIAMETER, INCHES *5 ORIFICE/PIPE DIA RATIO 1.818684E-02 O R I F I C E TAPS FLANGE INTERNAL AREA, S4. IN. 6.494493E-05 DENSITY. LBS/CUBIC FT, 61.633 VISCOSITY, CENTIPOISE ,511 TEMPERATURE, DEG.F. 125 UPSTREAM PRESSURE, PSIG 2 FLOW COEFFICIENT ,5875462 ORIFICE COEFFICIENT ,5875482 ORIFICE REMOLDS NO. 1339.105 Ubr' .c 2PC'Y PRESSURE DROP, INCHES H20 52 *r-* A d PRESSURE DROP, PSI 1.875225 J c ~ T R for,,.

p ,/M PERMANENT PSI DROP 1 874605 *#It.

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MEXORkhJDUM

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To : B R BUTEAU t.F. Vernon -

Date 9 / 2 7 / 9 1 From: G . CXPPT,CCIO V. 1. J.-ernon File: 3.1 Subject : T-ASX FrJRCE TEE FURPGSE 3f TiIIS.?IEMO IS iG PRCiVIDE THE CUiDAKCE T?i RESL?ir;iSG THE CLRREKT ISSUE OF MOISTURE OH iHE COLVTAI?,?fEPIT SCPPORTISG BASE.

INTRODUCTION RECESTLY. THE OPERATIONS DEPARTMEST IDESTIFIED >OLSiLiRE 43XCH V-LS V E E P I X G X T OF THE CONCRETE VALL LOCATED ~ ~ P P R O I I ? l 4 T E L E -4 FEET ABOVE THE TORUS LEVEL, SOCTH EAST DIRECTION. SIXCE THE L E U IS VERY SX4LL. THE SOURCE KAS SOT BEEK IDEYTIFIED. TO RECTIFY TITIS PROBLEM, 4 TASK GROUP WILL BE FORYED TO I-YVESTIGATE THE iSSUE AND PROVIDE FIHDIYG AYD RECOMPlEKDATIONS BY 1pI/4/91, TASK FXPECTATIONS T-4SK GROUP IS EXPZCTED TO PERFORM TRE FOLLOWIMG TASKS, IDEIGTIFFY XZAWS OF DETERXING THE SOURCE OF THE LEAKAGE BY FRIDAI- OCT, 4TH.

k3ITE S . BMO AVD PRESEXT TO POBC SEPTEMBER 30.

DEVELOP A CORRECTIVE ACTION PLAN AK-D U S E 13607 AS A STARTING POIST -L%D FISALIZE BY OCTOBER 1STH.

EZjSURE THAT BLL EQGIPMEKT .LiD SOFTWARE IS AVA1LA4BLE TO PERFOR3 A T Y P E A TEST. IDENTIFY AXY PURCHASES.

THE GROUP IWST PERFORM A THOROGGH INSPECTION OF THE WALL. TIIIS INCLUDES (BVT IS XOT LIMITED TO), THE CO3STRUCTIOX DRAIXS, S.%Hl RIWG DRAINS, POUR LIXES ETC. ADDLTIOKALLY, THE GROC?

SHALL USE ORIGINAL COXSTRECTION PfCTGRES, CB&I DR4VXFiGS, >i&K DRAWINGS, ETC .

THE GROGP &%ST C O N T A C T RP FOR HWPs AND TOCCH BASE CITH ANY OTHER SUPPORTIYG DEPARTMENT FOR SERVICE. IF .4 DEPARTMEXT CAXNOT SUPPORT YOUR REQUESTS, r ,WST BE CONTACTED IHMEDIATELY.

THE GROUP NUST CONTACT OTHER SIXILAR BkXs TO SEE IF THIS PROBLEH HAS OCCURRED ELSElrHERE.

THE GROUP SHALL CONSULT IXDUSTRY I N F O ~ 4 T I O ~ ASOURCES L SUCH AS XFRDS, I N P O , E P R I , SEARCH, ETC. Opr THE ISSUE.

THE GROUP SHALL PROPOSE .4NY TEMPOWRY OR P E M 4 K E N T F I X E S .

10) THE GROUP SHALL MEASURE THE AMOUNT OF LEAKAGE AYiD FOWULATE TliE EQUIVALENT ORIFICE SIZE.

11) REVIEW THE RECENT VCR TAPE OF THE LOWER LEVEL OF CONTAIiXMEXT FOR CLUES.

12) COMPARE ACTIVITY OF F L U I D WITH OTHER SAYPLES k;HfCH CHEMISTRY TAKES TO DETERMIKE IF THE SOURCE OF WATER CAS BE ISOLATED.

IMMEDIATE TASK BEFORE 1800 9/27/91 IDENTIFY kHETHER PRIM.4RY CONTAIPMENT IS I N QUESTION.

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. ., .. .. _., . .. ... . MEMORiWDUK' ".'

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REPORT THE GRQL'P LEADER WILL PROJ'TDE PROGRESS REPORTS AT 9.4-Y .43D AT 3 E l DAILY TO GC. THESE REPORTS'SKALL STATE THE PROGRESS OF THE ABOVE ITEMS -AS LISTED.

SCBEDULE THE TASK GROVP WILL WORK THIS WEEIiEBD SEPTE?fBER 2 8 6L 2 9 , XND REQUIRED OVERTIME TO S'GPPORT THE PROPOSED SCHEDULE FOR COMPLETION, THE HA.X.AGE.clEXVT HAS RECOGYIZED OVERTIME FOR iHIS PROJECT. THE GROUP WILL fJLTI-YATELY REPORT TO ME.

i EKGISEERING DIRECTOR

-

cc DAR i

RJV RDP DEPT. HEADS TASK GROL-P

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A Root Cause Analysis of t h i s event was performed. It was determined that the root cause of the event was a deficient design and design review performed daring original construction.

The s u b j e c t PCAC p e n e t r a t i o n is the only containment penetration with a downward slope to the containment. The placement of MS-77 directly over t h i s pipe allowed leakage from the valve packing to travel down this p i p e and contact the drywell shell.

I t is not unexpected that valve packings will leak, especially in high pressure - high temperature service. The location of MS-77 directly over the negative sloping PCAC pipe is identified as a poor original plant design and d e s i g n review. Root Cause Analysis Items D12 and E31 are identifed as the root cause(s1 for t h i s event.

A "checked-off" Appendix C to Ap 0007 and RCA Flow Chart is attached-i 32

APPENDIX C (Continued)

ATTACHMENT 3 I T h i s charting EXPLANATION OF THE OECISION TREE AND I T S USES method i s used for logically displaying the f a i l u r e and I

ilSustrating i t s causes, Charting a l s o helps' identify where corrective actions are needed.

The decision t r e e has various l e v e l s of detail from t h e top of the tree (feast d e t a i l ) to t h e bottom of the t r e e (most d e t a i l ) . The decision tree i s labeled with alpha-numeric codes which correspond t o each category o f t h e decision tree. Recommended questions f o r each category can be found i n t h i s guideline, The investjgator wilt decide i f a category i s :

AOEQUATE, INADEQUATE, NOT APPLICABLE, 1

,

NEEDS MORE INFORMATION {prior t o coding as ADEQUATE, INADEQUATE, or NOT AfPLICABLE)

Once the question is answered and the block is coded, move to the next block down t h e tree, The root cause(t) and/or contributing causc(s) a r e the blockfs) coded as INADEQUATE, The process is complete when the whole tree i s coded. Return to t h e User's Guide t o test and code t h e causes, see Steps 4, 5 and 7.

AI. NATURAL PHUOMENON/SABOTAGE Was a tornado, hurricane, earthquake, lightning, flood, or othec

-- natural phenomenon the cause of the failure? Were deliberate inten-tions or subversions rcspons4bla f o r the failure?

A2. WfWARC OtFFfCULTY (PROCEOURES, C m N l C A f I O N S , HUMAN FACTORS, TRAINING, MANAGEMENT SYSTEMS, IMMEDIATE SUPERVISION, QUALIM CONTROL, PERSONNEL ERROR)

Refer to SectSon D1 through 08 for further development under SOFTMARE OIFFICULTY.

Append{* C AP 0007 Rev. 1 Page 12 of 2 1 i

33

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APPENDIX C (Continued)

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NOTE A t this point i n the decision tree, there is a skip from level A to level D'because there are no level 8 or C categories under Section A2, SOFTWARE DIFFICULTY.

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02. PROCEDURES Was a procedure related difficulty (procedure not used, procedure fallowed incorrectly, o r procedure wrong or incomplete) i nvo 1 ved?

Refer t o Sections El, 2, and 3 f o r further developaent under PROCEDURES.

El. PROCEOURE NOT USE0 Was a procedure used to do t h e job? Was the procedure not available o r inconvenient for use? Was the procedure difficult to use?

If a procedure was available but not used, the event should also be dual coded under Section 14, PROCEDURES, POLICIES, or AOMfHfSTRATfVE CONTROLS NOT USED, because the procedure or policy t o use procedures to perform all work was not used.

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E2. PROCEDURE FOLLOWEO INCORRECTLY Was a failure caused by making an error while following or t r y i n g to follcrw a procedure? Was the procedure format confusing or different f m m t h e standard format? Was there more than one action per procedure step? Was the checklist misused?

• r e data computations i n t h e proce-dure wrong or incomplete? Were the graphics used in t h e procedure ina-dequate? Was equipment identification inadequate? Were the procedure steps ambiguous?

NOTE Some errors in following pracedures should also be dual caded under Section 14, STANDARDS, POLICIES, OR A O n m r s t R A T r ~CONTRULS NOT USED.

Also. some causes nav be dual coded under Section 04, TRAINING, if additional trainjig was needed t o successfully complete the procedure.

c-c-------~------"--~"-~-

3. PROClOURE WRONG/iNCOMPLETE Was a procedure incomplete or wrong or d i d i t fail t o address a situation which could occur? Was a typographical error in the proce-dure responsible for the failure? W a s there an incorrect sequence of steps in the procedure, even though the correct information was pre-sent? Was the wrong revision o f a procedure being used?

Appendtx C AP 0007 Rev. 1 Fag8 19 af 21

APPENDIX C (Continued)

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D2. COMMUNICATIONS Was an error caused by nisundecstood verba7 communication or 7ack of communication? Refer to Sections 4 , E5 and E6 f o r further development under COMMUNICATIONS.

Ed. MISUNDERSfOOO VERBAL COMMUNICATION Was a f a i l u r e caused by misunderstood verbal or o r a l communications b e t -

ween personnel? Was a communication error caused by failure to repeat back a message t o v e r i f y t h e message was heard and understood correctly?

Was a message o r instruction misunderstood because it was too long and should have been written instead of oral?

~ 5 . NO COMMUNICATION OR NOT r r m y Was a failure caused by failure to communicate o r by communicating t o o late? Was no cummunication ever made because no method o r system existed for communication? Were communications provided too late I because events happened too fast to al'low time for ccmnunications?

6. SHIFT TURNOVER INADEQUATE Did incorrect, incomplete, o r otherwise inadequate s h i f t turnover occur?

03. HUMAN FACTORS Was an error made because of poor or undesirable h a a n factors engineering?

Refer' t o Sections 7 , E8, 9, and El0 f o r further developncnt under HUMAH FACTORS.

7. MAN-MACHINE INTERFACE

--

Was a failure caused by poor coordination or interaction o f personnel with the equipment, systems, facilities, or instrumentation with nhich they work? Uid labeling fa51 to clearly identify OF d i d labeling incorrectly identify equipment? Did poor arrangeaent o f equiprant contribute to causing t h e failure?

Did differences i n equipncnt o r equipment controls betmen the plant and simulator Control Rooms contribute to t h e failure? Did inadequate or unclear instrument gages, djsplays, o r equipment controls contribute to causing the failure?

Appendix C 4? 0007 Rev. 1 Page 14 o f 21

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APPENOIX C (Continued)

Was the work environment not conducive to good human performance (such as poor housekeeping, inadequate lighting, o r excessive noise]? Oid high r a d i a t i o n contribute to the failure by causing personnel to hurry work to reduce exposure o r by requiring protective clothing that dimi-nished performance?

E9. COMPLEX SYSTEMS Was a failure caused by the system o r equipment controls being complex or compl icated?

E10. NON-FAULT TOLERANCE SYSTEM Were errors undetectable before a failure or event occurred? Wrre errors not recoverab7e if discovered before a failure occurred?

p/ TRAINING Was a failure caused by lack of, incomplete, or otherwise inadequate training?

