ML20211A808

Safety Evaluation Supporting 811001,841218,850111,0304 & 0805 Requests for Deviations from App R Fire Protection Features

ML20211A808
Person / Time
Site:	Sequoyah
Issue date:	05/29/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20211A814	List: ML20211A808
References
NUDOCS 8606110363
Download: ML20211A808 (35)

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s SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION APPENDIX R DEVIATION REQUESTS SEQUOYAH UNITS 1 & 2 l

By letters dated October 1, 1981, December 18, 1984, and January 11. March 4, and August 5,1985, the licensee (TVA) submitted requests for NRC approval of 22 deviations to the requirements of 10 CFR 50 Appendix R.

The enclosure of the October 1,1981, letter requested two deviations from the technical requirements of 10 CFR 50 Appendix R, Section III.G. Enclosures 1 and 2 to the December 18, 1984, TVA letter requested two deviations from the technical requirements of 10 CFR 50 Appendix R, Section III.0 and 13 deviations from the technical requirements of 10 CFR 50 Appendix R Sections III.G and III.L.

respectively.

In addition, the enclosure to the January 11, 1985, TVA letter requested five additional deviations from the technical requirements of 10 CFR 50 Appendix R. Sections III.G and III.L. Section 2.C.(13)c of the Unit 2 operating license requires TVA to comply with Section III.G, III.J, III.L. and III.0 of Appendix R of 10 CFR 50, except where NRC has approved deviations to the requirements.

NRC approval of these deviations are required to permit Sequoyah Units 1 and 2 to be in compliance with the license condition.

This evaluation is for 22 deviation reqJests from the technical requirements of Appendix R.

The deviation request regarding separation requirements for safe shutdown circuits inside containment was withdrawn by TVA letter dated March 19, 1986; and the deviation request regarding T-cold instrumentation in the auxiliary control room is still under review due to additional information provided by TVA letters dated March 19 and May 2,1986. The other twenty deviation requests are approved. All deviation requests are discussed and evaluated in the following sections.

Based on this evaluation, it is concluded that, with the exception of the deviation request regarding T-cold instrumentation in the auxiliary control room, and upon completion of the applicable proposed modifications, sufficient fire protection features will be provided to achieve a level of protection equivalent to the applicable requirements of Appendix R.

The following modifications are to be completed as part of the justification for the requested deviations:

a.

Raceways containing redundant circuits for component cooling water pumps to be relocated to afford a 20 feet separation or a one-hour fire barrier to be provided for one of the redundant circuit trains. (See Section III.G, paragraph 2 of this evaluation.)

b.

Automatic sprinkler protection to be provided beneath mezzanine below ERCW valves 1 and 2-FCV-67-146. (See Section III.G. paragraph 5 of this evaluation.)

c.

Automatic sprinkler protection and smoke detectors to be provided above the ceiling area in the radio-chem laboratory and counting room.

(See Section III.G. paragraph 7 of this evaluation.)

0606110363 060529 PDR ADOCK 05000327 F

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Additional protection to be provided for unprotected floor opening between auxiliary building elevations as follows:

sprinkler system water curtain for stairwells; relocation or provision of fire barriers for -

redundant raceways near HVAC duct floor penetrations; and, sealing or capping of conduit penetrations.

(SeeSectionIII.G, paragraph 9ofthis evaluation.)

e.

Provision of circuit protective devices and installation of open head automatic water spray system for redundant cables in 480V shutdown board rooms.

(See Section III.G paragraph 10 of this evaluation.)

f.

Provision of additional sprinkler coverage for areas where existing ceiling level sprinkler system has appreciable obstructions.

(See Section III.G, paragraphs 11 and 13 of this evaluation.)

g.

Provisions of sprinkler coverage in areas where inter.ening cable trays are located between redundant circuits which are not enclosed within a fire rated enclosure.

(See Section III.G, paragraph 13 of this evaluation.)

h.

Provision of a causality procedure for use of jumpers, wire lifts, and fuse replacement if needed to restore the control room ventilation system if lost due to a fire within the auxiliary building.

(See Section III.G.

paragraph 14 of this evaluation.)

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i i III.G - FIRE PROTECTION OF SAFE SHUTDOWN CAPABILITY

1. FIRE DETECTION AND SUPPRESSION SYSTEMS NOT PROVIDED THROUGHOUT THE CONTROL BUILDING DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.3 which requires fire detection and fixed fire suppression system in areas, rooms, or zones for which alternate shutdown capability is provided.

DISCUSSION The control building for which alternative shutdown capability is provided is a fire area separated from adjacent fire areas by construction features having an equivalent three-hour fire resistant rating. Fire detection is provided throughout the control building except for stairs C1 and C2 which are enclosed by construction having an equivalent fire resistant rating of li hours.

Interior fire hose standpipe systems and portable extinguishers are provided throughout the building. Fixed fire suppression is provided throughout the building, except for the control room and several nonsafety-related rooms such as the stairs, corridors, battery rooms, and relay rooms which have low combustible fuel loading. The largest fuel load for the rooms which do not have a fire suppression system is 30,000 Btu /fte, This equates to a fire severity of only 23 minutes. Alternative shutdown methods utilizing the remote alternative shutdown panel located in the auxiliary building is available in the event of a fire within the control building complex. -

The licensee justifies the deviation based on the following: availability of the alternative shutdown capability to assure plant shutdown; three-hour

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separation provided between the control building and location of remote shutdown panel in the auxiliary building; low fire loading; complete fire detection coverage, except for stairs; fixed fire suppression systems for areas having appreciable combustible fuel loads; availability of interior fire hose and standpipe system and portable fire extinguishers; and, prompt response by the plant fire brigade which should assure that any fire will be extinguished quickly without major fire damage.

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EVALUATION The control building is not in compliance with Appendix R,Section III.G.3 because fire detection and suppression systems are not provided throughout the control building fo which alternative shutdown capability is provided.

