ML20198N234

Provides Revised Description of Detailed 10CFR50,App R Request for TMI-1 Fire Zone FH-FZ-6,as Previously Submitted to NRC in Util Ltr Dtd 961231.Encl Description Replaces Info Provided in Referenced Ltr

ML20198N234
Person / Time
Site:	Crane
Issue date:	12/23/1998
From:	Langenbach J GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1920-98-20718, NUDOCS 9901060061
Download: ML20198N234 (8)

Text

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GPU Nuclear, Inc.

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Route 441 South Post Office Box 480

' NUCLEAR Middletown, PA 17057-0480 Tel717 944-7621 December 23,1998 1

1920-98-20718 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen:

Subject:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289

'10 CFR 50 Appendix R Exemption Request - Additional Information i

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This letter provides a revised description of the detailed exemption request for TMI-l fire zone FH FZ-6, as previously submitted to NRC in GPU Nuclear letter dated December 31,1996 (6710-96-2418, Enclosure A). The attached exemption request description replaces the corresponding description for fire zone FH-FZ-6 provided in the above referenced letter and reflects the TMI-l commitment to install an automatic wet pipe sprinkler system in this fire zone to enhance the fire protection features in FH-FZ-6. This system will consist of a closed head, wet pipe sprinkler system provided with a locked open manual isolation valve with valve position supervision. The valve position supervision and a water flow switch will provide alarms to a continuously manned location. This description also clarifies that the fire

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pre-plans for fire zone FH-FZ-6 are to be revised to specify that a hose be connected to the j

existing 2 inch fire protection system drain outside this fire zone for fire fighting in FH-FZ-6. The previous description of this fire zone implied that this specification had already existed in the fire j

l Pre-plans.

' Also,'in accordance with previous discussions and NRC walkdowns of fire zone CB-FA-1, it is our understanding that isolating the source of acetylene gas from the 1/2 inch supply line routed through CB-FA-1 when the line is not in use is not required due to the additional risk associated with venting and isolating the line. The sensitivity of the planned acetylene detectors will be adequate to detect and alarm any minimal amount ofleakage.

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9901060061 981223

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PDR ADOCK 05000289 R

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1920-98-20718T Page 2 of 2 :

I TMI-l has completed the Thermo-Lag upgrade modifications in fire zones AB-FZ-3 and FH-FZ-5.

Compensatory measures will be removed from these two fire zones once the effected fire barriers have been restor'ed to operable status. In fire zones ISPH-FZ-1 and ISPH-FZ-2, the Thermo-Lag upgrade modifications for fire barriers outside the scope of the pending 1-hour barrier exemption requests have been completed and baseline Thermo-Lag inspections are in progress. In fire zo_nes CB-FA-2b, CB-FA-2c, CB-FA-2d, CB-FA-2e, CB-FA-2f, CB-FA-2g, CB-FA-3a, and CB-FA-3b,

- the Thermo-Lag upgrade modifications have been completed and the additional detection system

' : modification and baseline The_rmo-Lag inspections are in progress. TMI-l remains on schedule to complete the Thermo-Lag effort by December 31,1999, as previously approved by NRC in confirmatory order dated May 22,1998.

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. If additional information is required, please contact Mr. David J. Distel, OPU Nuclear Licensing

-and Regulatory Affairs at (973) 316-7955.

Sincerely, Ms James W. Langenbach

' Vice President and Director, TMI Att:, Fire Zone FH-FZ-6 Description

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.cc: ' Administrator, Region I TMI Senior Resident Inspector TM1-1 Senior Project Manager File No. 94032 t

ATTACHMENT FIRE ZONE FH-FZ-6 (Ref. Dwg.l?o. FH-FZ-6)'

FIRE ZONE DESCRIPTION (Information taken from TMI-l FIRE HAZARDS ANALYSIS REPORT).

a.

