ML17334A600

LER 97-010-00:on 971210,use of Teflon Packing on Containment Airlock Door Interlock Shaft Results in Potentially Degraded Condition.Cause Is Still Under Investigation.Telfon Packing Rings Have Been Replaced W/Erdm o-rings.W/980109 Ltr

ML17334A600
Person / Time
Site:
Issue date:	01/09/1998
From:	Blind A, Schoepf P INDIANA MICHIGAN POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-97-010-01, LER-97-10-1, NUDOCS 9801140065
Download: ML17334A600 (5)

Text

CATEGORY 1

~

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9801140065 DOC.DATE: 98/01/09 NOTARIZED: NO DOCKET FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTE. N2QfJR AUTHOR AFFILIATION SCHOEPF,P. Zndiana Michigan Power Co.

BLIND,A.A. Indiana Michigan Power Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 97-010-00:on 971210,use of teflon packing on Containment airlock door interlock shaft results in potentially degraded condition. Cause is still under investigation.Telfon packing rings have been replaced w/ERDM o-rings.

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

ENCL J SIZE:

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL 0

PD3-3 PD 1 1 HICKMAN,J 1 1 INTERNAL: AEO PD/RAB 2 2 AEOD/S PD/RRAB 1 1 1 1 NRR/DE/ECGB 1 1 NRR/DE/EELB 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 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 NRC PDR 1 1 NUDOCS FULL TXT 1 1 E

NOTE TO ALL "RIDS" RECIPIENTS:

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

Indiana Michigan Power Company Cook Nuclear Plant One Cook Place Bridgman, MI 49106 INDIANA NICHIGAN POMMER January 9, 1998 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Operating Licenses DPR-74 Docket No. 50-316 Document Control Manager:

d hh hfll lg bdhdby lblg*bl~ d:

.>> Id~

97-010-00 Sincerely, P~~~

A. A. Blind Site Vice President lmbd Attachment A. B. Beach, Region III E. E. Fitzpatrick P. A. Barrett S. J. Brewer J. R. Padgett D. Hahn Records Center, INPO NRC Resident Inspector

+r~ 8 980'if,40065 980i09 PDR ADQCK 0500033.6 S PDR llllllllllll llllllllllllllllllllllllll

NRC FORM 366 NUCLEAR REGULATORY COMMISSION VED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COHPLY WITH THI INFORMATION COLLECTION REQUEST: 50.0 MRS. FORWAR LICENSEE EVENT REPORT (LER) COMHENTS REGARDING BURDEN ESTIMATE TO TH INFORHATION AND RECORDS MANAGEHENT BRANCH (HNB 7714), U.S. NUCLEAR REGULATORY COMHISSIOH, IIASHINGTON, DC 20555-0001, AND TO THE PAPERWOR REDUCTION PROJECT (3150-0104), OFFICE 0 MANAGEMEHT AHD BUDGET WASHINGTON DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) Page1 of3 Donald C. Cook Nuclear Plant - Unit 2 50-316 TITLE (4)

Use of Teflon Packing on Containment Airlock Door Interlock Shaft Results in Potentially Degraded Condition SEQUEHTIAL REVISION FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR MONTH DAY YEAR NUHBER NUMBER Cook Unit 1 50-315 12 10 97 97 010 -- 00 01 09 98 FACILITY NAME DOCKET NUMBER OPERATING MODE (9) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(iii) 73.71(b)

POWER 0

LEVEL (10) 20.2203(a)(2)(i) 20.2203(a)(4) 50.73(a)(2)(v) OTHER (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) 50.73(a)(2)(viii)(B) and in Text, 2f).2203(a)(2)(v) '3(a)(2)(ii) 50.73(a)(2)(x) NRC Form 366A)

X 50 NAME TELEPKOHE HUMBER (Include Area Code)

Mr. Paul Schoepf, Safety Related Mechanical Engineering Superintendent 616/465-5901, x2408 REPORTABLE REPORTABLE CAUSE SYSTEM COHPONENT MANUFACTURER CAUSE SYSTEH COMPOHENT MANUFACTURER TO NPRDS TO HPRDS EXPECTED SUBHISSION X YES NO DATE 15 02 06 -

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

Qn December 10, 1997, with Unit 2 in cold shutdown, it was determined that the seal for the inner bulkhead interlock shaft of the Unit 2 upper containment airlock consisted of Teflon packing rings rather than the specified EPDM elastomer. As Teflon degrades when exposed to the high radiation levels that could exist inside the containment following a postulated loss of coolant accident, a leakage path from the containment into the airlock compartment could have been opened. This condition was reported via ENS at 1726 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.56743e-4 months <br /> EST the same day in accordance with 10CFR50.72(b)(2)(i), as a degraded condition discovered while the reactor was shutdown.

t.