This protection is required to limit the severity of a fire such that nonnal shutdown components will receive ininimal fire damage and the fire will not damage both the normal shutdown components ar.d the alternative shutdown components. The Sequoyah control building is separated from the auxiliary building by construction features having a l

fire resistant rating equivalent to three-hours. This separation should I

assure that the alternative shutdown capability, which is located within l

the auxiliary building, will not be damaged by fire in the control building. The continuously manned control room, fire detection system l

i i provided for the control building, fixed fire suppression systems for areas having an appreciable combustible fuel load, the interior fire hose system and portable fire extinguishers should ensure early fire detection, I

and prompt fire brigade response and extinguishment in the event of fire.

i This should assure that major fire damage to normal shutdown components will be minimal.

CONCLUSION Based on our evaluation, we conclude that the fire protection features provided for the control building will achieve an acceptable level of protection equivalent to that required by Appendix R, Sections III.G.2 and III.G.3. Therefore, the licensee's deviation is granted.

2. COMPONENT COOLING WATER PUMPS NOT PROPERLY SEPARATED DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R Section III.G.2.c which requires that one train of equipment necessary for safe shutdown be separated by a continuous one-hour fire rated barrier in addition to area protection by automatic fire detection and suppression systems.

DISCUSSION The five component cooling water system pumps are located adjacent to each other on elevation 690' of the auxiliary building. The two Train "B" pumps are separated from the two Train "A" pumps and the spare pump by a one-hour fire rated barrier which extends from the floor to three feet above the highest point of the pumps. The high ceiling height in this area of 23 feet and the large room volume of 429,000 ft2 should dissipate the thermal effects of a fire. A fire detection and automatic pre-action sprinkler system, activated by a cross zone fire detection l

system, are provided for the area.

The combustible fuel load for the area has been calculated by the licensee to be 42,050 Btu /ft2 This is due to the cable insulation in open ladder type cable trays and the 66 gallons of lube oil associated with these pumps and two adjacent auxiliary feedwater pumps. The licensee proposes the following modifications:

Relocate the raceways containing the redundant circuits for the pumps to afford a separation of 20 or more feet or to provide a one-hour fire barrier for one of the redundant circuit trains.

The licensee justifies the deviation for the lack of a one-hour fire barrier between the pumps due to:

limited combustible fuel load; partial height fire barrier partition; high ceiling height and large room volume to dissipate thennal effects of a fire; early detection by area fire detectors; and, the provisions of a fixed fire suppression system.

EVALUATION

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The component cooling water pumps do not meet the separation and fire protection requirements of Appendix R,Section III.G.2 in that one pump i

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• train ccmponent is not separated from the redundant pump train components by construction features having a one-hour fire resistant rating. However, the redundant pumps are separated by a one-hour fire rated partial height partition wall; also, fire detection and automatic sprinkler protection are provided for the area. The combustible fuel load in the area is low and the high ceiling and large room volume should dissipate the thmnal effects of a fire. The licensee is to provide modifications for the raceways containing redundant circuits for the pumps to separate these circuits by 20 or more feet or enclose the redundant circuits for one train within a one-hour fire barrier. The existing fire protection, and construction features, and completion of proposed modifications should provide sufficient protection to assure that one shutdown train will remain free of fire damage in the event of a fire.

CONCLUSION Based on our evaluation, we conclude that upon completion of the proposed modifications the fire protection features provided for the component cooling water pumps will achieve an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2. Therefore, the licensee's deviation request is granted.

3. FIRE DAMPERS NOT PROVIDED FOR POST ACCIDENT SAMPLING FACILITY HVAC DUCT PENETRATIONS DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2.a which requires that redundant shutdown components be separated by a fire barrier having a three-hour rating.

DISCUSSION The walls and floors of the auxiliary building gas treatment fan room are equivMent to three-hour rated barriers, but post-accident sampling facility HVAC duct penetrations through these barriers do not have fire dampers as required to prevent passage of smoke and fire through the fire barriers.

Each gas treatment fan room is a fire zone which contains safe shutdown components and is separated frcm one of the two sampling facility rooms and from the nitrogen storage room by reinforced concrete construction equivalent to three-hour fire-rated barriers. The Unit I gas treatment fan room has two 12-inch, one 10-inch, and one 8-inch round HVAC ducts that passes through it for a short distance. The Unit 2 gas treatment fan room is similar except there are one 12-inch, one 10-inch, and one 8-inch round ducts passing through it. One 12-inch duct ties inte each of the filter systems in the rooms. These ducts are seismically supported.

Pipe sleeves are provided where the ducts penetrate the barrier walls.

The annular space between the sleeves and the pipes are sealed with silicon foam which was installed per manufacturer's instructions.

• The only significant in-situ combustibles in the fire drea including the sampling facility and nitrogen storage rooms are two charcoal filter units located in the nitrogen storage room. This equates to a combustible loading of 780 Btu /ftr. These rooms are provided with fire detectors and the sampling room has an automatic sprinkler system.

Interior fire hose stations and portable fire extinguishers are also available.

Fire barrier tests conducted by two testing laboratories, Underwriters Laboratories, Inc. and Factory Mutual, involving schedule 40 pipe ducts and silicon foam installed similar to the installation at this location satisfactorily passed a three-hour fire endurance test. Due to the low fire loading in these rooms, the licensee's analysis assumes that the pipe ducts for this installation should likewise not fail.

TVA justifies this deviation based on the following: low combustible fuel load within the area; and, fire detection and fixed fire suppression systems installed to provide early fire warning and extinguishment. Also, the pipe ducts used in the HVAC fire tests did not fail; therefore, since the installed HVAC pipe ducts are similar to those tested, they likewise should not fail. The only effect of a fire in one of the sample facility rooms or in the nitrogen storage room which could be expected in the ABGTS room would be radiant heat due to hot gases passing through the ducts. The absence of fixed combustibles in the inanediate area of the ducts provides a high degree of assurance that this radiant heat will not be a threat to safe shutdown components located in the gas treatment fan room.

