ML17334B741

LER 98-004-00:on 980319,determined That Ice Condenser Bypass Was Potentially in Excess of Design Basis Limit.Caused by Lack of Understanding.Known Degraded Conditions Resulting in Divider Barrier Pass Being corrected.W/980420 Ltr

ML17334B741
Person / Time
Site:	Cook
Issue date:	04/20/1998
From:	Sampson J, Schoepf P AMERICAN ELECTRIC POWER CO., INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-004, LER-98-4, NUDOCS 9804240098
Download: ML17334B741 (10)

Text

CATEGORY 1 REGULATORY INFORMATION DISTRZBUTIO SYSTEM (RIDS)

ACCESSION NBR:9804240098 DOC.DATE: 98/04/20 NOTARIZED- NO DOCKET ¹ FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH.'NAME SCHOEPF,P.

'UTHOR AFFILIATION American Electric Power Co., Inc.

SAMPSON,J.R. American Electric Power Co., Inc.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 98-004-00:on 980319,ice condenser bypass potentially in excess of design basis limits occurred. Caused by unauthorized mods.Known degraded conditions resulting in divider barrier pass being corrected.W/980420 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc. E NOTES: G RECIPIENT COPIES RECIPIENT COPIES ZD CODE/NAME LTTR ENCL ZD CODE/NAME LTTR ENCL PD3-3 PD 1 1 STANG,J 1 1 R INTERNAL: AEOD/SP B 2 '

2 AEOD/SPD/RRAB 1 1 ER 1 NRR/DE/ECGB 1 1 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1' NRR/DSSA/SRXB 1 1 RES/DET/EIB 1 RGN3 FILE 01 1 1 D EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE, J H 1 1 NOAC POORE,W. 1 1 NOAC QUEENER,DS 1 1

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NRC PDR 1 1 NUDOCS FULL TXT 1 1 E

N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERS1ON REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 24 ENCL 24

American Electric Power Cock'tec.'ear P'ant

.'e '.cc( ~'ace 9r;Ccmgan. rtttl -'".'M AAtlERICAN ELECTRIC POWER April 20, 1998 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Operating Licenses DPR-74 Docket No. 50-316 Document Control Manager:

in accordance w'ith the criteria established by 10 CFR 50.73 entitled ~Lic ns e (bggl b fll ig g i big b 98-004-00 Sincerely, Site Vice President Itlm Attachment A. B. Beach, Region III E. E. Fitzpatrick P. A. Barrett S. J. Brewer R. Whale D. Hahn Records Center, INPO NRC Resident Inspector 9804240098 '7r80420 PDR S

ADOCK 050003t6 PDR

NRC FORH 366 . NUCLEAR REGULATORY COMMISSION ROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY MITH THI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORNAR LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO TH INFORHATION AND RECORDS MANAGEHENT BRANCH (HNB 7714), U.S. NUCLEAR REGULATORY COMHISSION, MASHINGTON, DC 20555-0001, AND TO THE PAPERNOR REDUCTION, PROJECT (3150-0104), OFFICE 0 HANAGEHENT AND BUDGET IIASNINGTON DC 20503.

FACILITY NAME (1) DOCKET NUHBER (2) Page1 of4 Donald C. Cook Nuclear Plant - Unit 2 50.316 TITLE (4)

Ice Condenser Bypass Potentially In Excess of Design Basis Limit EVENT DATE 5 LER NUMBER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 8 SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER HONTH DAY YEAR YEAR MONTH DAY NUMBER HUMBER None FACILITY NAME DOCKET NUMBER 03 19 98 98 004 00 04 20 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO 'tHE REQUIREMENTS OF 10 CFR: Check one or mor e 11 HODE (9) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(iii) 73.71(b)

PQlER 00 20.2203 a 1 20.2203 a 3 ii 5073 a 2 iv 73.71o LEVEL (10) 20.2203(a)(2)(i) 20.2203(a)(4) 50 '3(a)(2)(v) OTHER 20.2203 a 2 ii 50.36 c 1 50.73 a 2 vii (Specify in 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(viii)(A) Abstract below 20.2203(a)(2)(iv) 50.73(a)(2)(i) and in Text, 50.73(a)(2)(viii)(B) NRC Form 366A) 20.2203(a)(2)(v) 50.73(a)(2)(ii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER 12 NAME TELEPHONE NUHBER (Include Area Code)

Mr. Paul Schoepf, Safety Related Mechanical Engineering Superintendent 616/465-5901, x2408 COMP L ETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN T HIS REPORT 13 REPORTABLE REPORTABLE CAUSE SYSTEH COMPONENT MANUFACTURER CAUSE SYSTEM COHPONENT MANUFACTURER TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED MONTH DAY YEAR YES SUBMISSION (lf yes, complete EXPECTED SUBMISSION DATE). X NO DATE (15)

