ML20035C930
| ML20035C930 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/02/1993 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Rogers, Selin I, The Chairman NRC COMMISSION (OCM) |
| Shared Package | |
| ML20035C927 | List: |
| References | |
| NUDOCS 9304090274 | |
| Download: ML20035C930 (3) | |
Text
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'4 UNITED STATES
,3 NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D.C. 20555 0001
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April 2, 1993 MEMORANDUM FOR: The Chairman Comissioner Rogers Comissioner Curtiss Commissioner Remick Comissioner de Planque FROM:
James M. Taylor Executive Director for Operations
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SUBJECT:
COMANCHE PEAK UNIT 2 FULL-POWER LICENSING (REFERENCE THE MARCH 30 MEMORANDUM FROM THE EDO TO THE COMMISSION) to the subject memorandum discussed information regarding thermo-lag testing primarily from a generic perspective. The staff believes it also important for the Comission to understand the staff's rationale for accepting the thermo-lag installation at Comanche Peak.
Enclosed is a discussion of the staff's rationale for finding the thermo-lag installation at Comanche Peak acceptable.
Originalsigned by James M.Sniszek James M. Taylor Executive Director for Operations
Enclosure:
As stated cc:
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9304090274 930402 PDR ADDCK 0500 6
ADDITIONAL INFORMATION ON THERM 0-LAG HOSE STREAM TESTING COMANCHE PEAK In May of 1992, TU Electric (TV) advised the NRC staff that they were going to conduct a comprehensive fire endurance testing program to qualify their Comanche Peak, Unit 2, Thermo-Lag fire barrier designs. The initial testing methodology was based on the acceptance criteria established by American Nuclear Insurers (ANI) Information Bulletin f5 (79), "ANI/MAERP Standard Fire Endurance Test Method to Qualify a Protective Envelope for Class IE electrical Circuits," July 1979. As a result of the initial tests conducted in June and August 1992, the staff had concerns regarding the use of these criteria in that the criteria allowed the fire barrier test specimen to exhibit signs of barrier burn through, cable damage to occur, and allowed the barrier to be breached during the standard hose (solid) stream test.
Based on the staff's concerns, TU revised their fire testing methodology to eliminate the above concerns.
In a letter dated October 29, 1992, the staff concurred that TV's revised methodology was acceptable.
TV's revised hose stream test applies water through a Il-inch fog nozzle set i
at a discharge angle of 30 degrees with a nozzle pressure of 75 psi and minimum discharge flow rate of 75 gpm. The fog stream is applied to the specimen with the nozzle positioned 5 feet away from the center of the specimen at a pressure of 75 psi for 5-minutes.
NUREG-0800, Standard Review Plan (SRP) 9.5.1, " Fire Protection for Nuclear Power Plants," provides fire protection guidance which the staff finds acceptable with regard to meeting NRC fire protection regulations. An applicant can either follow this guidance or can propose to the staff an alternative method for achieving the level of fire safety required by the regulations. TV proposed an alternative method for hose stream testing. This method and the fire endurance testing acceptance criteria and methodology was found technically correct. The following presents the basis for the staff's acceptance of the TV alternative hose stream testing method:
1.
TV's revised fire endurance testing methodology and acceptance criteria adopted the fog hose stream testing criteria established by SRP 9.5.1 for penetration seals.
2.
The Comanche Peak, Unit 2, fire protection program is based on a
" defense-in-depth concept." The implementation of this program required the establishment of a fire prevention program; controls on ignition sources; fire protection features which provide fire barrier separation between safe shutdown trainn rapid detection cf a fire and smoke condition; automatic and manual fire suppression and control methods; and, fire resistive structural building features.
3.
Comanche Peak, Unit 2, used fire resistive building construction techniques for their safety-related buildings.
In addition, the combustible fire loads associated with safety-related and safe shutdown plant areas at Comanche Peak are generally low.
4.
If a fire were to occur in a safe shutdown area at Comanche Peak, structural building collapse is unlikely due to the fire resistive construction techniques used in the design of these structures.
Therefore, directional loads imposed on these barriers by falling structural objects during a fire is not expected.
Further, these areas are generally protected by automatic sprinkler protection and would actuate in a timely manner to control the fire.
5.
The fire brigade at Comanche Peak is trained in the application of water through fog streams for controlling energized high voltage equipment fires.
In addition, it should be noted that standpipe systems in nuclear power plants follow the design guidance of NFPA 14. This standard requires that the flow pressures at the hose valve where the hose station's manuel fire fighting hose (100 feet) connects to the standpipe be restricted to 100 psi. Note that the friction loss in 100 feet of 1%-inch quality fire hose is approximately 25 psi at a nozzle flow rate of 86 gpm. This would yield a nozzle pressure at the hose stations of 75 psi.
During the November 16-20, 1992, fire protection inspection of CPSES Unit 2, representative interior hose stations were inspected. No playpipe type solid stream nozzles were found. The type of nozzles used were the electrically-safe fog type.
It should be noted, the fog stream application (hose stream test) at 75 psi with a nozzle flow of a minimum of 75 gpm, when compared to the actual in plant hose station pressure and nozzle flow conditions, yields a 11 gpm variance and no variance in pressure. Since there was no variance in pressure, the variance in flow is considered to have a minimal affect on the eroding and cooling affects of water on the test assembly. The staff concluded that the hose stream testing performed by CPSES in their fire barrier testing program was acceptable.
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