EVALUATION The post-accident sampling facility rooms which contain safe shutdown components are not in compliance with Appendix R Section III.G.2.a because the HVAC duct penetrations through the three-hour fire barriers are not provided with three-hour fire rated dampers.

The HVAC duct penetrations through the fire barriers are schedule 40 pipe.

Fire tests by two testing laboratories found that pipes installed in this configuration would withstand a three-hour fire test. Therefore, it appears that duct pipes in this location should also endure a three-hour fire situation.

Furthennore, the fire loading in the rooms under consideration is low and the installed fire detection and suppression systems within the area should assure early detection and extinguishment in the event of fire. The construction features and fire protection systems provided for these rooms under consideration should prevent damage to redundant shutdown trains and assure that one train will remain free of fire damage in the event of fire.

CONCLUSION Based on our evaluation, we conclude that the construction and fire protection features provided for the post-accident sampling facility rooms achieve an acceptable level of protection equivalent to that

. required by Appendix R Section III.G.2.a; therefore, the licensee's 4

deviation is granted.

4. TOTAL AREA FIRE SUPPRESSION SYSTEM NOT PROVIDED FOR BATTERY INVERTER AND CHARGER ROOMS DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2 which requires fire detection and automatic fire suppression systems in areas containing redundant safe shutdown equipment that is separated by less than three-hour fire rated construction.

DISCUSSION Rooms 749.0-A2 and 749.0-A15 contain redundant vital battery inverters and chargers and the trained reactor vent and motor operated valve (MOV) boards for Units 1 and 2, respectively.

The portion of the rooms between column lines A6-A8/q-r and A8-A10/q-r are not covered by a sprinkler system.

These rooms are separated from each other and other areas of the auxiliary building elevation 749.0 by reinforced concrete walls which are equivalent to at least a li hour barrier. This is an adequate level of separation considering the combustible loading of the two rooms and has previously been accepted by NRC in an SER dated February 1980.

The only in-situ combustible located in the area without suppression is the insulation on the cables inside the inverters and chargers. A pre-action sprinkler system actuated by cross-zoned ionization smoke detectors covers the remainder of each room. The smoke detection system is provided throughout the area including the area not having the suppression system.

Inadvertent operation of a sprinkler system would cause unacceptable damage to the inverters and battery chargers. Standpipe and hose systems and portable extinguishers are also provided in the rooms.

EVALUATION The fire protection features provided for the battery inverter and charger rooms 749.0-A2 and A15 do not meet the technical requirements of Appendix R Section III.G.2 in that portions of these rooms are not covered by an automatic sprinkler system. These rooms are separated from each other and other areas of auxiliary building elevation 749 by construction which has an equivalent fire resistant rating of 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />. This separation appears sufficient based on the low fire loading and suppression system provided.

These areas were found acceptable during a previous NRC review as documented in the SER of February 1980. The unsprinklered areas of these rooms were not provided with sprinkler protection due to concern that inadvertent operation of a sprinkler system would cause unacceptable damage to the w

< inverters and battery chargers. However, these areas are provided with automatic smoke detectors which should in the event of fire provide prompt notification for early extinguishment by the plant fire brigade. The fire protection features provided should assure that one shutdown train would remain free of damage in the event of fire.

CONCLUSION Based on our evaluation, we conclude that the fire protection features provided for the battery inverter and charger rooms provide an acceptable level of protection equivalent to that required by Appendix R Section III.G.2 and the licensee's deviation request is granted.

5. INADEQUATE SEPARATION PROVIDED BETWEEN EMERGENCY RAW COOLING WATER (ERCW)

VALVES DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R Section III.G.2.b which requires that cables and equipment and associated nonsafety circuits of redundant trains are to be separated by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.

In addition, fire detector and automatic fire suppression systems are required to be installed in the area.

DISCUSSION ERCW valves 1 and 2 - FCV-67-146 are only 15 feet and 8 feet, respectively from their redundant counterpart auxiliary power circuits. These valves are located in the discharge header of the component cooling water system heat exchangers and are located above a mezzanine in room 714.0-Al of the auxiliary building. The only undesirable condition that could result from a transient combustible fire in the mezzanine area is for the valves to spuriously close. However, the component cooling water system must only supply cooling water to a small amount of equipment required for safe shutdown during a fire and TVA has determined that these valves may remain closed for up to two hours. This is sufficient time to manually open any of the valves which might have spuriously closed.

The room is provided with fixed automatic sprinkler systems actuated by ionization smoke detectors.

Standpipe and hose stations and probable extinguishers are also provided for this area. The licensee proposes to provide additional sprinkler heads under the mezzanine.

The in-situ combustible loading for this room is 114,500 Btu /ftr.

Insulation on the cables routed in trays account for 113,500 Btu /fte and the remaining 1000 Btu /fte is,1ue to lube oil in various water chillers and pumps located throughout the room. None of the chillers or pumps are located under these valves. The existing ceiling level sprinklers will provide direct water impingement on the valves.

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. The licensee justifies the deviation for the inadequate separation between the ERCW valves based on the lack of combustible material beneath the valves and due to the fire protection features provided and proposed for this area. Also, should these valves spuriously close they may remain closed for up to two hours without introducing any safety concerns. This is sufficient time to permit fire extinguishment and to manually reopen any of the valves which may have closed. This should assure that the plant may be safely shutdown in the event of fire.

EVALUATION The separation between two of the redundant ERCW valves does not meet the technical requirements of Appendix R,Section III.G.2.b in that the valves are separated by less than 20 feet from their redundant counterpart auxiliary power circuits. The valves and auxiliary power circuits are located above a mezzanine. Fire detection and automatic sprinkler protection is provided at the ceiling and the licensee proposes to install additional sprinklers beneath the mezzanine. The combustible fuel load in the area is low and minimal combustible materials are located beneath the mezzanine. The licensee's analysis indicates that even if these valves should spuriously close, they may remain closed for up to two hours without introducing any safety concerns. This should be sufficient time to pennit fire extinguishment and to manually reopen any valve that may have spuriously closed. The existing fire detection and sprinkler systems and proposed modifications to the sprinkler system should assure that no major damage would occur in the event of fire and safe plant shutdown should be accomplished.