ABSTRACT (Limit to 1400 spaces, i,e., approximately 15 single-spaced typewritten lines) (16)

On March 19, 1998, with Unit 2 in Mode 5, cold shutdown, it was determined that the design basis limit of 5 square feet for bypass flow around the ice bed during an accident had been exceed by the cumulative effect of multiple bypass flow paths. This was determined reportable under 10CFR50.72(b)(2)(i), as a degraded condition discovered while the unit is shutdown that, if found while the reactor was operating, would have resulted in the plant being in an unanalyzed condition, and an ENS notification was made at 1422 hours0.0165 days <br />0.395 hours <br />0.00235 weeks <br />5.41071e-4 months <br /> EST. The investigation later determined that the cumulative total did not exceed the design basis value, however, given the number of degraded conditions already identified, it could not be guaranteed that additional unidentified bypass flow paths do not exist. Therefore, this LER is voluntarily submitted in accordance with 10CFR50.73(a)(2)(ii).

The individual bypass conditions are attributed to unauthorized modifications. All known bypass flow paths are being corrected as they are discovered. Preventive actions are being taken to prevent unauthorized and inadvertent design changes, to enhance the recognition of a design change, and to enhance the quality of the design basis and configuration documentation.

The condition was evaluated and it was determined that the safety significance of the known bypass flow paths around the ice bed is negligible. If all known conditions existed simultaneously, and passed flow at their maximum bypass capability, the cumulative effect would have been below the design limit of 5 square feet. Therefore, the health and safety of the public was never in jeopardy.

NRC FORM 366A . NUCLEAR REGULATORY COMMISSION ROVED BY OMB HO. 3150.0104 EXPIRES 5/31/95 E

ESTIMATED BURDEN PER RESPOHSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT CONTINUATION FORWARD COMMENTS REGARDIHG BURDEN ESTIMATE TO I THE INFORMATIOH AHD RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSIOH, WASHINGTON, DC 20555-0001, AHD TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AHD BUDGET WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NUMBER 2 LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION Cook Nuclear Plant - Unit 2 50-316 98 004 00 2 OF4 TEXT (if acre space is required. use addit>ooal HRC Form 366A's) (17)

Conditions Prior o Even Unit 2 was in Mode 5, Cold Shutdown Desc ion f e Even The Cook units are pressurized water reactors with ice condenser containments. The ice condenser containment requires that the steam and air flowing from the lower containment compartment in the event of an accident be routed to the upper compartment via the ice bed. To accomplish this, a structural barrier, called the divider barrier, separates the lower and upper containment compartments. The divider barrier includes the walls of the ice compartment, the upper deck, the compartments enclosing the upper portion of the steam generators and pressurizer, the gate separating the reactor cavity from the refueling canal, and portions of the walls of the refueling canal.

The design basis limits bypass flow around the ice bed to no more than 5 square feet (ft'). The installed bypass through the refueling cavity drains is equivalent to 2.3 ft'. As a result of recent inspection efforts, it was determined that the 5 ft'imitwas potentially exceeded in the past as a result of multiple bypass conditions in addition to the installed bypass. The cumulative effect for the known bypass flow paths had been calculated to be 5.24 ft'. Since it could not be determined how long most of the identified conditions had existed, the bypass flow was conservatively assumed to have concurrently existed.

The degraded condition which was identified which increased the bypass flow above the limit was an area of gray duct tape on the bay 24 end wall. The duct tape appeared to be covering gaps in the sheet metal around conduits penetrating the ice condenser end wall. The gap in the sheet metal was estimated to be 1 ft'ith six separate two inch conduits penetrating the opening. The end wall of the ice condenser in the lower plenum area is a reinforced concrete wall with embedded pipe sleeves for glycol piping penetration and direct embedded conduit penetrations.

After further physical examination of the area behind the sheet metal, it was determined that although a 1 ft'xisted in the sheet metal lagging and the insulation had been patched with gray duct tape, no gaps or openings in the wall were discovered. Based upon the physical configuration of the end wall in the area of the conduits, a 1 ft'ypass path was determined not to exist. Utilizing a nominal two inch diameter and neglecting the cable in the conduits, the maximum potential flow path through the six conduits would be 0.13 ft'. The revised cumulative known divider barrier bypass flow path was therefore 4.37 ft'.

Although the revised bypass flowpath was reduced below the design limit of 5 ft', it was decided that, based on the number of degraded conditions which had been identiTied which resulted in bypass flow paths, the potential exists that unidentified bypass currently exists which would result in a cumulative total of greater than 5 ft'. It was considered significant that the total bypass flow had approached the design basis limit, therefore, this event is being voluntarily submitted as-an LER.