Refer to Sections Ell and E12 for further developcaent under TRAINING.

1. NO TRAINING Was there a lack of training to pepsonnel on a particular system o r subject? has no training offered because a task war performed so infrequently ( o r not expected at all) that training nas decided t o be unnecessary?

1. TRAINIHO FCET&X INAOEQUATE Were training methods such as testing, repeat training, facilities used, and thoroughness of trainjng inadequate?

The HANAGEMEIIT SYSTEM category refers t o problems in the adrinistratfve controls, the organization, or the system by which work +s controlled a d acconplished. This category represents problems which upper level management has control over and responsfbility to correct and i s not intended to reflect errors E m i t t e d by management but rather weakness i n the work control system. Management errors w i l l be treated the same as worker errors.

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Appendix C 4P 0007 Rev. 1 Page 15 of 21

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APPENDIX C (Continued)

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D5. MANAGEMEUT SYSTEM Did an error result because of inadequate standards, policy, direc-t i v e s , organizational ineffectiveness, or administrative control d e f i -

ciencies o r failure to use existing policy? Was implementation o f policy or directives inadequate? Was an event caused by failure to adequately correct o r to implement corrective actions of known malfunc-tions or deficiencies? Refer to Sections 13, 1514. ElS, and E16 for further development under MANAGEMENT SYSTEM.

E13. STANOAROS, POLICIES, OR ADMINISTRATrVE CONTROLS ( S P A C ) INADEQUATE Was a failure caused by inadequate standards, policy or administrative controls including drawings or prints? Were the SPAC confusing, incomplete/outdated, unclear, ambiguous or not strict enough, Were drawings or prints incorrect or not updated, or d i d t h e y not reflect as built conditions? ,.

Eld. SPAC NOT USED Were SPAC or directives not used, adhered to or Pollorred? Were stan-dards, directives, or policy not communicated from management down through the organization? Has enforcement of the SPAC in the past been lax? Mas an SPAC not followed because a method of implementation was not provided f o r the SPAC.

El 5. AUOETS/EVALUATIQNS Was a failure caused by, or can it be attributed to, inadequate audit or evaluation programs or f a i l u r e to provide independent audits or evaluations?

16. CORRECTIVE ACTION

-- Were r e c o d e d corrective actions for k n m deficiencies not imple-mented or installed (due t o delays i n funding, project design, correc-tive action imptenentation cycle, etc,) before recurrence of the deficiency?

06. IMNEDIATE SUPERVISION Was a failure caused by inadequate or lack o f immediate (first line) supervision during job preparation or during performance of the job?

Refer t o Saction E17 and E18 for further developsent under IMnEOIATE suPEwIsrm Appendix C A? 0007 Rev. 1 Page 16 of 21 c

APPENDIX C {Continued)

E17. PREPARATION Was a failure caused by failure of immediate supervision to provide adequate preparation ( i n c l u d i n g capable w r k e r s ) , job plans, o r walk through for a job? Was a failure the result of an incorrect switching and tagging order or a failure tu switch and tag all necessary equip-ment before doing a job? Was scheduling o f periodic tests, sutveillan-ces or Maintenance Requests inadequate?

18. SUPERVISION DURING WORK Did immediate supervision fail to provide adequate support, coverage, oversight or supervision during job performance?

07. QUALITY CONTROL (QC)

Were equipment malfunctions ar maintenance difficulties not discovered because of a failure to perform or adequately perform QC, functional t e s t s , post maintenance tests, o r quality verification checks during or a f t e r completion of work? Refer to Sections El9 and E20 for further development under QC.

EI9. NO QC Here QC checks, functional tests, o r quality verification checks during or a f t e r com~letionof work not required or not performed?

EZO. QC INADEQUATE Was an equipment malfunction o r difficulty caused by specifying QC, quality verification, o r functional testing that was not adequate or COmQrehenSiVe enough to detect possible errors?

D8. PERSONNEL ERROR

--

Caution should be used when selecting this category. There i s a poten-tial to mask other root causes under SOFTWARE DIFftCULTY and EQUIPMENT DIFFICULTY. T h i s would r e s u l t in inappropriate corrective actions and inaccurate failure trending.

21. LACK OF MENTAL ATTENTION Was an error caused by preoccupation, iltness, excessive overtime, horseplay or distractions?

22. MISINTERPRETATION OF INFORMATION Was an error caused by a lack of information, wrong information o r improper conrunScation of infarmlatim?

Appendix C AP 0007 Rev. 1 Page 17 of 2 1

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APPENDIX C (Continued)

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23. PROCEDURE NOT FOLLOWED Was an error caused by a worker electing not t o use a procedure?

24. INEXPE~IENCE/~NOECISION bias an e r r o r made due to a lack of experience or improper decision ma& ing?

A3. EQUIPMENT MALFUNCTION/DlFFfCULTY Did an equipment malfunction or equipment difficulty i n i t i a t e the fai 7 we?

Refer to Sections 81, EQUIPMENT MAINTENANCE (INSTALLATION, CORRECTIVE, PREOICTIVE AN0 PREVENTIVE, 82, EQUrPHENT RELIABLLIN/DESIGN, and 83, CO~SfRUCfLON/FABRICAtION, for further.development under EQUIPMENT MALFUNCTTdN/OIFFTCULN.

81. EQUIPMENT MAINTENANCE Was the failure initiated or a result of equipment maintenance activi-ties? Refer to C1 and C2, Cl . ~~STALL&TIDN/CORRECTIVE/PREVENtIVE/PREDECTIVEFIAINTEMNCE DIFFICULN Did a failure occur during o r a f t e r installation of project work o r equipment modification? Was there a corrective maintenance error during or after repairing or correcting an equipment malfunction? Was an error coamitted during or after performing scheduled preventive or predictive maintenance on equipment?

Refer t o Sections Of thraugh 08 f o r further developlent under

~ N S T A t C A T ~ ~ N / ~ R R C T I V / P R E V E N t T V E / P R E O I ~ H A I N T E ~ DIFFICULTY, NCE then return to C2.

c2. PREUECTlVE/PREVENTWE MAINTENANCE (PM) PROORAH Should a reasonable PH program have prevented the equipment na7functk~1 o r cqu5prsnt difficulty? Was the PH inadequate? Refer to Section 09, Pn WOT ADEQUATE, for further development under Pt4 program.

g g This category should only be used $f sound PM is not being i

i performed, or i s inadequate, for a pi- of equipment.

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09. fM INAOEQUATE Was an equfplsnt malfunction caused by inadequate or lack of PM?

Appendix C AP 0007 Rev. 1 Page I8 o f 21

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APPENDIX C (Continued)

I ,,' 3 I* 25. NO PH FOR EQUIPHCNT Was an equipment malfunction caused by nat having PM scheduled f o r equipment? Should there have been PM on the equipment that failed?

26. PM FOR EQUIPMENT INADEQUATE Was PH scheduled too infrequently, considering the vendor recornmen-dation, maintenance history, and industry experience for t h a t piece o f equipment? .. .. . .

EQUIPMENT RECIABILIP//bESIGN Was the e q u i p k n t difficulty or malfunction failure (reliability problem) o r caused by a Refer to Sections C3, C4, and C5 for further .. development under EQUIPMENT RELIABILITY/DESIGW.

C3. REPEAT FAILURE Was t h e equipment malfunction a repeat failure, known to have occurred in the past?

Refer to Section D l 0 for further development under REPEAT FAILURE.

D10. MANAGEMENT SYSTEH Did a known equipment reliabilfty problem exist f o r the equipment that failed such that management assignment of resources should have been reasonably expected to prevent recurrence?

E27. CORRECTIM ACTION

-- Should adequate and timely corrective action &en taken based on previously k m equipment malfunctions or reliability problems?

C4. UNEXPECTED FAILURE Was the f a i l u r e unpredictable, unforeseen, OF unexpected f o r the piece o f equipment? -.

,n

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Oid the efroc or difficuyty OCCUP during r design revieu p roccss? u Refer t o Sections 011 and Of2 f o r further development under DESIGN.

Append+% C AP 0007 Rev. 1 Page 19 o f 2 1

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APPENDIX C (Continued)

I .

NOTE 1 Code a71 human factor design problems under Section D3, HUMAN FACTORS.

I 011. DESIGN SPECIFICATIQNS Was an equipment malfunckion caused by inadequate design specifica-tions, not building equipment to design specifications, o r not antici-pating operational problems during design?

E28. SPECIFICATIONS .INAbQUATE Was an equipment aral'function caused by incorrect or inadequate design specifications or basic data? Were design standards or standards used f o r design, such as vendor or GE standards incorrect?

29. OESIGN NOT TO SPECIFfCATIONS Were t h e specifications f a r the design correct but t h e design did not m e e t the specifications? 1 Also consider dual coding under Section 012, OESIGN REVIEW, because t h e design review process can and should, i n many cases, detect designs that do not meet specifications.

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E 0 . PROBLEM NOT ANTICIPATE0 Dfd the designer not anticfpate and design equipment to withstand or adjust t o potential problems that might occur during equipment service

'lifetime?

A l s o consider dual coding under Section 012, OESIGN REVIW, because the design review process can and should, in @any cases, detect designs t h a t do not arrtCcipatc potential problem areas.

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Appendix C AP 0007 Rev. 1 Page 20 of 21 L

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1i 7  : APPENDIX C (Conti nued )

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A

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I @ OESIGN REVIW D i d the design review process f a i l to detect design errors?

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NOTE The cause of an equipment malfunction should only be coded as a design review error if the reviewer could have been reasonably expected to detect the error, reatiring that the reviewer i s usually not as familiar with a design as the designer.

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0 31. INDEPENDENT REVIEW XNAOEQUATE Was a design review error caused by failure to have adequate indepen-dent review by someone other than the designer?

83. CO#S~RUCTION/FABRI~TION Was the cause related to construction, fabrication, or vendor activities?

Refer t o Sections C6, C7, and C 8 f o r further deve7opment under COHSTRuCTIWN/FA8RICTXON.

C6. rNSfALLATIO~/nAINTENNCE OIFFlCULTY Did the difficulty or error occur during installation o f project work or equipment modifications or during maintenance on existing systems?

Refer t o Sections 01 through 08 for further development under INSTALlATIOW/~INtENANCE DIFFICULTY. Return to C7.

I C7. FABRICATION OXFFLCULTY AT W StfE Was an error mads during fabrication at the W site?

C8. FABRICATZUN OIFFICUftV - A t VENOOR SITE Was an error made during fabrication a t the vendor site?

I

! Appendix C AP 0607 Rev. 1

! Page 21 of 21

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.. . ... _. . .. SI OPERATING EXPERIENCE INFORMATION REVIEW INDEX NUMBER: CAR91063-01 RESPONSIBLE DEPARTMENT: PERFORMANCE ENGINEERING DUE DATE: 12/31/99 ( I ( I DATE INTTIATED: 09/19/96 RE: LEAK IN CONCRETE REACTOR PEDESTAL (MS-77).

CONTINUE TO INSPECT SAND DRAINS EVERY TEN YEARS.

(NEXT SCHEDULED SURVEILLANCE DUE 9-1-2001.)

SEE REC. 1.

- Item needs add'l closeout; DH to present to f o r final closeout.

(DH) Enter date presented: .... l"

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(OEC) Final closeout received: ' __ hp.TED SEP 2 8 BE 1999

.. I g.

M A P F 0028.01 AP 0028 Rev. 16 43

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MEMORANDUM SYSTEM ENGINEERING To: R.L. Rush Date: Septeniber 28. 1999 From: S.A. \-?ekasy

Subject:

Commitment Item CAR91063-0 1 DW Support Sand Drain Inspccrion The subject ER was willen to require continuing inspection of the drywell support sand cusluon and the sand drains on a tcn year interval. .An initial baseline inspection was perfonlied during 991. The next inspection is not scheduled until WI!O I . Due to the nature of the conimitlnenl tracking system, this inspeclion shows up on rhe current conimilment jlem list, even though there is no jntetitioti to perform this inspc'ction until 9: 1:O I.

To ensure that this inspection contiiiues to be properly tracked for completion on the correct due date, a new suiwillance has been established in accordance with AP 4000 (see attached VYADF 4000.0 1). Since the suiveillance system wili generate notification of the test before its due date, this conimirment item niay be closed. Tracking ofthe planned suiveillance through AP 4000 provides adequate assurance that this sunieillancc test will be done on schedule.