CONCLUSION Based on our evaluation, we conclude that upon completion of the proposed modifications, the fire protection features provided for these ERCW valves will achieve an acceptable level of protection equivalent to that required by Appendix R Section III.G.2. Therefore, the licensee's deviation is granted.

6. INADEQUATE SEPARATION BETWEEN REDUNDANT POWER CABLES TO DIESEL AUXILIARY BOARDS DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R Section III.G.2.b which requires that fire detection and automatic suppression be installed in the area where separating cables, equipment, and associated nonsafety circuits of redundant trains are separated by a horizontal distance of more than 20 feet.

DISCUSSION Cables IPL4982B and IPL4985B (nonnal supply for 480V Diesel Auxiliary Boards IB1-B and 182-B, respectively) are routed in trays on the refueling floor that are 32 feet from trays containing redundant cables 2PL4975A and

2PL4978A (ncrmal supply for 480V Diesel Auxiliary Boards 2Al-A and 2A2-A, respectively). An automatic fire detection system is provided for this area, but there is no fixed suppression system in this room. These cables are located 54 feet above the floor.

The licensee's analysis indicates that a transient combustible fire will not damage these cables and justifies this position and deviation request due to the very low fixed combustible load, large room volume and high ceiling, with location of trays 54 feet above the floor.

EVALUATION The separation between the redundant power supplies to four of the diesel auxiliary boards does not meet the technical requirements of Appendix R,Section III.2.b in that, these redundant power cables are located within the same fire area, separated by more than 20 feet with a fire detection system provided for the area, but no fixed fire suppression system is provided as required.

These redundant cables are located in trays approximately 32 feet apart and 54 feet above the floor. A fire detection system is provided which should provide warning of fire for early detection and suppression by the plant fire brigade using the available portable fire extinguishers and interior fire hose system. Due to the low combustible fuel loading, large room area, high ceiling and fire detection system, a fire within this area should be detected and extinguished prior to both trains being damaged by fire.

CONCLUSION

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Based on our evaluation, we conclude that the construction and fire protection features provided for the refueling floor and these power supply cables provide an acceptable level of protection equivalent to that required by Appendix R Section III.G.2; therefore, the licensee's deviation request is granted.

7. INADEQUATE SEPARATION BETWEEN REDUNDANT ERCW AND FIRE PUMP CABLES DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2 which requires redundant safe shutdown components to be separated from each other by one of the following methods:

Separation of cables and equipment and associated nonsafety circuits of redundant trains by a fire barrier having a three-hour rating.

Separation of cables anc equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

, Enclosure of cable and equipment and associated nonsafety circuits of one redundant train in a fire barrier having a one-hour rating.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

DISCUSSION Power cables for both redundant divisions of the ERCW pumps, fire pumps, ERCW pumping station transfonners, and related circuits are routed in a conduit bank through a corner of the refueling water storage tank (RHST) pipe chase and over the suspended ceiling in the counting room between column lines Cl-A1/t-u on elevation 690.0. The Train A circuits are routed in half of the conduits and Train B circuits are routed in the other half of the conduits. These conduits do not have adequate spacial or barrier separation, or a complete fire suppression system.

The RWST pipe chase.is enclosed by reinforced concrete construction that is equivalent to three-hour fire-rated barriers, except for the end that opens into the auxiliary building. There are no in-situ combustibles located in the pipe chase.

Access limitations ensure that transient combustibles in the pipe chase will be negligible. Access to the pipe chase requires a Radiation Work Permit (RWP) which controls access and work activities in the chase.

Access to the chase is up a ladder and across the roof of the turbine driven auxiliary pump room. The automatic sprinkler system for elevation 669.0 of the auxiliary building protects the entrance of the chase from an exposure fire 1n the auxiliary building.

The fire load for the Radio-Chem Lab and Counting Room (RCL-CR) is low (less than 6 lb/fte). The rooms are provided with preaction sprinklers actuated by cross-zoned ionization smoke detectors.

In addition, a standpipe and hose system and portable extinguishers are provided throughout the plant. The RCL-CR is continuously manned, and any fire in this area should be detected quickly and extinguished.

To further ensure that a fire in the RCL-CR will not damage circuits routed in these conduits, TVA has proposed tha following modifications:

Installation of a sprinkler system to cover the area above the suspended ceiling in the CR.

Installation of smoke detectors above the ceiling area to actuate the suppression system.

This part of the suppression system will provide direct water impingement on the conduits and will also cool the hot gases from a fire.

The licensee's analysis justifies this deviation request based on the low combustible fuel load in the area, and the existing and proposed fire detection and suppression systems which in the event of fire should provide early fire detection for fire brigade suppression or suppression by the automatic sprinkler system.

l EVALUATION A number of redundant shutdown related cables located on elevation 690 of the auxiliary building do not meet the technical provisions of Appendix R Section II.G.2 due to the lack of required spacial or barrier separation or complete fixed fire suppression coverage.

These cables are located within a pipe chase which is void of combustibles, access to which will be controlled by a radiation work permit, and are located in a concealed space in the cc.11ng above the chemistry laboratory.

The laboratory is provided with a pre-ac. tion sprinkler system activated by a smoke detector system. The combustible fuel load within the laboratory is low. To provide additional protection for the cables within the concealed ceiling space above the laboratory, the licensee has proposed to provide sprinkler and detector coverage for the space. The low fuel load in these areas and the existing and proposed fire detection and sprinkler systems for the laboratory area should provide sufficient protection to assure that one safe shutdown train will remain free of fire damage in the event of fire.

CONCLUSION Based on our evaluation, we conclude that upon completion of the proposed modifications, the fire protection features provided for this portion of the auxiliary building will achieve an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2. Therefore, the licensee's deviation request is granted.