FIRE ZONE FEATURES Fire Zone FH-FZ-6 is locah M on elevation 285' of the Fuel Handling Building. Area dimensions are approximately.45 feet x 20 feet x 20 feet high. Zone boundaries consist of reinforced concrete walls, floor and ceiling. The east boundary is a three hour rated boundary. The north and south boundaries are not adjacent to any other plant areas. The west boundary is adjacent to fire zone FH-FZ-1 which is provided with an automatic wet pipe sprinkler system. The floor is not adjacent to any other plant areas. The ceiling is adjacent to zone FH-FZ-2 which is provided with an automatic wet pipe sprinkler system.

b.

COMBUSTIBLE MATERIALS AND LOCATIONS The principal insitu combustibles in this area, excluding Thermo-Lag, is minor amounts of tube oil which is contained in the two chilled water compressors and instrument air compressors. There is a negligible amount of exposed cable insulation in this zone. The installed Thermo-Lag itself has been added to the combustible inventory in this Fire Area.

The overall fire loading is considered low,9,247 BTU /FT2 (reduced from 11,695 BTU /FT2 due to removal of some Thermo-Lag material during Mecatiss upgrades).

Tnermo-Lag constitutes approximately 70% of this load. This total fire loading corresponds to a fire severity on the ASTM E-119 curve of between 8 and 9 minutes.

Note that TMI-l has administrative controls over transient combustibles and work in the plant.

c.

FIRE PROTECTION FEATURES Fire protection for this Fire Area consists ofionization smoke detection which actuates an alarm in the' control room. A 2" drain connection from the fire protection system is located in the stairwell outside this fire zone. Fire pre-plans are being revised to specify that a hose be connected to this drain for fire fighting in this zone. A portable dry chemical extinguisher is also located outside this fire zone in the stairwell. An area wide c

automatic wet pipe sprinkler system will be added to augment existing fire protection features.

The aforementioned fire protection features will be maintained by the surveillance program required by the TMI-l license condition.

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) Based upon actual experience,15 minutes is estimated for the full fire brigade ~ complement to bring manual suppression to bear on a fire in this fire area. This assumes the fire -

brigade is in full turnout gear with self contained breathing apparatus. Note there is no i

radiological hazard in this area that could impede fire fighting operations or fire brigade response.:

i l A previous exemption was granted for the requirement for an area-wide fire suppression.

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- system as documented in an SER, Letter No. 5211-87-3066, Joha F. Stolz to Henry D.

O, Hukill dated March 19,1987. This previously granted exemption will no longer be applicable based on the commitment to install an automatic wet pipe sprinkler system in -

j FH-FZ-6.

id; SAFE SHUTDOWN CIRCUITS AND EQUIPMENT The specific safe shutdown circuits and equipment protected by the existing Thermo-Lag fire barriers in this fire zone are associated with the following functions:

. iMake-up Supporting Function e 'RCS Pressure

. Reactor Coolant Pump Thermal Barrier Cooling e'

Steam Generator Pressure and Level e

o' - Source Range. Monitoring i

Electrical Power System These functions require fire barrier protection in order to insure a safe shutdown path if a fire eliminates all other unprotected circuits and equipment in this fire zone. This assumption served as the basis for protecting the above functions in this fire zone.

P The following information describes the layout and function of the protected safe shutdown circuits in this fire zone. Drawing FH-FZ-6 depicts safe shutdown circuit

! routings for the various functions. This drawing also depicts circuit routings for

- redundant or alternative unprotected safe shutdown circuits. These are not exact routings but rather show the general paths of the various circuits. As noted below the protected circuits are routed in rigid steel conduit and are protected by envelopes which have a fire _

j i endurance rating (ACTUAL) of at least 50 minutes and a cable qualification rating of at

~ least 60 minutes.-

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1920-98-20718 Page 3 of 6 ENVELOPE ICCC-FB01 Cables for the following functions are protected by this envelope which runs west to east and passes approximately 10 feet over the Control Building chilled water units:

Make-up and Supporting Functions

• RCS Pressure Reactor Coolant Pump Thermal Barrier Cooling ENVELOPE ICCC-FB02 A cable for Reactor Coolant Pump Thermal Barrier Cooling is protected by this envelope which nms west to east and passes approximately 10 feet over the Control Building chilled w'ater units.

o ENVELOPE ICCC-FB04 Cables for the Electrical Power System are protected by this envelope which runs west to

' cast and passes approximately 10 feet over the Control Building chilled water units.