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. ' SURVEILLANCE' TESTXNG 'PRbG- CHANGE 'FORM "

I ' Initiating Department al/!~-k,Er\S\'!,,wr:h~, Date qr+Yl Test O w n e r Department &bEn;* k.'.

T y p e of change: New T e s t Deletion 0 Change 0 Complete all information as applik'able:

1.

.a 2.

3. Schedule Internal : f%r\  ;[G yem @

4. Base D a t e :  ?/I /oi . . -

1 I 5. Last Done Date : .G/4\ I 6.

i 7.

I 8.

I I

I 9.

10.

I I 11.

j 12.

13.

14. Plant Programs affected Sy this change: . bJ@-

I ( e g : ISI, IST, M a h t Rule, PM, Check Valve, and Relief Valve P r o g r a m s , etc) /

I 1 4 a . Plant P r o g r a m O y n e r Approval:

35

• I n i t i a t i n g Department Head

16. T e s t Owner Department Head Approval i 3.7. Change Received:

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Date: RV :

STC

18. Master Test L i s t By::

STC

99. Independent Veri :e : By :

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VYAPF 4000.01 (Sample)

AP 4000 Rev. 20 Page 1 of 1 RT No. 09.501.152

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OPERATING EXPERIENCE INFORMATION REVIEW DATE: 12/12/91

._

TO . . .

FROM  :

SUBJECT : CATEGORY-A COMMITMENT REVIEW Attached is a copy of commitment: cAR91063MEC1 This document is being assigned to you for assessment of its importance to safe plant operation and f o r specific action as indicated in the Additional Instructions below.

Please review the commitment, carry out additional instructions, and complete the lower portion of this form.

Type B Commitment RE: LEAK IN CONCRETE REACTOR PEDESTAL (MS-77).

PER REC.3, REVISE DRYWELL INSPECTION PROCEDURE TO REQUIRE INSPECTIONS OF TEE CONCRL'TE FLOOR INSIDE TEE DRYWBLL/CONTAINMl3NT WALL INTERSECTION.

SUBMIT THIS COMPLETED FORM AND OTHER RESULTS OF YOUR REVIEW TO THE OPERATING EXPERIENCE COORDINATOR (OEC) BY 03/01/92

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Additional Corrective Action Process per W Corrective Action Guideline Sig. CAR [-I Routine CAR 1-3 (DH) Enter date presented:

( O K ) Final closeout received:

. .. . . ..

HECBBNICAZl ENGINEERING AND CONSTRUCTION DEPARTmNT MEsORA?muEI TO: B. R. Buteau DATE: February 28, 1992 FROM: T.C. Trask fcT

SUBJECT:

Response To Category A Commitment Review cAIR91063MECl

1) Category A Commitment Review CAR91063MEC1, dated December 12, 1991.

2 ) Drawing 5920-233, Revision 0, l%owe.r Drywell Concrete Pours - Primary containment".

3) Category A C o d t m e n t Review SURV9011902CM1, dated December 7 , 1990.

4 ) OP 4115, Revision 2 7 , "Primary Containment Surveillance".

Background:

Category A Commitment Review CAR91063MECI requests t h e Mechanical Engineering & Construction Department to revise the w e l l inspection procedure to require inspections of the concrete floor inside the Drywell / Conkainment wall intersection.

This request stems from Recommendation No. 3 of the Containment Pedestal Leak Task Team Final Report, dated October 8, 1991. In summary, on September 24, 1991, a leak was noted f r o m the concrete pedestal under t h e Arywell. A f t e r a series of investigations, the Task Team concluded that the leak was caused by a packing leak on valve MS-77. The condensed steam from the leak had travelled a path between the steel containment shell and the concrete containment and sand cushion to eventually leak from existing cracks or cold joints in the pedestal. The Task Team also concluded that primary containment integrity was maintained throughout the event.

Although the source of the leak was identified to be external to the primary containment, t h e Task Team recommended that a visual inspection of the area at the intersection between the containment wall and the concrete floor inside the drywell be I

I I

. d

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. ..

I added to a drywell inspection procediure, A leak through t h i s intersection and the steel containment could result in an external leak similar to the one noted and be difficult to rapidly discover and identify, Discussion:

A review of plant drawings indicates that drawing 5920-233 provides the only available details of the subject intersection.

5920-233 indicates that the interface between the inside of the steel containment and the concrete floor is pressure grouted and filled w i t h a joint sealing compound at the edges. However, the exact surface condition of the compound, including paint coatings and cleanliness, and the ability to access the areas near t h e compound for visual inspections are both unknown at this time.

Such determinations are not possible until the upcoming refueling outage i

At present, two [2) procedures exist for inspections of the interior surfaces of the primary containment, OP 4115 and OP 5250. OP 4115, Section D and VYOPF 4115.04 require that the painted interior surfaces of the drywell be inspected for chips, abrasions, scale, blisters, and rust spots. Inspections of the total interior surfaces are also performed for cracked welds, loose anchor points, or structural deformation. It sfiould be noted that the inspections under OP 4115 are performed at the end of the refueling outage and serve as final confinnation of containment cleanliness and integrity prior to close out and plant startup. Until this t h e , these inspections have not shown the need for inspectionse2the s t a r t or early stages of the refueling outage.

OP 5250, Waintenance/Inspection of Primary Containment I n t e r i o r Surfaces,l@ was originally prepared in response to Category A Commitment Review SURV9011902cM1 and is presently undergoing final preparation by the Maintenance Department. This procedure provides for inspections of the painted surfaces within the -ell and torus and includes detailed instructions for surface preparation and painting, The inspections under this procedure are performed a t the early stages of the refueling outage, However, unlike OP 4115, they are specific to painted surf aces.

Conclusions :

At present, two concerns exist which preclude the addition of inspections of the joint sealing compound to a procedure.

First, the exact condition of and access to the cornpound mdke the preparation of detailed inspections instruction difficult.

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.Ad OPERATING EXPERIENCE INFORMATION REVIEW

! DATE: 12/12/91 I / e- -.

TO  : cAPPuccIp--j FROM  : BUTEAU ' 5. &&

YS

SUBJECT:

CATEGORY A COMMITMENT REVIEW

!

Attached is a copy of commitment: CAR91063MEC2

! This document is being assigned to you for assessment of its importance to safe plant operation and f o r specific action as indicated in the Additional Instructions below.

I Please review the commitment, carry out additional instructions, and I complete t h e lower portion of this form.

Additional Instructions: Type B Commitment C - - - ~ - - - - - - ~ - - L - - - - C I - - -

RE'. LEAK IN CONCRETE REACTOR PEDESTAL (MS-77).

PER REC.5, REVIEW W RESPONSE TO GENERIC LETTER 87-05 AND DETERXLNE I F REVISION I S NECESSARY.

S i g . CAR 1-3 Routine CAR [-I

-A copy of this complete document should be forwarded to training.

Department Supervisor Approval:

' Manager/Superintendent or Director Dispo I - commitment(s) and due date(s\,.

- Ifor t e m needs add'l closeout; final closeout.

DH to present to

( D H ) Enter date presented:

(OEC) Final. closeout received: --

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Second, neither of the existing inspection procedures provides an optimal location for these inspection instructions. Ideally, the inspections would be performed in t h e early stages of the outage to allow for sufficient t h e to effect repairs should they be required.

Recommendations:

Q Based on the above conclusions, a two step resolution is recommended. F i r s t , inspections of the joint sealing compound QnR this refueling outage w i l l be performed by MELC personnel under a qi036 Work Order. Upon acceptance of this recommendation, a Work Order Request will be initiated for this task. If 'any surface rAXz preparation or repairs are required, these tasks would also be controlled v i a Work Orders. .. .

Subsequent to the refueling outage, detailed inspection instructions will be prepared and included in an appropriate procedure. T h i s would be either a new section of OP 4115 to be performed at the s t a r t of the refueling outage, a new section of OP 5250 for items other than painted surfaces, or a new inspection procedure. T h i s decision will be based both on the content of the inspection instructions and discussions with Operations and Maintenance personnel.

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TUEE GROLTING METHOD I

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This letter was reviewed and determined that no revision is necessary as a result of the "pedestal leak" event.

Items 1) through 31 are unafFected by this event. The last i t e m (page 3 , "Response" needed to be considered. It states:

"Therefore, Vermont Yankee ... will conciude that no water has leaked into t h e sand gap area and if any water had it would have exited by way of the e i g h t drain lines provided."

Later the paragraph further states:

"However, if our investigations indicate the drain lines were not operating properly or undetected water has penetrated the gap area, Vermont Yankee will submit a revised response for your review."

The original concern is that water (from t'ne refuel c a v i t y ) has the potential to leak to t h i s lower elevation, undetected, such that the sand cushion would become wet, be in contact with t h e drywell shell, and promote unacceptable corrosion.

The f o l l o w i n g i s offered to address our letter statements and the o r i g i n a l concern of NRC (and t h e BwR's Owners Group position):

1) The event condition was such that VY had leakage that WAS detected.

2) The sand cushion w a s n o t wetted. Visual inspection verified it to be dry.

3 ) There is an existing gap between the drywell shell and the sand cushion as verified by inspection.

4) The drain lines were once again verified to be open and operable.

5 ) The drywell shell was visually inspected and verified to be dry and evaluated to have no corrosion concern.

It is concluded that:

1) No water has leaked in the sand cushion area.

2) If water had leaked into this area it would have exited v i a the drain lines.

3 ) Undetected water also did not enter into the gap area between the

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Based upon the above conclusions, the Vermont Yankee FVY 87-52 letter remains accurate and no revision is necessary.

Zn addition, the corrective actions taken are mezsures over and above our stated commitment. Most notable is the increased frequency of i n s p e c t i o n of the sand drain lines and the t o r u s floor areas.

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Outgoing NRC Correspondence VERMONT YANICEE LICENSING CORRESPONDENCE/COmITT4E8T CONTROL SEEET CATEGORY: STATUS: OPEN WOaC ORDER: 1-P DOCUMENT NUMBER(S): LAS 717 E7!Y 87-52 DOC- DATE: 5 f 8 187 RESPONS IBILITP: PLANT T 9 Jpp ..

FINALDUE: f I DRAFT DUE: / / LAST UPDATE: f / ,

DESCRIPTION: ~ ~ OF VY RE5-E ~ To A NRC -c L L m 87-05

-TlON - MARK I DRYWELL DEGFWATION.

REMARKS: LAIS 717 A, B AND C ASShED - SEE A5TA-m CLOSE OUT: LA1 710 CLOSED

- INTERNAL DISTRIBUTION .

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NSD Corporate , Brattleboro Additional J. E. Tribble J. G. Weignnd D. Y a s i (NSD)

A. C. KadaklL, E. Eeider D, A. Reid/W. P. Murphy J. Lance {NSD)

3. DeVincentis P, K. McElwee/D. D, Bauer E. Betti INSD)

D. McCue (1 copy) P. Donnelly ( P l a n t )

(Plant1 S. R. Miller N S 3 , P.

--2 Plant Pelletier J. K. Thayer R. J . Wanczpk R . W. Capstick R . D. Pagodin R. L, Smith/M, J. Marian 8 . #. Metell J. G. Robinson D. C. Girroir A. PI. Shepard - 2 Licensing File Copy (original)

Chrono Copy B. C . Slifer A. S. Christie

- . I EXTEWZDIST~IBUTIO-G~~

~Z Only I ,

Regulatory Affairs and Programs John Ritsher, Esq.

Boiton Edisoa Campany Ropes & Gray 25 Braintree Hill Office Park 225 Franklin Street Bfaintree, MA 02184 Boston, MA 02199 Richard C. DeYoung Charles M. Rice 15102. Interlachen Drive, No. 610 355 W, 14th Street Silver Springs, MD 20906 Idaho Falls, ID 83402 i

Robert G. Staker W. A. Zarbis, Fuel Licensing P.O. BOX 378 Nuclear Safety & Licensing Operation Germantown, MD 20874 General Electric Company 175 Curtner Avenue G. Tarrant, Chairman San Jose, CA 95125 Public Service Board 120 State Street NUS Carporat i o n Mnntnrl ie r . VT n56n7

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VERMOUT Y m E LICglPSXlC CORRESPOMIE#CE/CO~ITHEWT COH'MtOL SHEET CATEGORY: LIIl STATUS: OPEN WOEX OEtDI$R: -

DOCIRIENT BUMBEWS): r . a 71 7 A -

FVY 07 52 DOCWEIT DATE: 5 IR IR7 BESPOWSIBILITY: , *JPP P I W DUE: E!/ 7 f R 7 DRAFT DUE: / / LAST UPDATE: / I DRAINLINES PES 05 BELURKS :

50.54 f.

