05000395/LER-1999-014-02, Re Kaowool Fire Barriers Outside 10CFR50 Appendix R Design Basis

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Re Kaowool Fire Barriers Outside 10CFR50 Appendix R Design Basis
ML031840469
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 07/01/2003
From: Byrne S
South Carolina Electric & Gas Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 99-014-02
Download: ML031840469 (4)


LER-1999-014, Re Kaowool Fire Barriers Outside 10CFR50 Appendix R Design Basis
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
3951999014R02 - NRC Website

text

Stephen A. Byme Senior Vice President, Nuclear Operations 803.345.4622 A SCANA COMPANY July 1, 2003 Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555

Dear Sir / Madam:

Subject:

VIRGIL C. SUMMER NUCLEAR STATION DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 LICENSEE EVENT REPORT (LER 1999-014-02)

KAOWOOL FIRE BARRIERS OUTSIDE IOCFR50 APPENDIX R DESIGN BASIS Attached is a revised Licensee Event Report, LER 1999-014-02, for the Virgil C.

Summer Nuclear Station (VCSNS). This report updates the compensatory actions taken and planned in response to the testing results for KAOWOOL triple wrap fire barriers. This issue is being reported per 10 CFR 50.73(a)(2)(ii)(B).

Should you have any questions, please call Mr. Jeffrey Pease at (803) 345-4124.

Very truly yours, Stephen A. Byrne JWPISAB/dr Attachment c:

N. 0. Lorick N. S. Cams T. G. Eppink (w/o attachment)

R. J. White L. A. Reyes K. R. Cotton NRC Resident Inspector K. M. Sutton D. L. Abstance P. Ledbetter EPIX Coordinator INPO Records Center J&H Marsh & McLennan QC NSRC RTS (0-C-99-1 520)

File (818.07)

DMS (RC-03-0131)

SCE&G I Vrgil C. Summer Nuclear Station

  • P. 0. Box 88. Jenkinsville, South Carolina 29065.T (803) 345.5209. www.scana.om

ARC ORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 0613012001 (6-1998) the NRC may not conduct or sponsor, and a person Is not required to respond to. the Information collection.

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~~~~~~~~~SUBMISSION Ii ii l(ifyes, complete EXPECTED SUBMISSION DATE).II DATE (IS) II II ABSTRACT (Umftto 14M spaes, Le., approxiately15singlespaoed typewrtte ons) 16)

On December 28, 1999, Virgil C. Summer Nuclear Station (VCSNS) commissioned testing on Kaowooll triple wrap fire barriers. The testing was conducted to confirm the fire resistance rating of typical plantl specific design considerations.

On December 29, 1999, engineering personnel determined, fr-om a review of preliminary test data, that somel as installed applications may not meet the current regulatory requirements for maintaining one train free of fire damage for one hour. Station Condition Evaluation Report (CER) 99-1520 was generated to documentl this event and to track actions for resolution.l As a result of this test, all surface mounted configurations, and 4" and larger conduit and 6" x 36" racewaysl suspended in open air, passed the l -hour fire rating. Some of the cables in I" conduit, 6" x 6" raceways, and air drop cables suspended in open air failed the Generic Letter (GL) 86-10, Supplement I megger whenl subjected to an ASTM E-1 19 fire test.l VCSNS has implemented compensatory actions (fire watches) as a conservative measure, for all Kaowool Fire Barriers that are needed to achieve and maintain post-fire safe shutdown in accordance withl Appendix R and I OCFR50.48. Adjustments to these compensatory actions will be based on the results ofl further engineering evaluation, and the completion of plant modifications.ll NRC FORM 366 (6-1998)U.S. NUCLEAR REGULATORY COMMISSION (6-1998)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAMEI DOCKET NUMBER 2 LER NUMBER 6 PAGE 3 V. C. Summer Nuclear Station 05000395 YEA NUMBER I

NUMBER 2 of 3 I

1999 014 02 TEXT (If nve space Is requhred, use addational copies of NRC Form 366A) (17)

PLANT IDENTIFICATION Westinghouse - Pressurized Water Reactor EOU3PMENT IDENTIFICATION Kaowool Fire Barrier for Electrical Cables IDENTIFICATION OF EVENT Testing of Kaowool triple wrap fire barriers demonstrates that some applications do not meet design requirements.

EVENT DATE December29, 1999 REPORT DATE January26,2000 SUPPLEMENT 1 REPORT DATE April 1,2000 REVISION 2 REPORT DATE July 1, 2003

CONDITIONS PRIOR TO EVENT

Mode 1, 100% power

DESCRIPTION OF EVENT

Virgil C. Summer Nuclear Station (VCSNS) commissioned fire-endurance testing to be performed on Kaowool triple wrap fire barriers on December 28, 1999. A large scale 1-hour test was conducted at the Omega Test Labs in San Antonio, Texas. The testing was conducted on representative sample conduits and cable trays, in typical VCSNS configurations, to confirm the fire resistance rating of these barriers and verify our existing design and licensing basis. This testing was being performed as a voluntary initiative at the request of the NRC as discussed in SECY 99-204, "Kaowool and FP-60 Fire Barriers."

Engineering personnel determined, on December 29, 1999, that preliminary results indicate that some applications may not meet the current regulatory requirements for maintaining one train free of fire damage for a one hour duration (10 CFR 50 Appendix R, Section III.G.2.)U.S. NUCLEAR REGULATORY COMMISSION (81998)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME 1) l DOCKET NUMBER 2 LER NUMBER 6)

PAGE (3 V. C. Summer Nuclear Station 05000395 YEAR SEIUER l

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~~1999 014 02 TEXT (ffxmoe space Is required, use additional copies of NRC Form 3664) (17)

ANALYSIS Some limited cable failures were identified. The limited failures were experienced in small cable, conduit, and tray applications installed in open-air configurations (not running along wall or ceiling). Other applications; large conduit, tray, and surface mounted conduit performed satisfactorily, based on a preliminary review of the test data.

VCSNS has a total of 30 Kaowool triple wrap applications that are required for Appendix R The 30 Kaowool applications are limited to 18 separate fire areas/zones. Of the 18 fire areas, 14 have fire loads less than the current designed fire rating of the enclosure with the other four located in cable chases that have automatic fire suppression. Additionally, 16 of the affected fire areas, have acceptable core damage frequency, as calculated during Phase 1 of the IPEEE evaluation, with the remaining 2 found acceptable during Phase 2 by fire modeling. In four instances the air drop cables required an additional (2) layers of 1" Kaowool wrap and modifications (ECR-50205) to provide thermal masses above the tested configurations to protect these individual cables.

IMMEDIATE ACTIONS VCSNS has implemented compensatory actions (roving fire watches) for all 30 Appendix R Kaowool triple wrap applications (18 fire areas/zones) as a conservative and precautionary measure.

LONG TERM CORPECTIVE ACTIONS VC Summer has implemented modifications (ECR 50205), based on the results of the engineering evaluations to address affected areas by providing additional protection for exposed silicone foam barriers, exposed supports (potential thermal shorts), and the air drop cables. This change included evaluations resulting in 11 of the 30 Kaowool triple wrap applications meeting all design and licensing basis.

VC Summer is also pursuing additional modifications to address the remaining 19 Kaowool applications, which include re-routing cables, adding suppression, and using a qualified fire wrap material. These changes are intended to bring VCSNS into compliance with existing design and licensing bases. These modifications are scheduled to be completed by December 31, 2005.