Cause of Event The individual bypass conditions are attributed to unauthorized modifications. The unauthorized modifications created bypass paths via material substitutions, original construction discrepancies, inadequate service life, and unsealing of spare penetrations during the performance of work activities.

Based on the individual deficiencies, it was concluded that the cause of the pattern of degraded conditions was a lack of understanding of the design basis of containment as a system, in combination with a lack of documented configuration and inadequate implementation of the design change control process. All known bypass flow paths are being corrected as they are discovered. Preventive actions are being taken to prevent unauthorized and inadvertent design changes, to enhance the recognition of a design change, and to enhance the quality of the design basis and configuration documentation.

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NRC FORM 366A NUCLEAR REGULATORY COMMISSION ROVED BY OMB NO. 3'l50 0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT CONTINUATION FORWARD COMMENTS REGARDIHG BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MAHAGEMEHT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150.0104), OFFICE OF MANAGEHENT AND BUDGET, WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NUMBER 2 LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION Cook Nuclear Plant - Unit 2 50-316 98 004 00 3 OF4 TEXT (if acre space is required. use additional NRC Fona 366A's) (17)

This condition was determined to be reportable on March 19, 1998, in accordance with 10CFR50.72(b)(2)(i), as a degraded condition discovered while the unit is shutdown that, if found while the reactor was operating, would have resulted in the plant being in an unanalyzed condition, and an ENS notification was made at 1422 hours0.0165 days <br />0.395 hours <br />0.00235 weeks <br />5.41071e-4 months <br /> EST.

Although the investigation later revealed that the known cumulative bypass did not exceed the design limit of 5 ft', this LER is being voluntarily submitted in accordance with 10CFR50.73(as)(2)(ii).

The know bypass flow paths summarized below represent the condition as reported on March 19, 1998:

Open Area in ft'.3 Refueling Cavity Drains Ice Condenser Air Handling Unit line 0.005 2-CPS-209, 2-CPS-210, 2-CPS-244 0.1 Conduit Penetration in ¹22 Steam Generator doghouse 0.087 Conduit Penetrations Using "RTV" Sealant 0.349 Divider Barrier Hatches 1.4 Ice Condenser End Wall Penetrations 1 TOTAL 5.241 As a result of the investigation the end wall penetration open area was reduced, resulting in the total known bypass being reduced below the design limit of 5 ft':

Open Area in ft'.3 Refueling Cavity Drains Ice Condenser Air Handling Unit line 0.005 2-CPS-209, 2-CPS-210, 2-CPS-244 0.1 Conduit Penetration in ¹22 Steam Generator doghouse 0.087 Conduit Penetrations Using "RTV" Sealant 0.349 Divider Barrier Hatches '"1 4 Ice Condenser End Wall Penetrations 0.13 TOTAL 4.371 As a result of the reduction in bypass, it has been concluded that the safety significance of this condition is negligible.

As depicted in the above summary, the total known bypass flow paths result in open area less than the design limit of 5 ft'. Therefore, as the design limit was not exceeded, the health and safety of the public were never in jeopardy.

The known degraded conditions resulting in divider barrier pass are being corrected via corrective maintenance or design changes as they are identified.

To prevent unauthorized or inadvertent design changes, 12 PMP 5040.DCP.001 "Design Change Determination",

has been developed and implemented. To enhance recognition of a design change, 12 PMP 2291.PLAN.001 "Work Control Planning Process", is being implemented. Additionally the UFSAR validation project will enhance the quality of the design basis and configuration documentation.

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NRC F(lRM 366A . NUCLEAR REGULATORY COMHISSION OVED BY OHB NO. 3150-0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY IIITH THIS INFORHATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT CONTINUATION FORHARD COMHEHTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEHENT BRAHCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, NASHINGTON, DC 20555.0001, AND TO THE PAPERIIORK REDUCTION PROJECT (3150.0104), OFFICE OF MAHAGEMENT AND BUDGET MASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NUMBER 2 LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION Cook Nuclear Plant - Unit 2 50-316 98 004 00 4 OF4 TEXT (if more space is required, use additional NC Form 366A's) (IT)

A procedure will be developed to guide inspection of the divider barrier on a refueling outage frequency for possible bypass paths. This procedure will include provisions to ensure that the design basis allowable cumulative bypass is not exceeded, through correction and/or tracking of any identified bypass paths. This procedure will be developed and initially implemented prior to restart from the current outages.

Failed Com onent Identification Not Applicable r vi I arEve s None

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