CLOSE OUT:

VERHOMT Y m E E LXCEUSIHG CQRRESPOWDE#CE/CO~fTnENTCOUTROL SHEEX CATEGORY: LAI STATUS: OPEN WORK ORDER: 1-P DOCUMENT W H B E R C S ) : LAX 717B Fvy 87-52 DOcUnlWT DATE: 5 1 8 1 87 RESPONSI3ILITY: PrJMT 9-FINAL DUE: / / DRAFT DUE: f i WS'I UPDATE: / I

-IN-ATION PER GENERIC LETTER 87-05 RESPONSE COMMITMENT.

REluRKS :

UNDER 50.54 f.

LOSE OUT:

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....

I AND B INVESTIGAFIW INDICATE DRAIN LINE INOPERABILITY OR UNDETECTED WATER PENETRATED THE GAP AREA.

CLOSE OUT:

I I CATEGORY:  ?.AI STATUS : . WORK ORDER:

DOCUMENT HUHBER IS 1 : DOCUnEIT DATE: / /

RESPONSIBILITY:

• m PIHAL DUE: / I DRAFT DUE: I / LAST UPDATE: I /

DESCRIPTIOI:

I I I L

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I VERMONT YANKEE I NUCLEAR POWER CORPORATION

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RD 5, Box 169,Ferry Road. Brattleboro, VT C5301 Warren P Murphy Vice Presldent and i Manager of Operations (8021 257-5271 May 8 , 1987 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Office of Nuclear Reactor Regulation Mr. Thomas E. Murley

References:

a) License No. DPR-28 (Oocket No. 50-271) b) tetter, USNRC to All Licensees o f Operating Reactor (BWR'sf bvuith Mark f Drywefls (Generic Letter 8 7 - 0 5 ] ,

dated 3/12/87 c) IE Information Notice 86-99: Degradation o f Steel Containments, dated 12/8/86 Oear Sir:

Subject : Response to Generic Letter 87-05 . Request f o r Additional

-

Information Assessment o f Licensee Measures to M i t i g a t e and/oP Identify Potential D@gradation of Mark I Drywells By Generic Letter 87-05 [Reference b ) ] and pursuant to 10CFR50a54(f), you requested t h a t each licensee o f an operating reactor with Mark I drywell submit a formal response of i t s review. This letter provides Vermont Yankee Nuclear Power Corporation's response to that request.

Specifically, you requested, under oath or affirmation, responses to t h e following:

Item I) Provide a discussion of your current program and any future plans for determining i f the drain lines that were provided at your facility f o r removing any leakage that may result from refueling or from spil'lage o f water i n t o t h e gap between the drywell and the surrounding concrete or from the sand cushion itself are unplugged and functioning as designed.

Resoonse Information Notice 86-99 [Reference c ) ] identified a potential problem with drywell corrosion at Oyster Creek, Vermont Yankee began an immediate review of the conditions and their applicabilty t o Vermont Yankee's containment. A walk-down was performed by the Operations Oepartment which verified the installation

VERMONT YANKEE NUCLEAR POWER CORPORATION U.S. Nuclear R e g u l a t o r y Commission May 8 , 1987

-Page 2 o f t h e d r a i n l i n e s ( a t o t a l o f e i g h t 1" PVC d r a i n l i n e s ) which lead from t h e sand r e g i o n between t h e d r y w e l l s h e l l and t h e concrete. A v i s u a l i n s p e c t i o n was a l s o performed w h i c h i n d i c a t e d no leakage from any o f t h e e i g h t d r a i n l i n e s .

Vermont Yankee w i l l complete an i n t e r n a l i n s p e c t i o n o f the drain fines by I\ L ,.\

l e a k , w i l l p r o v i d e Vermont Yankee adequate assurance t h a t any p o t e n t i a l water leakage i n t o t h e sand r e g i o n would n o t go u n d e t e c t e d I terii 2 ) Pi-o\/icie a d i s c u s s i o n of p r e v e n t i v e maintenance and i n s p e c t i o n a c t i v i -

t i e s t h a t a r e c u r r e n t l y performed o r are planned t o m i n i m i z e t h e p o s s i b l i t y o f leakage from t h e r e f u e l i n g c a v i t y p a s t t h e v a r i o u s Seals and g a s k e t s t h a t m i g h t be p r e s e n t .

The e x i s t i n g r e f u e l i n g c a v i t y design a t Vermont Yankee i n c l u d e s f u l l y welded s t a i n l e s s s t e e l / c a r b o n s t e e l c o n s t r u c t i o n w i t h a backup b a r r i e r channel and seal r u p t u r e d r a i n . In a d d i t i o n , an a l a r m system i s p r o v i d e d t o d e t e c t any b e l l o w s o r d r a i n l i n e leakage, F i g u r e 1 S e c t i o n A-H o f t h e Oyster Creek d r y w e l l t o c a v i t y s e a l ( o f Generjc L e t t e r 8 7 - 0 5 ) i n d i c a t e s t h a t t h e source o f l e a k i n g was a gasket a t t h e c a v i t y drain. The 4 2 ' d i a m e t e r d r y w e l l t o r e a c t o r b e l l o w s a t Vermont Yaniee i s sealed w i t h a p e n e t r a t i o n weld n o t a g a s k e t . I n a d d i t i o n , as a b a c k u p i n t h e e v e n t O f leakage i n the b e l l o w s o r d r a i n p i p i n g , an a d d i t i o n a l s t a i n l e s s steel water b a r r i e r i s i n c l u d e d as part o f t h e c o n c r e t e 1.iner t o c a t c h any w a t e r . A 3" diame-ter bellows r u p t u r e d r a i n welded t o t h e Water b a r r i e r p r o v i d e s a f l o w p a t h f o r a n y leakage t o t h e equipment d r a i n 1qi-I-h an alarm system t o n o - t i f y o p e r a t o r s i n t h e event of bellows leakaae.

Item 3 ) Con.Firm t h e i n f o r m a t i o n l i s t e d i n Table 1 i s c o r r e c t w i t h r e g a r d t o your f a c i l i t y .

The i n f o r m a t i o n t h a t :.!as o r i g i n a l l y p r o v i d e d i n T a b l e I was p r e l i m l n a r y i n f o r m a t i o n o n l y . A more d e t a i l e d revie?! has been comple-ted k ! i t h the f01 lowing I'PSLI 1 t s ,

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VERMONT YANKEE NUCLEAR POWER CORPORATION I

U.S. Nuclear Regulatory Commission May a, 1987

-!3+3-Sand Gap Details Drawing Available - Yes G191481, Rev. 2 Wall Thickness UT Performed - NO UT Method/Results Sent to NRC c No Gap Material - E thafoam Was Gap Material Removed c Yes - See Note 1 NOTE I: In order to create the 2 " gap, a layer o f Ethafoam material was attached to the steel prior to the concrete pour. Tu form this 2" gap at Vermont Yankee, 2" thick sheets of Ethafoam were placed between the steel liner and a ,040 sheet of Noblock plastic sheeting whicn kept the concrete from adhering to the Ethafoam.

Concrete was then poured against this in 3' l i f t s and allowed to set. The Ethafoam sheets were then removed creating the 2" gap.

Upon removal o f the Ethafoam, 2" t h i c k by 6" wide strips o f polyurethane were placed circumferentially in the t o p of the opening t o prevent objects from entering the gap. This process was repeated for the several concrete lifts necessary to form the shield wall .

Itern U t 4----I Owners Whose Designs Are Such That the Sand C,ushion 3 Ooen To Between The Orywell Shell and Surroundinq Concrete Provide any plans for performing ultrasonic thickness measurements of t h e drywell shell plates adjacent to the sand cushion or any other proposed actions to ascertain if plate degradation has occurred.

Since the degradation that has occurred at Oyster Creek is localized, sufficient details should be included to show that the sampling basis for ultrasonic thickness measurements i s adequate in terms o f s i z e and test location.

Response

As identified in Reference b ) , Oyster Creek identified localized degrada-tion as a result of some water leakage i n t o the sand region surrounding t h e con-tainment shell. This leakage was attributed to the deterioration of a drain line gasket at the drywell t o cavity bellows. Further, ciue to Vermont Yankee's design f o r the refuel bellows, we do not believe any water nas or will leak into the 2" gap area undetected. Therefore, Vermont Yankee, assuming satisfactory results of its visual inspection of the drain lines, will conclude that no water has leaked i n t o the sand sap area and if any water had it would have exited by way of the eight drain lines provided. Based on the above discussion, combined with potentially significant ALARA concerns, Vermont: Yankee feels ultrasonic testing of the drywell shell is not warranted. However, i f our investigations indicate the drain lines were not operating properly or .undetected water has penetrated the gap area, Vermont Yankee wi77 submit a revised response for your review.

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I I VERMONT YANKEE NUCLEAR POWER CORPORATiON 1  : U.S, Nuclear Regulatory Commission May 8 , 1987

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We trust that the above information adequately addresses your request; however, should you have questions or desire additional information, please do not hesitate to contact us.

Very t r u l y yours, VERMONT YANKEE NUCLEAR POWER CORPORATION Warren P. Murphy Vice President and Manager o f Operations STATE OF VERMONT) 1ss WINDHAM COUNTY )

Then personally appeared before me, Warren P. Murphy, who, being duly sworn, did s t a t e t h a t he is Vice President and Manager of Operations of Vermont Yankee Nuclear Power Corporation, t h a t he i s duly authorized to execute and f i l e the foregoing document i n the name and on the b e h a l f o f Vermont Yankee Nuclear Power Corporation and that the statements therein are true t o t h e best o f h i s knowledge and belief.

Diane M. McCue Notary P u b 1 i c My Commission Expires February 10, 1991

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I OPERATING EXPERIENCE INFORMATION REVIEW 1 I DATE: 12/12/91

.. TO Attached is a copy of commitment: CAR91063MEC3 Additional Instructions: Type B Commitment:

........................

RE: LEAX IN CONCRETE REACTOR PEDESTAL (MS-7?)*

PER W C . 6 , REVIEW BWROG LETTER TO NRC DATED 12-22-89 AND DETERMINE IF FURTHER ACTIONS ARE APPROPRIATE.

S i g . CAR [,I Routine CAR I-]

(DH) Enter date presented:

(OEC) Final closeout received:

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BUJR OUINRS' GROUP -

yettdle Street flaleigh, NC 27602 BWROG-8997 December 22, 1989 RECEIVED M r . 6 . Bagchi, Chief Structural and Geosciences Branch OPS. SUPPORT Division o f Engineering Technology U. S. Nuclear Regul atory Commi ssi on Washington, DC 20555 c

Subject:

BWROG RECOMMENDATIONS ON DRYWELL INSPECTIONS

Reference:

James E. Richardson (NRC) to Don Grace (BWROG), "Inservice Inspection o f Mark I Drywell Steel Shells," June 23, 1989

Dear Mr. Bagchi:

In response to the reference letter, Attachment 1 provides BWR Owners' Group (BWROG) recommendations regarding inspection o f the drywell sand cushion region. These recommendations apply only to the plants a t issue; that is, certain Mark I and Mark I1 plants but not Mark 111 plants. The BWROG believes that t h e program described in the attachment w i l l assure that the BWR facilities at issue will continue to operate in a safe manner w i t h o u t undue risk to public health and safety, by the prevention and/or rapid detection o f drywell shell corrosion.

The approach recommended by the BlJROG i s to determine first whether a potential corrosion concern exists. This aim i s accomplished by assuring that the drain system dedicated to the drywelllbioshield gap is functioning so that any leakage into the gap is not only quickly eliminated but also readily detected. When warranted, thickness measurements are taken to determine the extent o f any corrosion if it e x i s t s .

Attachment 2 provides recommendations on a process and schedule for determining inspection requirements for the wetwell and the remainder of the drywell.

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-. BtJROG -8997 December 22, 1989 Page 2 The commeots/positions provided i n this letter have been endorsed by a substantial number o f the members of the BWROG; however, it should.not be interpreted as a commitment o f any individual member to a specific course o f action. Each member must formally endorse t h e BWRUG position in order f o r t h a t position to become that members position.

