ML17229A397

LER 97-004-00:on 970611,discovered Incorrect Original Cable Tray Fire Stop Assembly Installation Was Outside App R Design Basis.Caused by Personnel Error.Hourly Fire Watch Patrols Will Be posted.W/970711 Ltr

ML17229A397
Person / Time
Site:	Saint Lucie
Issue date:	07/11/1997
From:	Frehafer K, Stall J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-97-179, LER-97-004-02, LER-97-4-2, NUDOCS 9707150008
Download: ML17229A397 (7)

Text

( 'A.'l'EQO8. 2 REGULATIO INFQRMATIQN DIBTRIBUTIor~sTEM (RIDE)

! ACCESSION NBR:9707150008 DOC.DATE: 97/07/11 NOTARIZED: NO DOCKET ¹ FACIL'.50-389 St. Lucie Plant, Unit 2, Florida Power & Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION FREHA:ER,K.W. Florida Power & Light Co.

STALL,J.A. Florida Power 6 Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 97-004-00:on 970611,discovered incorrect original cable tray fire stop assembly installation outside App R design basis. Caused personnel error. Posted hourly fire watch patrols.W/970711 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR 'NCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR 'ENCL PD2-3 PD 1 1 WIENSFL ~ 1 1 INTERNAL: ACRS 1 1 AEOD/SPD/RAB 2 2 AEOD/SPD/RRAB 1 1 E T 1 1 NRR/DE/ECGB 1 1 ~KRONE 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 RGN2 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 1 1 NOAC POOREFW. 1 1 NOAC QUEENERFDS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN SD"5(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON T NEEDr FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQJIRED: LTTR 25 ENCL 25

Florida Power & Light Company, 6501 South Ocean Drive, Jensen Beach, FL34957 July 11, 1997 L-97-179 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Re: St. Lucie Unit 2 P~

Docket No. 50-389 Reportable Event: 97-004 Date of Event: June 11, 1997 Incorrect Original Cable Tray Fire Stop The attached Licensee Event Report is being submitted pursuant to the requirement's of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, J. A. Stall l/

Vice President St. Lucie Plant (W)

JAS/KWF Attachment cc: Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant

'Ir707150008 9707iX PDR ADOCK 0500038'P S PDR lllllll iliillllllllllllllllllllllllIlls an FPL Group company

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED SY OMS No. 3160% I 04 Exp)RES 04)3 ore 6 (4.95)

ESTIMATED BURDEN PER RESPONSE To COMPLY WITH THIS MANDATO INFORMATION COLLECTION REGUEST: 60.0 HRS. REPORTED LESSON LEARNED ARE INCORPORATED INTO THE UCENSING PROCESS AND FE BACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMAT LZCENSEE EVENT REPORT (LER) To THE INFORMATION AND RECORDS MANAGEMENT BRANCH IT% F33)

U.S. NUCLEAR REGIAATORY COMMISSION. WASHINGTON, OC 206664KO)

AND TO THE PAPERWORK REDUCTION PROJECT I3160<104), OFFICE 0 (See reverse for required number of MANAGEMENTAND BUDGET, WASHINGTON, DC 20603.

digits/characters for each block)

FACIUTY NAME (1) DOCKET NUMBER 12) PAGE 13 I ST LUCIE UNIT 2 05000389 1 OF4 TITLE I4)

Incorrect Original Cable Tray Fire Stop Assembly Installation Outside Appendix R Design Bases FACIUTY NAME DOCKET NUMBER SEQUENTIAL REVISION MONTH DAY YEAR MONTH DAY YEAR NUMBER NUMBER 05000 FACILITYNAME DOCKETNUMBER 11 97 97 004 0 97 05000 OPERATING MQDE (9) 20.2201(b) 20.2203 (a) (2) (v) 50.73(a)(2)(1) 50.73(a) (2) (viii)

POWER LEVEL (10) 100 20.2203(a)(2) (i) 20.2203(a) (3)(n) 50.73(a)(2) (iii) 73.71 OTHER 20.2203(a)(2)(iii) 50.36(c) (1) 50.73(a)(2) (v) Specify in Abstract below or in NRC Form 3BSA 20.2203(a)(2)(iv) 50.36(c) (2) 50.73(a) (2) (vii)

NAME TELEPHONE NUMBER Seclude Aree Code)

K. W. Frehafer, Licensing Engineer (5611 468-4284 REPORTABLE REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS cAusE sYsTEM coMpoNENT MANUFACTURER To NPRDS 4( ..

, x:,t,;

NkÃ"'9):A MONTH OAY YEAR EXPECTED YEs SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE). X No DATE (15)

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

On June 11, 1997, St, Lucie Unit 2 was in Mode 1 at 100 percent power. Inspection results indicated that, generically, two sided cable tray fire stop assemblies lacked the installation of ceramic fiber between cables within the fire barrier. FPL determined that the as-built configuration of two sided cable tray fire stop assemblies did not meet the tested configuration for a three hour fire rated assembly. All the St. Lucie Unit 2 two sided cable tray fire stop assemblies were declared inoperable.

The apparent cause of this event was due to personnel error during the implementation of design drawings or insufficient design guidance during initial installation. Corrective actions include the posting of hourly fire watch patrols that were established to compensate for the inoperable fire stop assemblies. Repairs or plant modifications will be implemented to restore the affected fire stop assemblies to their required three hour fire rating.