ENVELOPE ICCC-FB05 A cable for the Electrical Power System is protected by this envelope which runs west to east and passes approximately 10 feet over the Control Building chilled water units.

SNVELOPE ICCC-FB07 A cable for Source Range Monitoring is protected by this envelope which nms west to east and passes approximately 10 feet over the Control Building chilled water units.

THERMO-LAG DESCRIPTION 4 -

The following Thermo-Lag fire barriers are the subject of this exemption request. The TMI-l FHAR currently requires these fire barriers to have a one hour fire endurance (Actual) rating:

ENVELOPE TYPE.

' ACTUAL:

CABLE

- NEl

- NO.c

. RATING

QUALL TEST RTG..

ICCC-FB01 4" Conduit 50 60 2-1 1CCC-FB02 4" Conduit 50 60 2 ICCC-FB04 4" Conduit 50 60 2-1 ICCC-FB05 4" Conduit 50 60 2-1 1CCC-FB07 4" Condulet 50 60 2-1

'1CCC-FB07 4" Conduit

-50 60 2-1

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e. EVALUATION FIRE HAZARDS ANALYSIS j

- Ths technical requirements of Appendix R, Section Ill.G.2 are not met because the above Thermo-Lag electrical raceway fire barrier envelopes in this fire zone are not rate.d at one i

hour as per the requirements of N~RC Generic Letter 86-10 Supplement 1. The combustible materials present in the area consist oflube oil contained in the chilled water units, minor amounts of piping insulation with a low flame spread rating and Thermo-Lag I

which represent a fire load of 9,247 BTU /FT2. A fire that directly impinges on the fire -

barrier envelopes is unlikely here even if the planned area wide automatic wet pipe '

sprinkler system fails to function as the envelopes are located at the ceiling while the lube oilin the chilled water units and compressors is about 10 feet below the envelopes. The

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compressors are located about 20 feet north of the envelopes.

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The potential for fire exposure in this fire zone to the Thermo-Lag envelopes isjudged to be less severe than the conditions experienced in the ASTM E-Il9 test. The overall volume of the room is substantial enough to dissipate the energy from a localized fire.

n The envelopes will not be challenged by direct flame impingement by this fire as the chilled

. water units and air compressors are not close enough to.directly impact them should a fire occur. Note that envelope ICCC-FB07 is shielded from below by conduits. Room ventilation will continue to run in the event of a fire in this fire zone. Fire preplans 3

proceduralize manual shutdown of the ventilation system, depending upon the extent and s

severity of the fire.

The results of ASTM E-119. testing have been used to assign an actual rating of at least 50 4

minutes to the Thermo-Lag fire barrier envelopes in this fire area. The conditions created

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by potential fires discussed above and the effects of such fires upon the fire barrier

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envelopes in question would not exceed the severity of an ASTM E-Il9 exposure on the

. same envelope, In addition, evaluation has shown that the envelopes will remain structurally intact after an ASTM exposure of one hour and that after 60 minutes of such

. exposure, the temperature inside the envelopes will not affect the ftmetionality of the safe shutdown circuits protected by the envelepe. Therefore, the cable qualification rating of these envelopes is equal to the original intent which was to protect the safe shutdown

' circuits from an ASTM E-Il9 exposure of one hour. It is conservatively estimated that it will take 15 minutes upon receipt of an automatic fire detection system alarm to bring

'. manual suppression to bear on a fire in this room. This is significantly less than the barrier j

. actual rating and cable qualification rating of the fire barrier envelopes within this zone of 1

150 and 60 minutes, respectively, L

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This fire zone lacks significant quantities oflube oil.~ Further, the poter+ial localized -

1 exposure'to these fire barrier envelopes is not considered more severe than the exposare i

of a'n ASTM E-119 test. The fire brigade can be expected to reach the area and ~

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! commence suppression activities within 15 minutes of detection of a fire. Therefore, a

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' cable qualification rating of 60 minutes, with existing detection, manual suppression and a

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planned area wide automatic wet pipe sprinkler system is adequate to protect the safe i

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U shutdown circuits inside the fire barrier envelopes in this fire zone.