Sincerely yours, Stephen D. Floyd, Chairmao BWR Owners Group cc: F. 3 . Miraglia, NRC G. 3 . Beck, BWROG Vice Chairman D. N. Grace, RRG Chairman BWROG Primary Representatives BWROG Executive Oversight Committee BGIROG Drywelt Inspection Committee W. A. Zarbis, GE

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I ATTACHMENT I BWROG Recommendations for Inspections of Drywefl Sand Cushion Region I

1. INTRODUCTION In November 1986, thinning of the drywell wall was observed at a BWR/2 with a Mark I containment. The thinning is attributed to corrosion induced by the presence o f moisture in the sand cushion. The source o f the moisture was leakage from the refueling pool through fatigue cracks in the cavity seal and possibly the bellows at the drywell-to-cavity seal.

A t all Mark I plants except BrunswSck Units 1 and 2 and at a single Mark I1 plant (WNP-Z), a gap exists between the steel drywe77 and the surrounding concrete bioshield structure. All of these plants except Hope Creek are equipped with a sand cushion at t h e bottom of the drywell/bioshield cavity.

Tu prevent collection o f water $n this region, ft is equipped with drain lines that typically open onto the torus room floor. In some plants, the sand cushion is sealed from the cavity by a steel plate; in these plants t h e sand cushion may n o t have drain lines. However, tbe region above the steel p l a t e is equipped with drain lines.

By letter dated June 23, 1989, the NRC proposed recommendations regarding inspection o f the drywell shell f o r those plants with a drywell/bioshield gap. Representatives o f the BWR Owners' Group (BWROG) met with the NRC on October 4, 1989, to discuss these proposed inspections. As a result o f that meeting, the BWROG agreed to investigate the measures needed to preclude or detect potential corrosion of the drywell at or around t h e sand cushion region.

'Provided below are the BWROG recommendations and supporting discussion.

2. BWROG RECOWENDATTONS In general, the BWROG approach emphasizes first, measures t o be taken to detect and mitigate potential leakage, and second, additional inspections to minimize the potential for leakage into the gap region. The advantage o f t h i s approach is that utilities can readily determine whether conditions necessary for corrosion are present, prior to undertaking costly and difficult actions such as ultrasonic testing (UT) required to detect corrosion.

A . Verify the functionality o f drain l i n e s i n and above the sand cushion.

The primary means o f detecting leakage is to monitor the drain lines in or above the sand cushion. The drain system i s designed t o collect and remove moisture from the sand cushion or, for those plants w i t h a sealed sand cushion, from the air gap above the sand cushion. If the drain lines are functional, any leakage into the drywell/bioshield gap can be readily observed at the drain line outlet.

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I A t the beginning o f its next refueling outage, each plant should verify functionality o f the drain system v i a an initial inspection using a boroscope, compressed air, smoke kits, or other appropriate means. If thjs initial inspection indicates that the drain lines are functfoggl., then additional inspections of the drains should be conducted a t a frequency deemed appropriate by the individual uti1 fty, but at feast once every ten years. The ten-year in$eclion frequency is justified because there is no likely mechanism which would cause the drains to become nonfunctional, especially those in the sand cushion, where the sand acts as a filter to prevent matter from reaching and thus plugging the drains. In addition, there are a number of drain lines, providing sufficient redundancy to ensure t h e drain system will function.

If the drain lines are nonfunctional, then corrective action should be taken. The Tines should then be inspected again at the beginning of the next refueling outage, and i f they remain functional, subsequent inspections should be conducted as discussed above.

B. kook for sierns of leakaoe.

Upon confirmation that a free flow path exists between any potential leakage sources and the drain system, plants should conduct inspections to look for signs o f leakage. These inspections should be conducted early during each refuel ing outage, after the refueling pool has been filled, and repeated at the end o f the refueling outage.

Plants should also Took for signs o f leakage from previous outages, such as stains near the outlets o f the drain system.

It is also suggested that plants without a sealed sand cushion insert i n t o the sand cushion through the drain lines an instrument suitable for indicating the presence of moisture i n the sand cushion, such as those commercially a v a i l a b l e for measuring moisture in soil. An alternative would be to insert a carbon-steel specimen into the sand cushion and periodically withdraw it to look for signs o f corrosion.

C. Perform thickness measurements if there i s evidence of leakaae, Thickness measurements o f the drywell are costly and difficult, particularly measurements o f the region adjacent to the sand cushion since this area i s surrounded by concrete. In the sand cushion region, concrete would have to be chipped or drilled to permit the measurements. The difficulty o f this task would also limit the amount o f surface area measured to a small percentage of the total surface area. Since any corrosion would likely be randomly located, the probability of detecting it would consequently be low. Because of the difficulty of performing them, and becahe of their questionable worth, thickness measurements should be performed only if corrosion is suspected, based on the presence o f water as discussed in the preceding paragraphs.

Plants were typically built with margin to the drywell shell thickness required by industry standards. Recent measurements at a BWR/3 as part of the Plant L i f e Extension Program demonstrated shell

thicknesses in excess o f design requirements. In a briefing of the Commission on October 25, 1989, T. E. Murley (Director, NRR) stated that corrosion o f containments has affected only the margin above code limits on thickness, and that as long as the containment meets the code, there is still two to three times as much thickness as needed.

I f corrosion is not suspected, more than adequate wall thickness remains to ensure cont ai nnient integrity .

If evidence o f pro1 onged leakage exists, then thickness measurements should be made at the next outage o f opportunity after the evidence is observed. If the leakage i s observed to have come from the sand cushion region, the measurements should be made at that elevation.

For plants with a sealed sand cushion, i f leakage i s observed from the region above the sand cushion, thickness measurements should be made at that eleva$ion; however, measurements need not be made at the sand cushion unless leakage i s also observed at t h a t location.

Thickness measurements should be repeated at the same locations two refueling outages or approximately three years after the first ones are made. From these two sets of measurements the corrosion rate can be establ ished. The frequency o f subsequent measurements should then be based on the corrosion rate and may be less frequent then every three years.

It may be justifiable to not perform thickness measurements if the leakage was a one-time occurrence or of a small amount (for guidance, an amount comparable to the volume o f the drain line would be considered a small amount), and the source o f the leakage was detected early o r has been eliminated. A small amount o f leakage would not induce a significant amount o f corrosion. Measurement of the moisture content o f the sand cushion and the relative humidity o f the air in the drywell/bioshield gap would indicate whether conditions are present to cause extensive corrosion and thus whether thickness measurements are required.

D.

1 eaks.

As discussed above, the primary means o f detecting leakage is by monitoring the drain lines i n and above the sand cushion. However, i t i s advisable although not necessary to minimize the potential for leakage i n t o the drywell/bioshield gap by inspecting for leaks in the refueling cavity. Each plant should determine the necessity for and the degree of inspections o f the refueling cavity or other sources of potential leakage into the drywell gap.

There are numerous joints and seals associated with the refueling cavity. Only those joints and seals which would allow water into the drywell/bioshield gap if they leaked may need to be inspected. Also, only those joints that rely on sealing compounds or gaskets may need periodic inspection. Seal welded j o i n t s and the drywell bellows should be good for the 'life o f the plant. In addition, the drywell bellows is protected by a large guard plate that is not easily

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removed; removal o f this plate would increase outage time and personnel radiation exposure.

I t i s suggested t h a t plants perform an i n i t i a l inspection o f only the j o i n t s and seals potentially susceptible t o leakage, and repeat the inspection a t an approprlate interval b u t a least once every ten years.

3. EXCEPTIONS Individual p l a n t s may justifiably take exception t o some or a l l o f the inspections discussed above, depending on whether they had previously performed an inspection i n response t o Generic Letter 87-05. In addition, p l a n t s may take credit for mitigating design features or analyses such as those l i s t e d below'to reduce or eliminate some inspections:

E x t e r i o r surface o f the drywell coated with a superior grade of corrosion resistant primer; or Thickness of drywell wall increased by design t o specifically allow for corrosion; o r Lack o f a sand cushion; or Demonstration by analysis t h a t the corrosion r a t e will n o t a f f e c t t h e 1i f e o f the drywell.

ATTACHMENT 2 BWROG Recommendat ions for Inspections o f Drywell and Wetwell provides BWROG recommendations regarding inspections,of the sand cushion region of the drywell. As a result o f the October 4, 1989, meeting with the NRC, the 3WROG also agreed to recommend an approach for determining inspection requirements f o r the wetwell and the remainder o f the drywell.

The ASME Boiler and Pressure Code,Section X I , Division 1, Subsection IWE, "Requirements for Class MC and Metallic Liners o f Class CC Components of Light-Water Cooled' Power Plants", provides guidance for conducting inspections of BWR containments. This document i s a l i v i n g document that can be revised as needed to address new inspection requirements t h a t may arise. IR fact, Subsection IWE i s currently being amended to require examination of areas 1 ikely to experience accelerated aging and degradation. Other substantial revisions are a1 so underway, including one to require ultrasonic thickness measurements o f areas of potential containment degradation.

The BWROG proposes to follow the work o f the ASME as they revise and finalize Subsection IWE, and will make recommendations as needed regarding drywell and wetwe'll inspections. Since the NRC i s also involved w i t h the development o f Subsection IWE, the ASME process provides a common forum for arriving at a mutually acceptable inspection program.

The BWROG committee charged with resolving this issue will meet early in 1990 to develop a recommended long term course o f action for consideration by the BWROG.

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OPERATING EXPERIENCE INFORMATION REVIEW DATE: 03/03/92 I Attached is a copy of commitment: CAR91063MEC4 This document is being assigned to you f o r assessment of its importance to safe plant operation and f o r specific a c t i o n as indicated in the Additional Instructions below.

Please review the commitment, carry out additional instructions, and complete the lower p o r t i o n of this form.

I Additional Instructions: Type B Commitment

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Sig. CAR [-I Routine CAR] , [

- &tern is complete, well documented: no f u r t h e r tracking required.

- Item needs addl closeout; DH t o p r e s e n t t o for final closeout.

(DH) E n t e r d a t e presented:

(OEC) Final closeout received:

A

+

MECHANICAL ENGINEERING AND CONSTRUCTION DEPARTMENT MEMORANDUM TO: B.R. Buteau DATE: March 15, 1992 FROM: T.C. TraskfCf

SUBJECT:

Supplemental Response To Category A Commitment Review CAR9 1063MEC1.

References:

1) Memo, TC Trask to BR Buteau, "Response to Category A Commitment Review CAR91063MEC1," dated February 28, 1992.

2) Drawing 5920-233, Revision 0, '!Lover Drywell Concrete Pours - Primary Containment1'.

3) Memo, TC Trask to BR Buteau, Response to Category A Commitment Review SURV90119Q2CM1,1*dated January 2, 1992.

Background:

Category A Commitment Review CAR91063MECl requested the Mechanical Engineering & Construction Department to revise the drywell inspection procedure to require inspections of the intersection of the concrete f l o o r and the inside Drywell wall.

This request stemmed from Recommendation No. 3 of the Containment Pedestal Leak Task Team Final Report, dated October 8, 1991. The Task Team recommended that a visual inspection of the area at the intersection between the containment wall and the concrete floor inside the drywell be added to a drywell inspection procedure. A leak through this intersection and the steel containment could result in an external leak similar to the one noted in September, 1991 and be difficult to rapidly discover and identify.

Reference 1) recommended a two step resolution, w i t h the first step being inspections of the wall/floor intersection t h i s refueling outage by ME&C personnel. This recommendation was the result of unknowns regarding t h e exact surface condition of the intersection, including paint coatings and cleanliness, and the ability to access the areas near the intersection f o r visual inspections.

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This memorandum provides the results of the inspection performed by Mark Stello and myself on this date. Conclusions and Recommendations resulting from this inspection are a l s o included.

Discussion:

The results of the inspection performed are as follows:

1) The area of the intersection was easily accessed for the entire circumference of the drywell, Representative areas were video taped for later reference.

2) Contrary to Drawing 5920-233, no joint sealing compound was identified at the intersection, Drawing 5920-233 indicates

!

that a joint sealing compound was to be applied at the intersection.

3) The actual configuration found was a 45 degree bevel at the concrete edge, approximately 1 inch in both depth and width.

A sketch is attached as Figure 1.

4) The bevel was filled with dirt and some standing w a t e r . The dirt was easily cleared away to allow inspection of the sides and bottom of the bevel.