The root cause for the condition is still under investigation. The Teflon packing rings on the inner bulkhead interlock shaft have been replaced with EPDM o-rings on all of the affected airlocks. Appropriate preventive actions will be put in place once the root cause for the condition is determined.

An evaluation of the impact of the use of Teflon seals in the inner bulkhead interlock shaft concluded that although there could have been increased leakage into the airlock following a postulated Loss of Coolant Accident, the outer airlock bulkhead and its associated sealed door would provide a barrier to excessive radioactive material releases.

Therefore, the condition did not present a significant risk to the health and safety of the public.

NRC FORM 366A NUCLEAR REGULATORY COMHISSION VED BY OHB NO. 3150-0104 EXPIRES 5/3'I/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTION REQUEST: 50.0 NRS.

LICENSEE EVENT CONTINUATION FORWARD COMHENTS REGARDING BURDEN ESTIHATE TO THE INFORHATION AND RECORDS MANAGEHENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION ~

WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150.0104), OFFICE OF HANAGEHENT AND BUDGET WASHINGTON DC 20503.

YEAR SEQUENTIAL REVISION Cook Nuclear Plant - Unit 2 50-316 97 10 00 2OF3 TEXT (if nore space is required. use additional NRC Fore 366A's) (I7)

Conditions Prior to Event Unit 2 was in Mode 6, Refueling Unit 1 was in Mode 5, Cold Shutdown Des ri tlon of the Even During periodic maintenance of the Unit 2 upper containment airlock, the seal for the inner bulkhead interlock shaft was found to consist of Teflon packing rings rather than the specified EPDM elastomer. Teflon would degrade when exposed to the high radiation levels which could exist inside the containment following a postulated Loss of Coolant Accident (LOCA). After deterioration of the rings, a leakage path from the containment into the airlock compartment could have been opened, which could have exceeded the Technical Specification (T/S) leakage requirement.

Leakage from the airlock to the outside would not have been adversely impacted by this condition.

The Unit 2 lower airlock, and the Unit 1 upper and lower airlock interlock shafts were also examined. It was determined that Teflon packing had been used on these interlock shafts as well.

In 1984, the service life of organic materials came into question. As a result, a general refurbishment and upgrade of the airlocks was performed between 1984 and 1989. A change to the airlock drawing issued by Trentec, Inc in June 1988 listed the interlock shaft seal as Grafoil packing. This drawing was received by AEPSC, but there is no record that it was transmitted to the plant for use. The root cause of why the records were not transmitted is still being investigated. This information will be provided in an update to this LER.

Anal sis of the Even On December 10, 1997, it was determined that this condition was reportable under the provisions of 10CFR50.73(2)(ii), as a condition that resulted in the condition of the nuclear power plant being seriously degi~ '-(.'.

The condition was reported at 1726 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.56743e-4 months <br /> EST the same day. This LER is therefore submitted in accordance with 10CFR50.73(a)(2)(ii).

The personnel airlock has two doors in series, and each door is designed and constructed to withstand the design basis containment pressure of 12 psig. The Teflon seals are used to seal a shaft which penetrates the inner bulkhead. The seals are located inside the shaft mechanism. Although Teflon is known to be susceptible to radiation damage, it is unlikely that a complete loss of sealing capability would have occurred because the seals are retained inside the shaft and would still function as a barrier to flow.

Even if there could have been significant flow through the shaft seal, the outer door provides a barrier to increased leakage to the environment outside of the containment boundary. The airlock, which contains both the inner and the outer door, is leak tested in accordance with 10 CFR 50, Appendix J and meets the leakage criteria established in the T/S.

NRC FORM 366A NUCLEAR REGULATORY COMMISSION OVED BY OMB NO. 3150-0104 I EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORHATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT CONTINUATION FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MAHAGEMENT BRANCH (MHBB 7714), U.S. HUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTOH DC 20503.

YEAR SEQUENTIAL REVISION Cook Nuclear Plant - Unit 2 50416 97 10 00 3OF3 TEXT (if cere space is required. use additional NRC Fora 3664 s) (17)

Corrective Action The Teflon packing rings on the inner bulkhead interlock shaft have been replaced with EPDM o-rings for the upper and lower airlocks on both units.

Appropriate preventive actions will be put in place once the root cause of the condition has been determined. These actions, along with the root cause itself, will be provided in an update to this LER.

Failed Cpm onen Iden ification Not Applicable Previous Similar Events To be determined