8. UNPROTECTED OPENINGS IN FIRE BARRIERS SEPARATING ERCW PUMPS DEVIATION REQUEST TVA requested deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2 which requires redundant safe shutdown components to be separated from each other by one of the following methods:

Separation of cables and equipment and associated nonsafety circuits of redundant trains by a fire barrier having a three-hour rating.

Separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

Enclosure of cable and equipment and associated nonsafety circuits of one redundant train in a fire barrier having a one-hour rating.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

- DISCUSSION Redundant safe shutdown circuits located in the ERCW pumping station are not separated in literal compliance with the requirements.

There are unprotected openings in the interior walls of the pumping station and the roof of the building is of open grating type construction.

The ERCW pumping station is separated into three compartments by reinforced concrete construction that is equivalent to three-hour fire-rated barriers.

Four Train B pumps are located in the center compartments with two Train A pumps in each of the outer compartments.

In-situ combustibles in each of the compartments consist of 39 gallons of lubricating oil within each pump and three gallons of lubricating oil within each traveling screen motor.

The lubricating oil has a flashpoint of 432*F making it difficult to ignite in an unconfinea spill.

l There are two 6-inch diameter scupper holes and one 30-inch by 20-inch hole for a trash ~ sluice in each of the two interior walls that separate i.h redundant pumps. The floors in the outer compartments are sloped so that normal drainage flows away from the inner walls and flamable liquid from a spill will drain into the gutters within the respective compartments.

A flammable liquid spill in the center compartment would enter the gutters and drain to the sump without entering the outer compartments. The open roof configuration would dissipate the heat from a fire, thereby eliminating any significant heat transfer to any of the adjacent compartments.

The trash sluice is of steel construction on three sides and covered with open grating except where the traveling screens discharge into the sluice. The sluice is enclosed on all four sides at these locations. The sluice runs from the northernmost compartment through a 20-inch by 30-inch opening in both interior fire rated barriers and leaves the building through the exterior south wall where it discharges into a 36-inch diameter downspout.

The traveling screens are each capable of discharging a maximum of three oil igniting is improbable due to its high flashpoint (possibility of the gallons of lubricating oil into the trash sluice. The 432*F). However, if the oil was ignited, it would be contained while traveling down the sluice and would discharge into the downspout. The thermal effects of this type of fire would be dissipated through the open grating roof and would not pose an unacceptable threat to the pumps.

Smoke detectors are provided within each electrical equipment room and a heat detector is located above each ERCW pump.

Interior fire hose stations and portable fire extinguishers are provided for the pumping station.

. TVA's justification for this deviation is based on the above construction features which should prevent fire damage to redundant pumps. Thus, one train would be available for plant shutdown.

EVALUATION The ERCW pumps are not separated as required by Appendix R,Section III.G.2 due to several small scupper holes and a small trash sluice in the fire barrier walls between the redundant pumps.

As noted in the above discussion, the construction of the floors should prevent a flamable or combustible liquid spill from involving both pump trains. The flashpoint of the lubricating oil associated with the equipment in the pump station is high (432*F) which makes ignition from an oil spill very improbable. However, if the oil from a spill did ignite, the oil would be contained within the drainage system and the thennal effects of the fire would be dissipated through the open roof grating.

The construction features provided for the pump station should, even in the event of fire, provide sufficient protection to assure that one ERCW pump train would remain free from fire damage.

CONCLUSION Based on our evaluation, we conclude that the construction features provided for the ERCW pumping station provide an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2 and the licensee's deviation request is granted.

9. UNPROTECTED FLOOR OPENINGS IN THE AUXILIARY BUILDING DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2.b which requires redundant safe shutdown components to be separated from each other by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.

In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

DISCUSSION Floor slabs in the auxiliary building necessary to separate redundant safe shutdown components have unprotected penetrations. Consequently, some redundant safe shutdown components that are separated by these floor slabs may not be in literal compliance with the separation requirements of Appendix R,Section III.G.2.b.

The auxiliary building is a designated fire area and is separated from adjacent fire areas by reinforced concrete construction that is equivalent l

to three-hour fire-rated barriers. The auxiliary building is further divided into It hour fire rated enclosures. However, not all

. floor slabs within the auxiliary building are designated as complete fire barriers. They are constructed of reinforced concrete that is equivalent to three-hour fire rated barriers except for equipment hatch openings, stairwells, unsealed spare conduit sleeves, and unprotected HVAC duct penetrations. All other floor penetrations have an equivalent three-hour fire seal. Unprotected floor penetrations in the vicinity of redundant safe shutdown components are proposed to be protected by the following modifications:

Stairwells - A water curtain designed in accordance with NFPA 13, Section 4-4.8.2 will be provided for stairwell openings located near column lines A4/5 and A12/S through floor slabs 690.0 and 714.0.

HVAC ducts - Redundant safe shutdown components located on different elevations near unprotected HVAC ducts will be separated in accordance with Appendix R,Section III.G.2.

Conduit penetrations - Spare conduit sleeves are to be capped on each end by threaded conduit plugs to prevent flames or hot gases from propagating through these capped sleeves. All other conduits that pass through required floors are to be sealed.

These modifications will ensure that no single fire can expose more than one train of safe shutdown components located on different elevations.

The rooms containing the required safe shutdown components that are separated from their redundant counterparts by the floor slabs are protected by fire detection and automatic fire suppression systems.

In addition, standpipre and hose systems and portable extinguishers are also provided.

TVA's justification for this deviation is based on the position that after the above described modifications are complete, the level of protection that will be achieved by locating redundant safe shutdown components on different elevations is equivalent to the separation requirements of Appendix R,Section II.G.2.b.

l EVALUATION The redundant safe shutdown components on different floor elevations of the auxiliary building are not separated as required by Appendix R,Section III.G.2 due to unprotected penetrations in the floor slabs between each elevation. However, as noted above, the licensee has proposed to provide additional protection for these openings. Sprinkler system water curtains will be provided for the open stair shafts. Conduit penetrations will be sealed, and redundant equipment adjacent to HVAC ducts will be relocated to provide the required separation. Upon completion of these modifications, the protection provided by construction of the floor slabs and protection afforded by the floor openings should provide sufficient protection to assure that one safe shutdown train will remain frea from fire damage in the event of fire.