5) The bottom of the bevel was viewed to be tight against the drywell liner. T h i s would support the D r a w i n g 5920-233 statement that the interface between the inside of the steel containment and the concrete f l o o r was pressure grouted.

6) No evidence of corrosion of the steel drywell liner was noted. Areas where the paint was no longer intact were noted, but the primer coat was still intact.

Conclusions:

It is engineering judgement that the existing bevel may have been considered too small for proper installation and retention

!

of the joint sealing compound.

While the existing bevel configuration is not optimal, as it provides a location for the accumulation of standing water and dirt falling down tBe drywell wall, it is not considered an immediate concern and there is adequate assurance that primary containment integrity will be maintained for the following operating cycle. This conclusion is based on the following:

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I) Required Leakage Path:

A s discussed in Reference 1) and the Containment Pedestal Leak Task Team Final Report, leakage must occur through both the intersection and the steel containment liner.

2) Physical Condition of the Existing Bevel:

As noted in observation #5, the concrete appears to be tight against the steel liner.

3) Physical Condition of the Steel Containment Liner:

a) As noted in observation #6, no corrosion of the interior of the steel containment liner was observed.

b) As also noted in observation #6, the primer coat was observed to be intact. Reference 3) notes that the existing primer in both the Drywell and the Torus is well cured and exhibits excellent adhesion and durability. The primer provides adequate protection for the primary containment interior surfaces, and no re-application of topcoat is required.

c) A s a l s o discussed in the Containment Pedestal Leak Task Team Final Report, no evidence of leakage through the steel containment liner has been observed. Samples of the sand fill under the liner were dry.

4) Performance of the Type A ILRT:

Performance of the T y p e A ILRT verifies that the total primary containment leakage rate at 44 psig is less than 7 5 %

of the maximum leakage rate assumed to occur following a design basis accident. Should leakage occur through both the intersection and the steel containment liner, such leakage would be seen during the ILRT and analyzed accordingly.

5) Inerted Primary Containment Atmosphere:

Should corrosion be present at this time, further acceleration of the corrosion is not considered probable because the primary containment is inerted during power '

operation.

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Recommendations:

Based on the above conclusions, it is recommended that no further actions be taken during the present refueling outage.

During the next operating cycle, it is recommended that:

1) An investigation be performed to determine if the present generation of joint compounds or sealants can be properly

! installed in the existing bevel with adequate assurance that failure will not result.

2) Irrespective of the results of Recommendation #1, plans should be made to clean, prepare and paint both the bevel and the surrounding area during the n e x t refueling outage,

3) Following the completion of Recommendations 81 and # Z ,

detailed inspection instructions be prepared and included in an appropriate procedure. This would be either a n e w section of OP 4115 to be performed at t h e start of the refueling outage, a new section of OP 5250 for items other than painted surfaces, or a new inspection procedure. This decision will be based both on the content of the inspection instructions and discussions with Operations and Maintenance personnel.

.sc Approved : a rvisor 1 ' Date 4

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EXPERIENCE INFORMATION REVIEW DATE: 04/04/92

e.. . .

1 TO  : CAPPU I FROM  : BUTEA

SUBJECT:

CATEG Attached is a copy I of commitment: CAR91063MEC5 I

This document islbeing assigned to you for assessment of its importance to safe p l a n t operation and f o r specific action as indicated in the Additional Instructions below.

!

Please review the commitment, c a r r y o u t additional instructions, and complete the lower portion of this farm.

Type B Commitment RE: LEAK IN CONCRETE REACTOR PEDESTAL (MS-77).

ADDRESS RECOMMENDATIONS IN RESPONSE TO "CAR91063MT4." RESPOND TO REC-1-3 RE: JOINT COMPOUNDS, PREPARATIONS,INSPECTIONS.  !

I

!

I I

- Item is complete, well documented; no f u r t h e r tracking required.

L A d d i t i o n a l commitment tracking; required; initiate the following commitment(s) and due date(s).

I.

- Item needs add'l closeout; DH to present to for final closeout.

(DH) Enter date presented: djAs (OEC) Final closeout received:

$A

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MECHANICAL ENGINEERING AND CONSTRUCTION DEPARTMENT MBMORAETDDM TO: B.R. Buteau DATE: January 25, 1993 FROM: T.C. Trask fcT

SUBJECT:

Response To Category A Commitment Review cAR91063MEC5

References:

Memo, TC Trask to BR Buteau, ltSupplementalResponse to Category A Commitment Review CAR91063MEClt1, dated March 15, 1992.

Memo, TC Trask to BR Buteau, "Response to Category A Commitment Review CAR91063MECla1, dated February 28, 1992.

Drawing 5920-233, Revision 0, "Lower Drywell Concrete Pours

- Primary Containment".

Memo, TC Trask to BR Buteau, taResponseto Category A Commitment Review SURV9011902CM1~f,dated January 2, 1992.

OP 5250, Revision 0, l@Maintenance / Inspection of Primary Containment Interior Surfaces".

Federal Register Notice 57FR54860, "Proposed Generic Letter on Augmented Inservice Inspection Requirements f o r Mark I and Mark I1 S t e e l Containments, Refueling Cavities and Associated Drainage Systems", dated November 20, 1992.

Background:

Category A Commitment Review CAR91063MEC5 requested the Mechanical Engineering t Construction Department to respond to recommendations 1 through 3 in Reference l), regarding the use of joint compounds and painting and inspection of t h e intersection of the concrete floor and the inside Drywell wall.

The recommendations stemmed from inspections made by ME&C personnel during the 1992 Refueling Outage. Those inspections noted that no joint sealing compound was present at the intersection, contrary to Drawing 5920-233,. dkf 6 A/, 2.

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I The inspections, in turn, stemmed from the ME&C review of Category A Commitment Review CAR91063MECl and Recommendation No.

3 of the Containment Pedestal Leak Task Team Final Report, dated October 8, 2991. The Task Team recommended that a visual inspection of the area at the intersection between the containment wall and the concrete f l o o r inside the drywell be added to a drywell inspection procedure. A leak through this intersection and the steel containment could result in an external l e a k similar to the one noted in September, 1991 and be difficult to rapidly discover and identify.

This memorandum provides responses to the recommendations, based on studies performed during 1992.

Discuss ion:

Recommendation 1 :

I! '

An investigation be performed to determine if t h e present generation of joint compounds or sealants can be properly installed in the existing bevel with adequate assurance that failure will n o t result.

Response :

Discussions with representatives from Dow corning and 3M have indicated that joint compounds are not presently available that provide adequate assurance that failure would

!

not result over the remaining life of the plant. T h i s decision is based on three points:

a) The existing configuration found at the concrete edge, i.e., a 45 degree bevel approximately 1 inch in both depth and width, will not allow or the joint compound to be Locked in place, b) The differential thermal expansion between the steel drywell and t h e concrete f l o o r would result in expansion and contraction of t h e compound, increasing the likelihood of failure, and c] The present generation of joint compounds has not been qualified to remain intact and functional in post-LOCA radiation, humidity, and temperature conditions, 2

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I Recommendation 2:

Irrespective of the results of Recommendation #l, plans should be made to clean, prepare and paint both the bevel and the surrounding area during the next refueling outage.

ResDonse:

During the 1993 Vermont Yankee budget preparation process, the responsibility and budget for performance of the primary containment coating inspection and maintenance was transferred f r o m the Maintenance Department to ME&C. A review of the present budget and workscope indicates that sufficient funds exist to clean, prepare and paint both the bevel and the surrounding area during the 1993 Refueling Outage, in addition to the normally expected workscope.

Recommendation 3:

Following the completion of Recommendations #1 and #2, detailed inspection instructions be prepared and included in an appropriate procedure. This would be either a new section of OP 4115 to be performed a t the start of the refueling outage, a new section of OP 5250 for items other than painted surfaces, or a new inspection procedure. This decision will be based both on the content of t h e inspection instructions and discussions w i t h Operations and Maintenance personnel.

Response

Based on the response to Recommendation #2, i.e., both t h e bevel and the surrounding area be painted, the appropriate location for inspection and maintenance of the area is OP 5250. A marked up copy of t h e applicable pages of OP 5250 is attached to this memorandum.

conclusions:

It is concluded that both the bevel and the surrounding area be painted during t h e 1993 Refuelinq Outage and then inspected and maintained in accordance with OP 5250.

While t h e existing bevel configuration is not optimal, as it provides a location for the accumulation of standing water and d i r t falling down the drywell wall, the conclusions provided in Reference 1) are still considered valid and there is adequate assurance that primary containment integrity will be maintained.

3

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It should also be noted that this issue may be r e v i s i t e d based on t h e studies required to answer the Generic L e t t e r proposed in Reference 6 ) , a copy of which is a t t a c h e d .

- 1 Vol. 57, No. 225 1 Friday, Novenber 20.1992

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(5 . .

.552m F e d e d Regis'kr Notices I

Federal RGsIer 1 Vd. 57. No. 225 / Friday, November 20, 1992 / Notices 54861

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4 c:

a.

c Dept. Supv. Proc. No. _ O P 5250 PORC 92-17 Rev. No. oricrinal QSS Issue Date - / 9 2 Plant Mgr. Review Date-Sr. VP, Ops.

MAINTENANCE I INSPECTION OF PRI MENT INTERIOR SURFACES 1.0 PURPOSE 1.1 To provide information and instructions necessary for the Maintenance Department personnef to perform inspections and maintenance on primary containment interior surfaces.

1.2 Performance of Section 6.1 of this procedure implements Technical Specification 4.7.A.1.

2.0 DfSCUSS1ON 2.1 Protective coatings have been applied t o the interior surfaces of both the drywell and torus both t o inhibit corrosion and to aid in decontamination. The protective coating originally consisted of an epoxy topcoat applied over an inorganic zinc primer.

2.2 Inspections performed during previous refueling and maintenance outages have observed peeling of the epoxy topcoat. However, the existing primer in both the Drywell and the Torus is well cured and exhibits excellent adhesion and durability. The primer provides adequate protection for the primary containment interior surfaces, and no re-application of topcoat is required.

2.3 The protective coatings applied to the interior surfaces of both the drywell and torus are defined as Class 1 Service Level in accordance with ANSI N101.4-1972. Class 1 Service Level applies to those systems and components of nuclear facilities which are essential (11 to prevent postulated accidents which could afYect the public health and safety or (21 to mitigate the consequences of these accidents.

2-4 QC shall be applied to this procedure as necessary to ensure job quality. In addition, pretesting of the paint application personnel may be specified.

2.5 ATTACHMENTS 2.5.1 WOPF 5250.01 Drywell Inspection Record 2.5.2 WOPF 5250.02 Torus Inspection Record 2.5.3 W O P F 5250.03 Protech've Coating Application Record OP 5250 Original Page I of 12 a2

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9

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3.0 REFERENCES

3.1 Technical Specifications 3.1 .I Technical Specifications Section 4.7.A.1 3.2 Administrative Limits 3.2.1 AP 0125,Plant Equipment Controf 3.3 Other 3.3.1 -

ANSI N45.2.S 1978 Qualifications of Inspection, Examination, and 'Testing Personnel for Nuclear Power Plants 3.3.2 -

ANSI N5.12 1974 Protective Coatings (Paints) for the Nuclear lndustry 3.3.3 ANSI hi101.2 - 1972 Protective Coatings (Paints) for Light Water Nuclear Reactor Containment Facilities I

3.3.4 -

ANSI N101.4 1972 Quality Assurance for Protective Coatings Applied t o Nuclear Facilities 3.3.5 Steel Structures Painting Council, Steel Structures Painting Manual, Volumes 1 and 2, Third Edition, June 1983 3.3.6 ASTM D 4228-83 Standard Practice for Qualification of Journeyman Painters for Application of Coatings t o Steel Surfaces of Safety-Related Areas in Nuclear Facilities 3.3.7 YOQAP-1 A Operational Quality Assurance Manual 3.3.8 AP 0019, Control of Temporary Materials 3.3.9 AP 0021, Work Orders 3.3.10 AP 0042, Plant Fire Protection 3.3.1 1 AP 0502, Radiation Work Permits 3.3.1 2 AP 05 10, Working in Confined Spaces 3.3.13 AP 05 12, Work in Hot Environments 3.3.14 AP 0536,A U R A Implementation for Design Changes and Work Analysis 3.3.1 5 AP 0620, Chemical Material Use in Radiation Control Areas 3.3.1 6 AF 6024, Plant Housekeeping 3.3.1 7 AP 6025, QuaIity Controlflndependent Inspection 3.3.18 Vermont Yankee Safety Manual 3.3.19 Memo, T.C. frask t o B.R. Buteau, "Response t o Category A Commitment Review SURV9011902CM1," dated December 31,1991 3.3.20 Mark I Torus Shell and Vent System Thickness Requirements Vermont Yankee Nuclear Station, Teledyne Engineering Services Technical Report No. TR-7426,December 1990 3-3-21 OP 5250 Original Page 2 of 12

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$5

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k.