SUMMARY

-FIRE ZONE FH-FZ-6 This fire zone is enclosed by reinforced concrete walls, floor and ceiling. The east

. boundary is'a 3-hour rated boundary. The west boundary is not maintained as a rated fire t

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. boundary but the boundary is protected by an automatic wet pipe sprinkler system in the adjacent fire zone. Fire protection consists of an ionization smoke detection system and a y

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portable extinguisher is located outside the area. An area wide automatic wet pipe i

I sprinkler system will be installed in this fire zone. While a hose station is not provided in the stairwell directly outside this fire zone, fire pre-plans will specify the hook-up of a hose to a 2" drain connection on the fire protection system which is located directly outside this zone. The detection system provides early warning capability for potential fires in this area and provides reasonable assurance that a fire will be discovered early on. The i

automatic wet pipe sprinkler system also ensures that fire exposure to the Thermo-Lag raceways in this area will be minimized by containing the fire before the fire brigade can arrive to extinguish it. A fire in this zone is not expected to be severe enough to result in

'significant damage and exposure to the Thermo-Lag fire barrier envelopes in this area.

The cable qualification rating of 60 minutes is considered adequate to protect safe shutdown circuits from damage in the event of a fire in this area. The cable qualification rating of 60 minutes achieves the original intent of providing a one hour barrier in that the safe shutdown circuits inside the barrier will function after exposure to a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> ASTM

= E-119 fire exposure. Further, the potential exposure to any barrier is not considered

- more severe than the exposure of the ASTM E-119 test. Since the severity of the exposure does not exceed that of the. ASTM E-Il9 test, a 60 minute cable qualification rating is considered adequate since the fire brigade can be expected to reach the area and commence suppression activities within 15 minutes of receipt of an automatic fire

detection system alarm. This is significantly less than the barrier cable qualification rating

_ of 60 minutes.

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CONCLUSION-FIRE ZONE FH-FZ-6

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!GPU Nuclear concludes that an alternate fire protection configuration in fire zone ~

l FH-FZ-6 consisting of cable raceway fire barrier envelopes with a Thermo-Lag fire endurance rating of 50 minutes and a cable qualification rating of 60' minutes, an area wide j

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ionization smoke detection system and an area wide automatic wet pipe sprinkler system

. will provide reasonable assurance that one safe shutdown train will be free of fire damage.

This configuration will achieve an acceptable level of protection equivalent to that of i

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r Appendix R,Section III G.2. Therefore, the safe shutdown circuits protected by these envelopes in fire zone FH-FZ-6 will maintain the ability to perform their function in the

event of a fire because the fire would not be of significant magnitude and duration to l

breach the protection provided by the existing envelopes before the fire self extinguished, is extinguished by the automatic wet pipe sprinkler system, or was put out by the plant fire brigade. The control of transient combustibles, the automatic ' detection and sprinkler system,' and the ability of the plant fire brigade to bring manual suppression to bear on a firein this area within 15 minutes are considered adequate fire prevention and fire fighting measures to minimize the effects of a fire in this area thus insuring the ability to achieve safe shutdown in the event of a fire in this area.

Based on this conclusion, the request for exemption from the requirement for electrical raceway fire barriers to have " ACTUAL" fire endurance rating of one hour in fire zone

FH-FZ-6 should be granted since this evaluation demonstrates that the cables protected by these envelopes will continue to function after being exposed to an ASTM E-Il9 fire of at

-least 60 minutes.

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