NAC FOAM 366 (4.95)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4-9SI LICENSEE EVENT REPORT (LER)

TfXT CONTINUATION YEAR SEQUENTIAL REVISION ST LUCIE UNIT 2 05000389 2 OF 4 97 004 0 TEXT Ilfmore spaceis required, use additional copies of iVRC Form 366Ai (17l On June 11, 1997, St. Lucie Unit 2 was in Mode 1 at 100 percent power. FPL was investigating discrepancies of two sided cable tray fire stop assemblies identified during previous field surveillances.

Intrusive inspections of the remaining population of fire stop assemblies of this design were in progress to determine the extent of the issue. Preliminary inspection results indicated that, generically, the as-built configuration of two sided cable tray fire stop assemblies lacked the installation of ceramic fiber between cables within the fire barrier. The configuration did not conform to the design drawings and FPL ascertained that the identified field conditions were not previously evaluated during initial construction.

Therefore, the two sided cable tray fire stop assemblies did not meet the tested configuration for a three hour fire rated assembly, as required by the plant 10 CFR 50 Appendix R commitments.

As a conservative measure, all the St. Lucie Unit 2 two sided cable tray fire stop assemblies were declared inoperable based on the preliminary inspection results. Hourly fire watch patrols were established as compensatory measures as required by plant administrative procedures. St. Lucie Unit 1 does not utilize cable tray fire stops of this design, so this condition is only applicable to Unit 2.

A review of the original installation and inspection documentation for the construction of the two sided cable tray fire stop assemblies suggests that the apparent cause of this event was due to personnel error during the implementation of design drawings or insufficient design guidance during initial installation. A contributing cause was that the installation drawings were not clear in specifying that ceramic fiber needed to be installed around each cable in the fire stop assembly.

This condition was discovered during a recent fire stop surveillance. Consistent with the Industry, normal fire barrier inspection criterion is a visual inspection of exposed surfaces checking for voids, gaps, and holes. No intrusive inspections or disassembling of fire barriers are performed. One of the fire stops was located such that a visual inspection was difficult to perform, so the inspector ran his hand around the fire stop to check for voids, gaps, 'and holes. The inspector noted air flow between cables through the assembly. Although air flow was noted during that inspection, routine detection of air flow through a discrepant fire stop is problematic in nature and highly dependent on the existence of a differential pressure across the fire barrier. Even if previous inspections were performed in a hands on manner, a differential pressure could not be assured because of Reactor Auxiliary Building ventilation lineup or door configurations in effect during the inspection.

This condition is reportable under 10 CFR 50.73(a)(2)(ii)(B) because the as found condition of the Unit 2 two sided cable tray fire stop assemblies do not meet three hour fire barrier requirements. The fire barriers are discussed in the Unit 2. UFSAR in chapter 9.5A. The principal design objective of the fire barrier and associated penetration seals is to protect personnel and redundant equipment from the effects of postulated fires in the reactor auxiliary building, to assure the capability to achieve safe shutdown in accordance with 10 CFR 50 Appendix R and BTP 9.5-1 Appendix A. The barriers and associated penetration seals are passive devices and are part of the plant fire protection system.

NRG F0AM 366A I4-95I

C, 4

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4-9SI LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST LUCIE UNIT 2 05000389 3 OF 4 97 004 0 TEXT /Ifmore spece is required, use edditionel copies of NRC Form 366AJ l17)

The ceramic fiber between the cables is an extension of the Marinite board (ceramic fiber board) fire stop face. This ceramic fiber serves to resist heat, flame, and smoke propagation through the fire stop. In conjunction with the flame retardant this is an effective three hour fire rated assembly. (See Figure 1 for typical design details). However, without the ceramic fiber between the cables a path for heat and smoke propagation is provided. This is a small and tortuous path in that the space between the cables is typically small. The heat would still need to travel at least one foot down the tray where the flame retardant is applied, then would enter a large open space in the wall, and would then need to exit through another foot of confined space between cables on the non-fire side of the assembly. Localized hot spots would exist.

The IEEE-383 cables will resist the effects of the increased temperatures and help to prevent the ignition of cable in the non-fire side of the assembly.

The two sided cable tray fire stop deficiencies were evaluated and determined to be not safety significant.

Although'the as-found condition of these cable tray fire stops was not in accordance with the tested and design conditions, and would probably not meet a three hour fire rating without the ceramic fiber between the cables, the installation does provide resistance to fire propagation. In addition, fire protection defense in depth provides an integrated means for mitigating the consequences of a fire, such as the existing smoke detection systems, automatic water fire suppression systems, hose stations, administrative programs that control combustible loading, and operator actions. Based on the above, it is concluded that the health and safety of the public were not adversely affected by the condition of the St. Lucie Unit 2 two sided cable tray fire stop assemblies.

The hourly fire watch patrols were established to compensate for the inoperable two sided cable tray fire stop assemblies as required by plant administrative procedures.

FPL will either rework the associated fire stop assemblies to their original design or develop and implement a new design to restore the degraded barriers to a three hour fire barrier rating.

None.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4 95I LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST LUCIE UNIT 2 05000389 4 OF 4 97 004 0 TEXT (if more spoce is required, uso additional copies of NRC Arm 3MAl I17)

TWO-SIDED CABLE TRAY SEAL IN FLOOR/WALL OPENING FIRESTOP 2" CERAMIC FIBER PLUGS FLAMERETARDANT MARINITE- I BOARD (MJOWO!ee Rot FLAMERETARDANT Figure 1 Typical Two Sided Cable Tray Fire Stop Assembly