05000458/LER-1993-014, :on 930701,installed Sprinkler Sys as Substitute for Passive fire-rated Barrier Due to Deficiency Identified in Fire Barrier Separation Requirements.Declared Fire Barriers Surrounding Valves Degraded

:on 930701,installed Sprinkler Sys as Substitute for Passive fire-rated Barrier Due to Deficiency Identified in Fire Barrier Separation Requirements.Declared Fire Barriers Surrounding Valves Degraded

ML20046C389
Person / Time
Site:	River Bend
Issue date:	08/02/1993
From:	Booker J, Lorfing D GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-014, LER-93-14, RBG-38820, NUDOCS 9308100240
Download: ML20046C389 (6)

LER-1993-014, on 930701,installed Sprinkler Sys as Substitute for Passive fire-rated Barrier Due to Deficiency Identified in Fire Barrier Separation Requirements.Declared Fire Barriers Surrounding Valves Degraded

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(x)
4581993014R00 - NRC Website

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GULF STATES UTILITIES COMPANY NMEFI BEND ST ATION POST Of TICE BOX 220 51 rRANCJSVILLE LOViSLANA 70775 AREA CODE 504 635 fKl94 346 8651 August 2, 1993 RBG-38820 File Nos. G9.5, G9.25.1.3 li U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Gentlemen:

River Bend Station - Unit i Docket No. 50-458 Please find enclosed Licensee Event Report No.93-014 for River Bend Station -

Unit 1. This report is submitted pursuant to 10CFR50.73.

Sincerely, f.

Anbj "J. E. Booker Manager - Safety Assessment and Quality Verification River Bend Nuclear Group JPi #

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U.S.- Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Resident Inspector i

P.O. Box 1051 St. Francisville, LA 70775 INPO Records Center 700 Galleria Parkway Atlanta, GA 30339-5957 Mr. C.R. Oberg Public Utility Commission of Texas 7800 Shoal Creek Blvd., Suite 400 Nonh Austin, TX 78757 r

Department of Environmental Quality Radiation Protection Division P.O. Box 82135 Baton Rouge, LA 70884-2135 ATTN: Administrator 4

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fdRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104

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EST MATED BURDEN PER RESPONSE TO COMPLY WTH TH:S INFORMAT!ON COLLFCTON REQUE ST: 50.0 HR3 TOFMARD LICENSEE EVENT REPORT (LER)

COMME'FS REGARONG BURDEN EsimTE TO THE M ORMMON AND RECORDS MANAGEMENT E8 RANCH (MNB9 77t4L U L. NUCLEAR REGULATORY COMM:ES!ON. W ASHrNGTON. DC 20E55 0001. AND TO 1

THE PAPERWORA REDUCTON PROJECT 1315crO104), OFFICE OF (See reverse for required number of digits / characters for each block)

MANAGEMENT AND BUDGET, WASHtNGTON, DC 205a3.

FACILITY NAME (1)

DOCKET NUMBER (2).

PAGE (3)

RIVER BEND STATION 05000 4 5 8 1 OF 4 nTu t9 Improper substitution of a sprinkler system for passive lire-rated barrier EVENT DATE (5)

LER NUMBER (61 REPORT NUMBER (7)

OTHER FACILITIES INVOLVED (8)

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F AQUTY NAME DUGKE I NUMBEH SEQUENTIAL REVtSiON r

MONTH DAY YEAR YEAR "N"

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E' W MBER NUMBER 05000 i AUUlY NAME DOQTT NUMBER i

07 01 93 93

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OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR O (Check one or morel (11) 7 MODE (9) 1 20 402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

POWER 20.405(a)(1)(i) 50.36(c)(1) 50 73(a)(2)(v) 73.71(c)

LEVEL (10) 100 20 405(a)(1 Ha) 50.36(c)(2) 50.73(a)(2)(vid OTHER 20 405(a)(1)(m) x 50.73(a)(2)(i) 50.73(a)(2)(viii)(A)

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LICENSEE CONTACT FoR THIS LER (12)

NAME TELEPHONE NUMBFH mcWo* Area Gude) t D.N.