A

. CONCLUSION Based on our evaluation, we conclude that upon completion of the proposed modifications, the fire protection features provided for the open floor penetrations within the auxiliary building will achieve an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2. Therefore, the licensee's deviation request is granted.

10. UNPROTECTED REDUNDANT SHUTDOWN CIRCUITS LOCATED WITHIN SHUTDOWN BOARD ROOMS DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2.c which requires that cables and equipment and associated nonsafety circuits of one redundant train be enclosed in a fire barrier having a one-hour rating and that fire detectors and an automatic fire suppression system be installed in the fire area.

DISCUSSION Train A safe shutdown circuits are routed in trays that pass through 480V shutdown board room 182-B, and Train B safe shutdown circuits are routed in trays that pass through 480V shutdown board room 2A2-A. These redundant circuits are not enclosed in a fire barrier having a one-hour rating.

The auxiliary building is a designated fire area and is separated from adjacent fire areas by reinforced concrete construction that is equivalent to three-hour fire rated barriers. The 480V shutdown board rooms are located on elevation 734.0 of the auxiliary building and are separated from adjacent rooms in the auxiliary building by reinforced concrete construction that is equivalent to 11 hour1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> fire-rated barriers.

The in-situ combustible loadings within 480V shutdown board room 1B2-B is 152,496 Btu /fte and within 480V shutdown board room 2A2-A is 158,136 Btu /ftz. This is due to the insulation on the cables in trays. The licensee proposes the following modification to assure that an internally generated cable tray fire will not be creditable:

Provision of circuit protective devices (breakers and fuses) that l

will clear a fault on a cable before the cable insulation reaches its auto-ignition temperature.

Therefore, the threat to the cables would have to be from an exposure fire due to transient combustibles. The type and quantity of transient combustibles allowed through these rooms are minimized by plant procedures.

If transient combustibles were present and did ignite, the fire would be detected by the ionization smoke detectors and extinguished or controlled by the fixed automatic suppression systems in the rooms or by the plant fire l

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l n.

. brigade. However, to further ensure that a transient combustible fire will not damage ooth redundant trains of circuits, the licensee proposes the following modification:

Installation of open head automatic water spray systems for the protection of Train A trays located in 480V shutdown board room 182-B and the Train B trays located in 480V shutdown board room 2A2-A. Each system will be actuated by a line type thennal fire detection system. The line type thermal detectors will be located at the top and the bottom of the protected stack of trays.

To enclose the cable trays within a one-hour fire-rated barrier would require major modifications to large HVAC ducts and their supports, fire protection piping and supports, and cable tray supports.

TVA's justification of this deviation is based on the position that the addition of.the open head water spray systems will provide a level of protection that will adequately address the hazards present and ensure that one train of redundant safe shutdown circuits will remain free of fire damage.

EVALUATION The Train A and B 480V shutdown board rooms do not meet the technical requirements of Appendix R,Section III.G.2.c in that these rooms contain safe shutdown circuits from the redundant train which are not enclosed within a one-hour fire-rated barrier.

The licensee's analysis indicated that enclosing the raceways containing the redundant shutdown circuits would require major modifications to large HVAC ducts, fire protection piping and cable trays.

In lieu of providing this enclosure, the licensee proposes the installation of an open head automatic water spray system for the raceways in each shutdown board room which contain redundant shutdown circuits. This water spray system in conjunction with the existing area fire detection and fire suppression system should assure that one shutdown train will remain free from fire damage in the event of fire within one of the shutdown board rooms.

In addition, the provision of the circuit protective devices should eliminate the potential of fire from auto-ignition of the cables.

CONCLUSION Based on our evaluation, we conclude that, upon completion of the proposed modifications, the fire protection features provided for the 480V shutdown board rooms will achieve an acceptable level of protection equivalent to that required by Appendix R Section III.G.2.c.

Therefore, the licensee's deviation request is granted.

. 11. PROTECTION OF INTERVENING COMBUSTIBLES BETWEEN REDUNDANT SHUTDOWN CABLES SEPARATED BY MORE THAN 20 FEET DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R Section III.G.2.b which requires that cables, equipment and associated nonsafety circuits of redundant trains be separated by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards and that fire detectors and an automatic fire suppression system shall be installed in the fire area.

DISCUSSION The auxiliary building has open ladder-type cable trays located between redundant cables that are or will be separated by more than 20 feet. The insulation on cables in these trays is consic'ered an intervening combustible material.

The locations in the auxiliary building where redundant cables are spacially separated have no significant in-situ fire hazards present except for the cable insulation in the cable trays. Fuse and breaker coordination provides adequate protection to clear any electrical fault from a cable before its insulation reaches its auto-ignition temperature. Therefore, an internally generated cable tray fire is not considered a credible event. An exposure fire at the floor represents the only significant fire hazard for the redundant cables.

The presence of the intervening cable trays between redundant cables is a concern for two reasons. First, the exposure fire could ignite the insulation which would add to the fire's thermal plume. Second, they could provide a path for the fire to propagate from one train of redundant l

cables to the other. TVA addresses both concerns by relying on the ceiling level sprinkler systems and supplemental sprinkler protection provided to compensate for the intervening combustibles.

Sprinkler coverage has been provided at the ceiling in the rocms where redundant circuits are spacially separated. These sprinklers will release large quantities of water in well developed patterns at the ceiling during a fire. The cooling effect of this water will prevent the fonnation of a heat plume and will control room temperatures until the fire brigade can respond and extinguish the fire.

