ML20073D629
| ML20073D629 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/16/1994 |
| From: | J. J. Barton GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C321-94-2145, GL-92-08, GL-92-8, NUDOCS 9409270346 | |
| Download: ML20073D629 (4) | |
Text
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9 GPU Nuclear CorporaHon Nuclear
=.;t; 88 Forked River, New Jersey 08731-0388 609 971-4000 Wnter's Direct Dial Number:
September 16, 1994 C321-94-2145 U. S. Nuclear Regulatory Commission Att:
Document Control Desk Washington, DC 20555 Gentlemen:
Subject:
Oyster Creek Nuclear Generating Station (0CNGS)
Docket No. 50-219 Additional Information Regarding Generic Letter 92-08, "Thermo-Lag 330-1 Fire Barriers."
This letter provides additional information regarding the status of our evaluation of possible corrective actions for the installed Thermo-Lag fire barrier material in the Reactor Building at Elevation 23 feet, as described in Responses III.B.1, V, and VI of GPUN letter to NRC dated February 10, 1994 (C321-94-2012). Also attached is a revised tabulation of the installed Thermo-Lag 330-1 configurations and quantities previously submitted to NRC in the above referenced letter.
This table has been updated based upon the results of walkdowns completed as of June 1994.
As noted above GPUN had committed to evaluate the feasibility of corrective actions to replace the installed Thermo-Lag fire barrier material in the Reactor Building at Elevation 23 feet. This Thermo-Lag configuration was initially installed with the intent of providing a one-hour fire barrier rating for the stairwell enclosure in the northeast corner of the Reactor Building.
The stairwell enclosure provides zone boundary separation between Reactor Building fire Zones RB-FZ-1E and RB-FZ-IF4 which are within the same fire area.
Fire Zones RB-FZ-lE and RB-FZ-lF4 both contain circuits required for safe shutdown. Consistent with the NRC Safety Evaluation Report conclusion regarding the adequacy of OC fire area boundaries (NRC letter to GPUN dated March 24, 1986) for 10 CFR 50 Appendix R compliance; barriers which L
separate fire zones within the same fire area are not required to meet a one-hour fire barrier rating provided there is reasonable assurance that the boundary separating these zones will prevent a fire on one side of the boundary from affecting safe shutdown circuits on the other side of the boundary.
The existing OC Fire Hazards Analysis Report (FHAR) defines the
)
boundary between these two fire zones as "Bl".
A "Bl" boundary requires that 9409270346 940916 PDR ADOCK 03000219 g
GQuclear Corporation is a subsidia v of General Pubhc Uti%es Corporation h,
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4 C321-94-2145 Page 2 the combustible loading on either side of the boundary be less than 40,000 2
Btu /ft (less than 30 minutes fire duration) and that the boundary consist of non-rated physical barriers with open penetrations sealed or protected with Btu /ft'ppression. The current combustible loadings are approximately 25,000 fire sp 2
in RB-FZ-lE and 2,000 Btu /ft in RB-FZ-lF4, and any open penetrations in these fire zones have been sealed to prevent the spread of smoke and hot gases. The principle combustible in Fire Zone RB-FZ-lE is cable insulation in trays which are protected by an automatic deluge water spray system.
Fire detection which alarms in the control room is also provided in both Fire Zones RB-FZ-lE and RB-FZ-IF4. The stairwell enclosure is constructed entirely of seismically designed structural steel with metal decking in the roof. Thermo-Lag prefabricated 1/2 inch panels are mounted on either side of the structural steel or metal decking, and exposed metal surfaces and gaps are protected with Thermo-Lag trowel grade material or pre-fabricated panels. The Thermo-Lag panels over the metal enclosure meets the requirements of a zone boundary barrier.
Based upon the above evaluation, GPUN has determined that the existing fire zone barrier configuration for the Reactor Building stairwell enclosure is capable of adequately preventing the spread of flame, smoke, and hot gases across it from a fire originating on either side. Since the existing configuration satisfies the requirements of a "Bl" barrier and is not required to be a one-hour rated barrier, the Thermo-Lag 330-1 stairwell enclosure installation is no longer considered within the scope of the Generic Letter 92-08 evaluation program.
The DC FHAR will be revised accordingly.
The remaining Thermo-Lag Fire Barrier configurations continue to be evaluated in accordance with our previous commitments documented in our letter dated February 10, 1994, as referenced above.
i Sincerely, A
g J. J. Barton Vice President and Director, Oyster Creek JJB/DJD/ pip Attachment c: Administrator, Region I NRC Resident Inspector, OC Oyster Creek NRC Project Manager 32194145.LET
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Attachment Total Fire Raceway /
Length Building Area / Zone Rating Dimension (approx)
Purpose Reactor RB-FZ-ID 1 HR Conduit /l" &
335' Linear 1
Meet 10 CFR 50.48 2"
Ft.
or Appendix R to 10 CFR 50.
2.
Achieve Appendix R Physical independence of electrical systems.
3.
Support an exemption to Appendix R.
Reactor RB-FZ-lE 1 HR Conduit /1",
145 Linear 1.
Meet 10 CFR 50.48 1 1/2", 2",
Ft.
or Appendix R to
& 3" 10 CFR 50.
Electrical 315 ft.2 2.
Achieve Appendix R penetration Physical boxes (7) independence of electrical systems.
3.
Support an exemption to Appendix R.
Reactor RB-FZ-lF2 1 HR Conduit /
25 Linear 1.
Meet 10 CFR 50.48 1 1/2" Ft.
or Appendix R to 10 CFR 50.
2.
Achieve Appendix R Physical independence of electrical systems.
3.
Support an l
exemption to Appendix R.
Turbine TB-FZ-11C 3 HR Conduit /
20 Linear 1.
Meet 10 CFR 50.48 4"
Ft.
or Appendix R to 10 CFR 50.
2.
Achieve Appendix R Physical independence of electrical systems.
32194145.tET
Turbine TB-FZ-110 1 HR Conduit /l",
475 Linear 1.
Meet 10 CFR 50.48 1 1/4" Ft.
or Appendix R to l
1 1/2",
2 1/2",
3 1/2", & 4" 2.
Achieve Appendix R Physical independence of electrical systems.
3.
Support an exemption to Appendir R.
Office OB-FZ-6A 1 HR Conduit /2" 20 Linear 1.
Meet 10 CFR 50.48 Ft.
or Appendix R to 10 CFR 50.
2.
Achieve Appendix R Physical independence of electrical systems.
Office OB-FZ-6B 1 HR Conduit /l",
35 Linear 1.
Meet 10 CFR 50.48 3"
Ft.
or Appendix R to HVAC Duct 600 Ft.2 Wrap 2.
Achieve Appendix R Physical Electrical 80 Ft.2 independence of Box electrical systems.
10'x5'xl' 3.
Support an exemption to Appendix R.
i i
i 32194145.LET