NOTES {Cont.)

' 2. Insulation need not be removed t o perform the inspection.

6.1.1 Perform visual inspections of the following drywell surfaces:

6.1.1.1 Interior of Drywell Liner 6.1.1.2 Exterior of Sacrificial Shield Wall 6.1.1.3 Drywell Penetrations 6.1.I .4 Personnel, Equipment and CRD Equipment Hatches 6.1.1.5 Sacrificial Shield Wall Lateral Supports 6.1.1.6 Safety Related Structural Steel 6.1.2 Document the following on WOPF 5250.01:

6.1.2.1 Areas of peeling, loose or bubbling paint or primer greater than 9 sq. in ( 3"x 3").

6.1.2.2 Areas of bare base material.

6.1.2.3 Areas of corrosion which exceed SSPC-Vis 2, Rust Grade 6.

Performed By /

Verified By I 6.1.3 Map those areas identified in Step 6.1.2 and located below elevation 278' on WOPF 5250.01.

6.1.4 Perform visual inspections of the following torus surfaces:

6.1.4.1 Interior of Torus Shelf including areas approximately 1 foot below the water line 6.1.4.2 Interior of Dtywell to Torus Vent Pipes 6.1.4.3 Interior of Ring Header and Downcomers located above the water line OP 5250 Original Page 5 of 12

OPERAnNG EXPERIENCE INFORMATION REVIEW DATE: 12/12/91 TO  : LOPRIORE FROM  : WANCZYK

'

SUBJECT:

CATEGORY A COMMITMENT REVIEW Attached is a copy of commitment: CAR91063MTl This document is being assigned to you for assessment of its importance to safe plant operation and for specific action as indicated in the Additional Instructions below.

Please review the conmpitment, carry out additional instructions, and complete the lower portion of this f o r m a Type B C o d t m e n t RE: LEAK fN CONCRETE REACTOR PEDESTAL, (MS-77)

PER REC.4, CONSIDER INSTALLING A CONE TYPE BARRIER ON THE PENETRATION THAT SLOPES TOWARD CONTAINMENT W A L L TO PREVENT FUTURE LEAKS, SUBMIT THIS COMPLETED FORM AND OTHER RESULTS OF YOUR REVI-EW OPERATING EXPERIENCE P COORDINATOR ( O X ) BY -*-a- ====

Additional Corrective Action Process per VP Corrective Action Guideline si+ CAR c-I Routhe CAR E-] NCR f-I None [./j

=-- PIIS

- Item is complete, well documented; no

- Additional commitment tracking; commitment(s) and due date(s).

required; initiate the fallowing

- Item needs add'l closeout; DB to present to for final closeout.

(DH) Enter date presented: EjlA (OEC) Final closeout received:

-si

.. - . ...

MEMORANDUM This memo. is being sent to inform you that the drip s h i e l d for MS-77 steam drain l i n e was i n s t a l l e d per W.O. 14792-6646.

A memo. from B. A. Trugeon to you, dated 6 / 1 7 / 9 2 , listed two o p t i o n s to choose from. A modified version of option # 2 was chosen f o r i n s t a l l a t i o n (see attached photo's f o r details).

Based on the i n s t a l l a t i o n of the drip s h i e l d , as stated above, it i s recommended that commitment item # CAR91063MT1 be closed out.

I ab

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DIiTE: 1/27/92 FROM: R.J. Wanczgk FILE: 2.1

SUBJECT:

Desiga of Drip S h i e l d Please provide the Maintenance Department w i t h a design o f a drip shield fer ehe Xs-77 steam drain line. A s noted in MEbiC's informal comments, it appears tnat a seismfa calculation 8 Work Order, drawing changes will be requited.

Maintenance presently has a commitment for t h i s item due, 5/15/92. To meet that commitment, and get: t h e s h i e l d fastalled during the outage, it w i l l be necessary to receive the information from Engineering by 2/21/92. If that U a t e is not reasonable, please contact me.

CC: RPL GL- . . ..

89

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MEMOR4NDUM To: D.C. Ghoh Date: 6/17/92 From: B.A. Turgeon I Subject. Penetration X-26Barrier Following ax two options or a barrier on the penetration that slopes down toward containment I (Penetration X-26). The basis for tixis design is recommendation #4 of the Containment

! Pedestal Leak Task Team Final Report. This report recommends that a "cone" type barrier be installed on this line to prevent any future leakage from reaching the wall of containment.

OPTION #1 I! - Fabricate shield as illustrated in the attached drawing. T h i s is to be made of i lightweight sheet metal or alumhum.

I - Attach (weld,rivet) straps to the shield. These straps should be made of sheet metal or aluminum, approximately 1" wide and at least 14" in length. Each free end should be bent at a right angle and drilled to accornodate a nut and bolt to secure this sheild to the pipe.

I Note: This pipe is 18" O.D.,circumference of 56.55" j - Make a 2" wide 3/16" thick rubber gasket. This should be 56 1/2" in length.

- Install shield with tubbex gasket on pipe as shown in the attached sketch.

I - A preliminary estimate from Mercury is $280 (8hrs. for a journeyman) plus materials to fabricate this shield (this does not include installation or gasket).

OPTION $2

- Purchase steel angle flange.

I - 18 1/4" X.D.McMaster-Carr #17641(64 (Pg. 80 of Catalog 94)

I - Cut flange in half.

- Attach (weld,rivet) straps to flange. These straps should be approximately 1" wide and at least 18" in length. Each free end should be bent at a right angle and drilled to accomodate a nut and bolt to secure this flange to the pipe.

- Make a 2" wide 1/4" thick rubber gasket. This should be 56 1/2"in length.

- See attached sketch for diagram.

- The price for this flange from McMaster-Carr is $20 (Does not include additional alterations or gasket).

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I r

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91

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Ball Joints Full Blast Gates For use where an easy moving,. lightweight Control volume and shut off flow ot air or connection IS required. All units are ztnc exhaust gases. Increase suctlon efficrency plated after spinning. on at1 flow pipes.

Used !o< ventilation applications. and air

.Save energv and reduce heating costs.

transmisston and tume collect!on in rnanu- Cast aluminim construction.

facturinG processes. Available in 3' through Install with circular collar on inside of the 1C diameters. Pipe.

Size No. NETEACH Size No. NETEACH Size 3-..............

No. NETEACH

...... site No. NETEACH a' ............1790K26 ......587.24 3"..............1 ~ 8 K l l Sl1.73...... 9 ............

1788K'I7 ......552.06 C ..............

i 7 3 0 ~ i s43.33 1791)K22 ...... 45.56 ............1790Kn......116.33 4n ..............17SBU12 ...... 12.89 10"............1?88KI8 ...... 84.00 5'........... 1790K23

... ...... 50.54 9"

10" ............17901(28 ......718.33 5"..............l788Kt3 ...... 17.24

.............. .....

12' ............1788K19

............ ......

...

95.M b ..............J790K24 ...... 62.22 12' ............179OKO ......'124.49 6" 1788K14. 19.13 1C" ~ 7 8 8 1 +146.30

...

T .........., . , , i m ~ 2...... w............inom......284.80 7" ..............1786K15 .......a. 09 16. ............. 7 8K

.

+ 200.00 5 72.78 8"..............i ~ a ~......

Fabricated steel.

i 635.65 ia" ............ ...

~ 7 ~ 8 ~ 2 251.57 9+

Galvanized Pipe ducers and Increasers Half Blast Gates Reducers and increasers are used when Install in suction and blow pipe lines, !It ovewr adapting to two pipes of different radiuses. outside of pipe. Will cut part of system in O r Out.

Reducers have me crimp$ Connection at Cast aluminum frame. steel slide.

the smaller radius. and increasers are Sire No. NETEACH crimped at the larger radius. r'.............................................. ~789K ........

~ 33.16 Both reduces and increasers are made 4" .............................................. 17891(2........ 15.38 from 28 gauge galvanized steel. 5^ ..............................................17891(3 6"..............................................

........

1789K4 ........ 19-79 15.82 REDUCERS INCREASERS Size 7' to No. NFFEhCH 6".2013K21 .......S7.39 Size No. NETEACH 6" to 7".2013K41 ........S7. 39 7" ..............................................

8'. .............................................

1789~5 ........ 21.67 1 7 8 9 ~ 6........ 24.99 0' to 6" . S 1 3 W ........ 9.13 6" to 8" .2O13K42 ........ 9.13 9" to 6".2013K23 ........ 10.54 6" to 9".2013K43 ........ 10.54 10' to 6'.2013K24 ........ 14.02 6" to lo" .2013K44 ........14.02 Square to Round

12. to fY.2013K25 ........1?37 6" to 12".2013K45 ........ 17.57 Duct Adapters 8* to 9'10

........

~ . 2 o t 3 ~ 2 6 9.13 7.2013K27 ........10.54 T to w.2013Ka ........

7" to 9".20131(47 ........19.54 8.13 Used to access round duct to the main square 1V to 7".20131(28 ........

........

14.02 7" to lW.2013K48 ........14.02 7" to 12".20131(49 ........1787 COLLAR duet Atjapten are constructed of 30 gauge gal-lr to 7.2013K29 ?7.57 vanized steel. Will work on galvanized s t d and 9" lo 8".2013K31 ........1084 8" to 9"...2013KSi ........1064 !flexibleair handling ducts. Available in takwff.

lo' to ir to 8".2013K32 ......

aw.2013~33........17.57

..14.02 8" to 10".2013K52 a" to ir.20131(53

........

........

14.02 1787 male collar, and female collar styles.

Description Size No. NEfLACH lo" to gC.20f3K34 ........14.02 9" to lP.ZD13K54 ........14.02 TakeOff .............. 6" to 7" .........2015K44 ........$5.70 12" to 9",2013K35 ........17-57 9" to 12".ZD13K55........17.57 TAKE-OFF Female Cotkar ....... ...6 ............

Male Collar .............. 6" ............2015K46 2a15K45 ........ 2 2 1

........

12" to 13".2013K36 ........17.57 lo" to 12".2013KS........ llS? 221 Lightweight Steel Angle Flanges 7 Strong, ac- SI=, Inches Hole No. PLAIN PUNCHED curatelyrnade tD H W T 5C Size,ln. Holes No. NET EACH No. NET EACH flanges. Sizes: 3hs ...1 ........ I......%IO ... 4% .... ......... ......

9nt 6 1764KEl .....S5.32 1764K41 ..S5.98 31/rrto5'n6ID flanges are 4'hs ...l ........ ...... ...

5'146 ...l,........l 1

......#IO 5I;b ......

1. 10 ... 6% ....$ !

.........

......... ...

6 ......17EAU62..... 5.65 6... 17641(83.,,,. 6.18 17WK42 6.47 1764K43 ., 7.03

..

pressed steel. ....

6'18 1 /r .....1 k ... k .... 7 1 , ..... ~ .%......... 6 ...... 1764KSl..... 6.93 1764Kll .. ?.60 The remaining

.... .....

8% lk IT/<

..... ...

7% ....l k 1% 'h.... 8%! ......%2

....

... 'le 9%. .....

.........

......... 6 ......1764K52..... 7.53 8 ......1764K53..... 6.13 1764K12.. 7.95 1764K13.. 6.55 flanges are rolled strue-, ....

S k 1') L..

... .....

lOsns l'/d ll/d ...

. '/S....lO!e...... '&

lk ... h...11346 . ....'I tu

......... 8 ......1764K54.

......... .....

8 . 1764K56

....

..... 6.98 7.53 1764K?4.. 7.45 1764K15 .. 7.95 t u ral angle iron. Larger 1% ...1% .....11/4...

...

3'" ....

12%e ...I %!.....I %, R ~ . . .313~6 1 2 % ...."LIZ

~ .........

........ 8 ......1764K56..... 8-80

-12 ......T?w=? ..13.3a ...

17641<16.. 9.43 w ..........

angles. chan- Y ...'3,32 1764K17 ..I424 7..........

nek, bar, and 13% ...I $92 1h... ..... ....