The licensee has developed criteria for proposed use in the evaluation of the existing installed spinkler systems to verify that the systems will provide sufficient coverage at the floor level. The licensee proposes to provide additional sprinkler coverage when appreciable obstructions to the discharge pattern exist, as outlined by the sprinkler system acceptance criteria.

1

o 1 The objective of the sprinkler system acceptance criteria is to provide compensation for the lack of a horizontal distance of more than 20 feet free of intervening combustibles between redundant divisions. This compensation is provided by installing supplemental sprinkler protection for floor level combustibles when adequate coverage by ceiling level sprinklers cannot be verified. This criteria shall be applied as follows when redundant divisions are separated by horizontal space and more than 20 continuous feet of the space is not free of intervening combustibles.

If the redundant divisions are greater than 30 feet apart, the criteria shall be applied to any continuous 30-feet-wide path located between the redundant divisions.

If the redundant divisions are greater than 20 feet but less than 30 feet apart, the criteria shall be applied to the entire horizontal space between divisions.

TVA justifies this deviation request based on the position that existing sprinkler systems coupled with additional sprinkler coverage resulting from the above criteria will provide a level of protection that adequately compensates for the presence of intervening combustibles located between spacially separated redundant safe shutdown cables and that the intent of Appendix R,Section III.G.2.b will be satisfied.

EVALUATION Shutdown related cable raceways for Trains A and B in the auxiliary building are to be, separated by more than 20 feet, but the area between the raceways is not free of intervening combustibles as required by Appendix R,Section III.G.2.b due to installation of open ladder-type i

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cable trays which contain cable insulation that is considered combustible.

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To compensate for the intervening combustibles, the licensee proposes to rely on the existing ceiling level sprinkler systems with supplemental sprinkler systems to be provided for areas where the ceiling level system is not considered effective as noted in the above discussion section.

The proposed modifications will assure adequate sprinkler coverage for the horizontal area between redundant shutdown trains from either the ceiling level rprinkler systems or from a combination of the ceiling level systems and the proposed supplemental systems to be provided for areas which contain obstructions. These systems should prevent fire spread that could involve both redundant shutdown trains. Therefore, at least one shutdown train should remain free from fire damage in the event of fire.

CONCLUSION Based on our evaluation, we conclude that, upon completion of the proposed i

modifications, the fire protection afforded by the ceiling level sprinklers and the proposed supplemental sprinkler systems will achieve an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2.b.

Therefore, the licensee's deviation request is granted.

. 12. FIRE DETECTORS AND FIRE SUPPRESSION SYSTEMS NOT PROVIDED FOR ALL PLANT AREAS CONTAINING SAFE SHUTDOWN EQUIPMENT DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2 which requires that fire detectors and automatic fire suppression systems be provided throughout areas containing redundant safe shutdown equipment which is separated by less than three-hour fire-rated construction.

DISCUSSION Within the auxiliary building, a number of rooms or portions of rooms do not have the required detection and/or suppression system.

The licensee's evaluation found that none of these rooms contain components or cabling for both redundant shutdown trains. The analysis indicates that for the rooms with rated walls of less than three hours, the fixed combustible loading will yield a fire severity that is less than one half the rating of the room enclosures.

In rooms without rated walls, the construction of the walls is of reinforced masonry block which is equivalent l

to at least 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />, but wall penetrations have not been provided with fire-rated doors, fire dampers, or qualified fire-rated seals. However, these rooms contain no appreciable amounts of in-situ combustibles.

Standpipe and hose stations and portable extinguishers are provided throughout the Auxiliary Building for use in these areas in the event of fire.

TVA justifies this deviation based on the low combustible loading and small size of the rooms, which thus do not pose a significant fire exposure hazard to redundant safe shutdown cables or equipment in the auxiliary building.

EVALUATION A number of rooms or portions of rooms within the auxiliary building are not provided with fire detection and/or automatic fire suppression systems as required by Appendix R,Section III.G.2.

The licensee analysis indicates that the combustible fuel load for these rooms is low, the rooms are of relatively small area and do not present a significant fire exposure hazard to redundant safe shutdown components and cabling. A fire within any of these rooms should be detected by the fire detection equipment in adjacent areas within sufficient time to pennit fire brigade response and fire extinguishment prior to damage to both shutdown trains.

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. CONCLUSION Based on our evaluation, we conclude that the fire protection features' provided for these areas afford an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2 and the licensee's deviation request is granted.

13. ONE HOUR RACEWAY FIRE BARRIERS DO NOT EXTEND THROUGHOUT THE FIRE AREA DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2 which requires redundant safe shutdown components to be separated from each other by one of the following methods:

Separation by a fire barrier having a three-hour rating.

l Separation by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards and provisions of fire detection and automatic fire suppression systems within the fire area.

Enclosure of one re6ndant shutdown train in a fire barrier having a one-hour rating v.o providing fire detection and automatic fire suppresion syscems within the fire area.

DISCUSSION Raceways containing redundant shutdown circuits in the auxiliary building that are not separated by a horizontal distance of 20 feet or more are enclosed in a one-hour fire-rated barrier until a 20-foot separation is attained. This is not in literal compliance with Appendix R,Section III.G.2 which requires the raceway fire barrier to extend throughout the fire area.

In the locations of the auxiliary building where redundant cables are protected by a one-hour fire-rated barrier until 20-foot separation is attained, there are no significant in-situ fire hazards present, except for cable insulation in the cable trays. Fuse and breaker coordination provides adequate protection to clear any electrical fault from the cables before its insulation reaches the auto-ignition temperature.

Therefore, an internally generated cable tray fire that could affect both redundant shutdown trains is not considered a credible event. An exposure fire at the floor represents the only significant fire hazard for the redundant cables. Sprinkler coverage is provided at the ceiling in the rooms where partial one-hour fire-rated barriers are installed. These sprinklers will release large quantities of water in well developed patterns at the ceiling during a fire. The cooling effect of this water will prevent the formation of a heat plume and will control room temperatures until the fire brigade can respond and extinguish the fire using the standpipe and hose stations and portable extinguishers provided through the auxiliary

. building. For areas where intervening cable trays are located between the unwrapped portions of the redundant circuits (separation greater than 20 feet), the licensee proposes to provide additional sprinklers.