Lorfing, Supervisor-Nuclear Licensing 504-381-4145 COMPLETE ONE LtNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTE M COMPONE NT MANUFACTURER

CAUSE

SYSTEM COMDONENT M ANUF ACTURf R pg l

SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONT H DAY YE.AR YEs NEO no pe yes. empire EFECTED SUBM:SQON DATE) x DATE (15)

I ABSTRACT (Limit to 1400 spaces, i e, approximately 15 single-spaced typewntien lines) (16) i On July 1,1993, as pan of a corrective action review of modification requests and associated 10CFR50.59 evaluations, GSU identified a deficiency in fire barrier separation requirements.

Contrary to Branch Technical Position BTP CMEB 9.5-1, a sprinkler. system was installed as a substitute for a passive fire-rated barrier under modification request (MR) 85-0548. From January 10,1989 until a firewatch was established on October 26,1989, compliance with Technical Specification 3.7.7 was not maintained. Therefore, this report is submitted pursuant to 10CFR50.73(a)(2)(i)(b).

Although the installed sprinkler systems are not equivalent to a rated fire barrier the water density provided by the sprinklers furnishes a level of protection sufficient for the fire risk in each fire area.

The hourly firewatch patrols currently in place, provide the proper compensatory action pursuant to Technical Specification 3.7.7 NRC FORM 366 ($ W)

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mU.S. NUCLEAR REGULATORY COMMISSION APPROVED BY oMB NO. 3150-0104 is s.2; EXPIRES 5/31/95 -

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PAGE (31 SEQUENT 1A4.

REVGON ygg NUMBER NUMBER 05000 4 5 8 2OF4 RIVER BEND STATION 93 014 -

00 TLX1 pt enore space os reqwrea, use ea$0orns, coores of Mtc wm 3ESA) (17; REPORTED CONDITION On July 1,1993, GSU identified a deficiency in fire barrier separation requirements. Contrary to Branch Technical Position BTP CMEB 9.5-1, a sprinkler system was installed as a substitute for a passive fire-rated barrier under modification request (MR) 85-0548. From January 10,1989 until a firewatch was established on October 26,1989, compliance with Technical Specification 3.7.7 was not maintained. Therefore, this report is submitted pursuant to 10CFR50.73(a)(2)(i)(b).

LNVESTIGATION Modification request (MR) 85-0548 was written to provide a method of protection, other than fire-rated barrier, for three (3) valves required for the River Bend post-fire safe shutdown methodology.

These valves and their locations are as follows :

D-Tunnel (Fire Area AB-7)

E-Tunnel (Fire Area PT-1) lE12*MOVF068B ISWP*MOV501 A ISWP*MOV096B An unreviewed safety question determination (USQD) was performed and the modification was installed under the provisions of 10CFR50.59. As corrective action for problems with the containment airlocks, GSU has reviewed all MRs and associated USQDs (LER 93-003, supplement 1). During this review effort, problems were identified in MR 85-0548 and in its safety evaluation.

The MR states, "...certain sprinkler densities can equilibrate to hourly fire ratings." However, the use of a " water curtain" as a rated fire barrier has not been endorsed by the National Fire Protection Association (NFPA). A deviation to section C.5.b.(2) of Bmnch Technical Position (BTP) CMEB 9.5-1 such as substitution of a " water curtain" for a rated fire barrier is outside the scope of 10CFR50.59.

A " water curtain" is used as a rated barrier between fire areas in two locations at River Bend Station. However, these applications have been approved and documented in Supplement 3 to the SER (Reference Section 9.5.1.6). The substitution of a " water curtain" for a rated barrier for a single piece of equipment required for post-fire safe shutdown was an incorrect interpretation of the limits to which a modification can be implemented without submittal to the NRC for approval.

Therefom, from suspension of hourly firewatches on January 10,1989 until another firewatch was established on October 26,1989 (Reference CR# 90-1144), neither an acceptable fire barrier nor compensatory action was in place for the above listed valves.