9/6 141%6s..13& ......... 12 ......17646% ..I3.88 ... 1764K18 -14.99 6. .........

...... .....

'.

shapes in 14345...1~h.....1 1 ~ Ynfi ~ .....15~3/16...!~& .........12 17641(59 14.84 1764K19 ..16AO P..........

steel. stainless steel, aluminum, and other 15%6 ...I??! ..... ....

lk... J i 6 161?16...13& ......... ......

16 1764K61 ..? 6.13 ... 1764- ..17.26 1IT .........

materials rolled to specifications, and spe- .....

16'14 ....1?'4 1 k . . 916....1 8 k......?3& ......... ......

16 1764K62.....16.79 1764K22..ia.ia cia1 punchlng are available. Specify ....

1S1/4 13/L.....1%... 3Aa...20%

....

20'14 1?%.....1%... h 6....22 ......'2.

......13&

.........

......

.........16 17MK64 18.86 20 ......1764K66 21.43

.....

.....

1764lt24 ..20.43 1764K26 . . a 9 1 1764K999. Prlces on request Punched flanges have bolt holes Bolts are not included. CODE ID = inside diam-22'h ....134 lk... ..... %6 ....

%'/0 ....1%.....1% ... %e ....2 6 h......%s 24 h......%s .......... 20 ......1764K68.....22.73

......... ......

20 17WK71 23-78 .....

17664K28..24.31 1764K31 ..W.41 Galvan eter. H = height. W = wldth from ID of flange to OD of flange. T = thickness of 26'A 2 .... ........

28'/4 ....2

........ ......

2 .... ..... .........

916 28h

....

2 ......?46 3 0 h......k s

.%6

.........

24 ......1764K73 m88 2 4 ......1764K75.....31.88

..... 17641133 ..30.90 1764K35..34.12 metal e l handlir:

Ilange. BC = bolt circle. 30% 2 .... ........ ......

2 $16 .... 3 2 h.....?he ......... ......

.28 1764K76.....3268 1764K36 34.95 tlons. 11 Of elboM times th High Temperature Boiler Gaskets Pipe.

CRIMF Constructed of wire wovenfiberglass, these high temperature How to Order standard sbes: Determine flange w.idth and 3" to 8".

gaskets are well suited to boiler, handbole, and manhole covers thickness needed. Specify Dimension A and Dimension 8 as to 1C', E as well as tank heads and OthQrapplications. Gaskets are rated shown on dlagram. Standard site range is shown in table below. SPOT

!o 379'F and 180 pounds per.square inch. Caskets are spec\a\iy Custom sizes and shapes are available for all flanges and Hot diF

.reated to stay flat and remain soft and pliable. thickness-. Specify1899K999 or 188tKS9. Prlccs on request and air '

to r,2:

14", 20 I Standard She Range Dimenslon A Dlmenslon R Descriptlon Min. Max. Mtn. Max. No. NETEACH Provld HANDHOLE GASKETS cone at

'4 Flar~ge-~ngThick .. 2'......... 4".. ...........339"....... S ............t8991(312 ......$1.9 Divert

%" Flang+'A" Thick .... 2*.. ....... 4" ..............4".......... S'............1899K513 ...... 2.14 annoya

%" F1ange-k" Thick 2'/2"...... .... 6" ............. 4" .......... 8 ............1899K7l4 ...... 2.85 Confit THICKNESS ' MANHOLE GASKETS q4" FIang+h" Thick .... 9".........12".............12"..........17"............1881K211 ......S6.15 1" Flange-%" Thick..... 10".........12".............14" ..........16"............

l'i4" Flange-V'" Thick .... 10" .........12" .............14" ..........76" ............

1881K413 ...... 7.77 1883K514 ...... 9.67 installa Listed Large MGMASTER-CAI=~P

... . . .. . . , . *.

... . _ . . ....... ..... . . .

' - '7 OPERATING EXPERIENCE INFORMATION RWIEW

%+

r - r DATE: 02/10/93 TO Attached is a copy of commitment: CAR91063MT2 This document is being assigned to you f o r assessment of its importance to safe plant operation and for specific action as indicated in the 6

. AddJtional Instructions below.

Please review the commitment, carry out additional instructions, and complete the lower p o r t i o n of this form.

Type B Commitment RE: LEAK IN CONCRETE =ACTOR PEDESTAL (MS-77).

REVISE OP52SO TO INCLUDE MEC -UP'S AS DETAILED IN CAR91063MEC5. (BEVEL, PAINT, INSPECTION)

Sig. CAR [ -1 Routine CAR] , [ NCR ],I None $3 Department Supervisor Approval:

- Item needs 5Qe add'l closeout; DH to present t o &A qlnb346Cc f o r final closeout.

(DH) Enter date presented: #A (OEC) Final closeout received: Ma

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

- - .

3.2 Administrative Limits I

3.2.1 AP 0125, Rant Equipment Control

__

3.3 Other 3.3.1 -

ANSI N45.2.6 1978 Qualifications of inspection, Examination, and Testing Personnel for Nuclear Power Plants 3.3.2 -

ANSI N5.12 1974 Protective Coatings (Paints)for the Nuclear Industry 3-3.3 -

ANSI N101.2 1972 Protective Coatings (Paints) for Gght Water Nuclear Reactor Containment facilities 3.3.4 -

ANSI N101.4 1972 QuaIity Assurance for Protective Coatings Applied to Nuclear Facilities 3.3.5 Steel Structures Painting Council, Steel Structures Painting Manual, Volumes I and 2,Third Edition, June 1983 3.3.6 ASTM 0 4228-83 Standard Practice for Qualification of Journeyman Painters for Application of Coatings to Steel Surfaces of Safety-Related Areas in Nuclear Facilities 3.3.7 YOQAP-1 A Operational Quality Assurance Manual 3.3.8 AP 0019, Control of Temporary and/or Portable Materials 3.3.9 AP 0021, Work Orders 3.3.10 AP 0042, Plant Fire Protection 3.3.1 1 AP 0502, Radiation Work Permits 3.3.1 2 AP 0510, Working in Confined Spaces 3.3.13 AP 0512,Work in Hot Environments 3.3.14 AP 0536, ALARA lmptemsntation for Design Changes and Work Analysis 3.3.1 5 AP 0620, Chemical Material Use 3.3.1 6 AP 6024, Plant Housekeeping 3.3.1 7 AP 6025, Quality ControlAndependent Inspection .

3.3.1 8 Vermont Yankee Safety Manual 3.3.1 9 Memo, T.C. Trask to 6.R. Buteau, Response t o Category A Commitment Review SURVSO11902CM1, dated I

December 31, 1991 3.3.20 Mark ITorus Shell and Vent System Thickness Requirements Vermont Yankee Nuclear Station, Teledyne Engineering Services Technicai Report No. TR-7426, December 1990 3.3.23 Memo, T.C. Trask to 8.R. Buteau, Responset o Category A Commitment Review CAR9 1063MECEi dated January 25,1993 4.0 PRECAUTlONS

4. I Ensure the requirements of AP 05 10 and AP 05 12 have been addressed by Chemistry and Radiation Protection, t o avoid entry into an unacceptable working environment.

4.2 . Solvent based primers and paints give off flammable vapors when curing. Measures shafl be taken t o ensure that such vapors do not bujidup causing an unsafe situation to develop.

OP 5250 Rev. t Page 2 of 10

-

. . . . . . . . ..- . ........ . . . . . . . . . . . . . . . . . .. I

- -. .

+r 6.1.1.6 Safety Related Structuraf Steel I FORINFO ONLY 6.1.1.7 intersection of Drywell Concrete F l o o k a n d & w u i l . I

[Ref. DwQ,#5920-0233){CAR9 1063MEC5)

Performed By j 6.1.2 Document the following on W O P F 5250.01 :

6.f.2.1 Areas of peeling, loose or bubbling paint or primer greater than 9 sq. in ( 3" x 3%

6.1.2.2 Areas of bare base material.

6.1 2.3 Areas of corrosion which exceed SSPC-Vis 2, Rust Grade 6.

6.1.2.4 Areas of accumulated standing water and dirt at the intersection of the Drywell floor and Drywell waIl.

(Ref. bwg. 5920-0233)(CAR91063MEC5)

Performed By /

Verified By i 6.1.3 Map those areas identified in Step 6.1.2 and located below elevation 278' on W Q P F 5250.01.

6.1.4 Perform visual inspections of the following torus surfaces:

6.1.4.1 Interior of Torus Shell including areas approximately 1 foot below the water fine 6.1-4.2 Interior of Drywe11 to Torus Vent Pipes 6.1.4.3 Interior of Ring Header end Downcomers located above the water line 6.1.4.4 Exterior of Ring Header and Downcomers located inside the torus 6.1.4.5 Torus Penetrations 6.1.4.6 Safety Related Structural SteeI Performed By 1 6.1.5 Document the following on VYOPF 5250.02:

6.1.5.1 Areas of peeling, loose or bubbling paint greater than 9 sq. in (

3" x 3").

6.1 S.2 Areas of bare base metal.

OP 5250 Rev. ?

Page 5 of 10

_.... 1 - . . .. . . . ...... , . ... . .. . I . ..

k,'-I 7

' y 1

/ /

• OPERATING EXPERIENCE INFORMATION REVIEW

-.

DATE: 02/20/92

. _

TO FROM  : BUTEA Attached is a copy of commitment: CAR91063MT4 This document is being assigned to you f o r assessment of its importance to safe plant operation and f o r s p e c i f i c action as indicated in the Additional Instructions below.

Please r e v i e w the commitment, carry o u t additional instructions, and complete the lower portion of this form.

Additional Instructions:

--_-__--------c---------

Type B Commitment . -

Item is complete, well documented; no further tracking required.

-

x d d i t i o n a l ' commitment tracking; commitment(s) and due date(s).

required; initiate the following c a + \ r \ c ~/ mni c~a n~v - \ o d - S \--, -~&.GQ b c G qeno-

%e-&: kQ9loG3 -01

- Item needs add'l closeout; DH to present to FJ4 for final closeout.

(DH) Enter d a t e presented: M (OEC) F i n a l ' closeout received: #

MEMORANDUM The subject CAT A assignment required t h a t BWROG Letter 8997 be evaluated and that recommendations be made as necessary- In response to the assignment the following is offered.

The refueling cavity design at Vermont Yankee includes fully welded stainless steel/carbon construction with a backup channel and seal rupture drain. An alarm system is provided to detect any bellows or drain line leakage-The 4 2 ' diameter drywell to reactor bellows is sealed with a penetration weld and not a gasket. (Oyster C r e e k experienced leakage with their gasket design.) As a backup in the event of leakage in t h e bellows or drain piping, an additional stainless steel water barrier is included a s part of the concrete liner to catch any water. A 3

diameter bellows rupture drain is welded to the water barrier and provides a flow path for any leakage to the equipment drain with an alarm to notify operators in the event of bellows leakage.

The BNROG letter identified that the concern is with "those joints that rely on sealing compounds or gaskets" and t h a t the " s e a l welded joints and the drywell bellows should be good f o r the life of the plant.

It is determined that no additional inspections of the welded reactor to refueling cavity bellows is warranted. Additional inspection of the drywell to torus bellows is a l s o not warranted since adequate surveillance of these components are provided during t h e Appendix J tests.

Baaed upon a detailed review of the subject BWROG letter, previously performed engineering reviews and experiences (see CAR 91-63), Vermont Yankee's physical configuration and the existing detection system for I leakage, THE FOLLOWING IS RECOMMENDED. P

1. qPrRd--*= v

1) ME t C should continue to inspect the sand drains,every ten years, verifying that they are open and functional. This inspection was l a s t performed 9/91 and should be rescheduled for 9/01.

T-C~Eq(0634 m

~ _ _ ~ ~ ~

.. . - . .. . . . . .. .. . . .. .. . . . . . .. . .. . . . . . .. _.. . ..

2) Operations should continue t h e weekly surveillance/walkdown of the inner diameter of the torus at elevation 213' and a check for leakage of t h e sand drain lines. These inspection would quickly identify any

, leakage of water which would find its way to t h e containment.

Approved :

Approved :

Engineering Director

- - -

i

I CAR310 63-01 CAR91063MECl CARY 1063MEC2

~~c\lt9l.063141~.3 CA119lqG3MEC:I

!

CAR93 0 6 3 M ~ ~ 5 C A W 1 0 63MPl CARY 1063MT2

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