NRC FOAM 366A (5 92)

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PAGE (3)

LEQsJENTA f4EVSiON NUMBER NUVBER 05000 458 3 OF 4 RIVER BEND STATION 93

- 014 00 a mi-,av.c..,.n w..-- - eunC - am on ROOT CAUSE A root cause evaluation was performed using the technique of barrier analysis. The results of the root cause analysis are summarized below.

The engineer who performed the design and prepared the safety determination apparently did not recognize the difference between the use of a water cunain as a barrier between two fire areas, and the use of a water curtain as a barrier to achieve separation between redundant components for post-fire safe shutdown (i.e. Section c.5.b.(2) of BTP CMEB 9.5-1). In the USQD pmpared by the engineer, he stated that the function of both Dre barriers and suppression systems is to contain a Dre. Since a water cunain was allowed elsewhere at RBS as a rated Hre barrier, the engineer applied this substitution to redundant components required for post-Bre safe shutdown. This approach reveals an improper understanding of the extent to which an approved deviation (in this case for fire areas) could be expanded to include post-Gre safe shutdown components under the provisions of 10CFR50.59 and NSAC 125 guidance. Use of a water curtain as a barrier to achieve separation between redundant safe shutdown components requires NRC approval as a deviation from BTP CMEB 9.5-1.

A review of previous LERs revealed none similar.

CORRECTIVE ACTION

Upon discovery of the reponed condition, the fire barriers surrounding the valves in question were declared to be degraded and the identifying condition report was added to the limiting condition for operation (LCO) mquiring hourly firewatches for both fire areas (LCO 93-180). The sprinklers installed appear to be designed in accordance with Standard NFPA 13, " Installation of Sprinkler Systems", Section 5-3.7. However, NFPA 13 does not recognize the use of water spray'as a means to protect a speci6c piece of equipment. A deviation request to BTP CMEB 9.5-1, section C.5.(b).2 will be submitted te d.. "nc far review by November 1,1993.

Intensive training in the prepamtion and review of 10CFR50.59 evaluations has been provided for all engineers within the last year. Engineering supervision has repeatedly emphasized the use of

. NSAC 125 guidance during preparation of USQDs. GSU's increased emphasis on attention to detail j

and technical accuracy of 10CFR50.59 evaluations provides a high level of confidence that this error i

will not be n:peated in the future. In addition, GSU's intensive review of previous 10CFR50.59 evaluations provides confidence that this is the only case of its kind.

NRC FORM St 44 @ 92)

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NRC f ORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5 ea EXPIRES 5/31/95 ESTtMATED BURDEN PER RESPONSE TO COMPLY WCTH TH:S INFORMATON COLLECTON REQUEST: 50.0 HR5 FORWARD LICENSEE EVENT REPORT (LER)

COMuEN s nEGARo,No BuRoEN ESTiuATE TO THE iNrORMiriON TE CONTI UATa y AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U,$. NUCLEAR REGULATORY COMMIS$CN. WASHINGTON, DC 20S55-0001. AND TO 8

8' THE PADERWORK REDUCTON PROJECT (3150 0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON DC 20$03, FACILITY NAME (1)

DOCKET NUMBER (2)

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PAGE(3)

LEQUENTiAL REV! SON yg NUMBER NUMBER RIVER BEND STATION 05000 458 4 OF 4 93 014 00 uxT g, m,,..:,,, r..,,.oa...oo=- c

, or usc % 3e,sy o 73 The fire amas containing the valves will remain under hourly fimwatch patrol pending NRC action on the deviation to the BTP.

SAFETY ASSESSMENT

Although the installed sprinkler systems are not equivalent to a rated fire barrier the water density provided by the sprinklers furnishes a level of protection sufficient for the fire risk in each fire area.

The hourly firewatch patrols currently in place, provide the proper compensatory action pursuant to Technical Specification 3.7.7.

NRC FORV 366A (5 92)