The licensee's justification for this deviation is based on the position that the one-hour fire-rated barrier wrap for the cable raceways teminates within an area provided with automatic sprinkler protection which in conjunction with the 20 feet of separation between trains provides equivalent protection to that stipulated by Appendix R,Section III.G.2.b.

EVALUATION Redundant shutdown cable racewa i within the auxiliary building do not meet the technical provisions c Appendix R,Section III.G.2 because the one-hour fire barriers provide for the separation of one of the redundant raceways terminate within the Mme fire area in which the other raceways are located. The fire barriers,ce required to protect one redundant shutdown train through the entire ire area.

A number of raceways within the auxiliary building are enclosed within a one-hour fire-rated barrier to provide the required separation from adjacent raceways which contain cables for the redundant safe shutdown train. The fire barrier is provided for the raceway only until a 20 foot separation is attained. At this location, ceiling level sprinkler protection is provided. The licensee proposes to prc<ide additional sprinkler coverage for areas in which there is appreciable obstructions to the discharge from the ceiling level sprinklers. Also, additional sprinklers are to be provided for the areas where intervening cable trays are located between the unwrapped portions of the redundant circuits. The fire barriers provided for the redundant raceways, the existing ceiling level sprinkler system and installation of the proposed supplemental sprinklers should provide sufficient protection to assure that one shutdown train will remain free from fire damage in the event of a fire within the auxiliary building.

CONCLUSION Based on our evaluation, we conclude that upon completion of the proposed automatic sprinkler system modifications, the protection provided by the partial raceway fire barriers in conjunction with the automatic sprinkler systems will achieve an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2. Therefore, the licensee's deviation request is granted.

14. MANUAL OPERATION FOR CONTROL ROOM AIR HANDLING UNIT DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G which requires that one train of systems needed for hot standby must be maintained free from fire damage and operability

. of the hot standby systems must exist without making any repairs.

Removal of fuses for isoi6 tion and use of jumpers are considered repairs.

DISCUSSION Remote control cable 1PL45128 for the main control room air handling unit (MRC AHU) interacts with cables associated with MCR AHU A-A on elevation 714 of the auxiliary building. The MCR AHU B-B cable IPL45128 will be disabled in the event of a fire by lifting wires B21DT1, B21DTP, B21DG1, and B21DW in compartment 1D of the 480V shutdown board IB2-B, installing a jumper between tenninal blocks 26 and 27 on the compressor and by replacing necessary control fuses. The HVAC system (Train B) will then be operated using the local controls at the compressor. A causality procedure will be provided to address the wire lifts, jumper, and control fuse replacement.

The above wire lifts, jumper, and control fuse replacement will be necessary to achieve main control room (MCR) ventilation. Cable 1PL4512B is for remote control only. The wire lifts and jumper will only be required in the event the fire damage prevents the compressor from starting. Once the wire lift and jumper are accomplished, the compressor can be operated using existing manual controls located at the compressor.

Plant operating experience indicates that MCR temperatures will not exceed 104*F within a five-hcur time duration and no safety-related equipment should be damaged. The time required to complete the wire lifts, jumper, and control fuse replacement is approximately one hour. Adequate manpower is available to perfonn the required actions. The location where the postulated fire ndy cause loss of both MCR AHU A-A and B-B (auxiliary building elevation 714) is separated from the MCR AHU B-B compressor and associated local controls, which are located in the control building, by three-hour fire-rated construction. The 480V shutdown board room 182-B I

where the wire lifts will be performed is separated from the postulated fire location by li hour fire-rated construction.

In addition, automatic sprinklers, detection, standpipes, and portable extinguishars are provided for the above three locations.

EVALUATION The technical requirements of Appendix R,Section III.G are not met, in that in order to maintain ventilation of the control room, repairs may be required for the control room ventilation system in the event of fire, within the auxiliary building. These repairs consist of the use of wire lifts, jumper and control fuse replacement and require approximately one hour to accomplish. The licensee's analysis indicates that the control room temperature will not exceed 104*F within five hours after the loss of the control room ventilation system. This is sufficient time to permit necessary repairs to be accomplished prior to the need for control room ventilation. Furthennore, the fire protection features provided for the auxiliary building should reduce any major fire damage.

l CONCLUSION Based on our evaluation, we conclude that the repairs required to restore ventilation to the control room in the event of a fire within the auxiliary building can be accomplished within a reasonable period of time prior to damage to any safety-related equipment. Also, the fire protection features provided for the auxiliary building should eliminate any major fire damage to the cabling and components of the control room ventilation system.

These features provide an acceptable level of protection equivalent to that required by Appendix R,Section III.G.2 and the licensee's deviation request is granted.

15. INADEQUATE SEPARATION OF ERCW POWER CABLES DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.G.2.c which requires that one redundant train of components necessary for safe shutdown be enclosed by a one-hour rated fire barrier and that fire detectors and an automatic fire suppression system be installed in the fire area.

DISCUSSION On elevation 690 of the auxiliary building, power cables for both redundant divisions of the Essential Raw Cooling Water (ERCW) pumps and the ERCW pumping station transformers from the yard pump house are routed into a metal enclosure (pull box) mounted on the concrete wall approximately ten feet above the ficor.

Each voltage level and train is separated from each other within the pull box by metal partitions. Circuit protective devices will ensure that a fault on any of these circuits will be cleared before the insulation on the cables reach their auto-ignition temperature.

The pull box has been provided with a 11 hour1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> fire-rated coating of Pyrocrete on the outside of the box. Cables for one redundant train penetrate the box and run on elevation 690 while cables for the opposite redundant train are enclosed in a 11 hour1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> fire-rated barrier from che pull box to the elevation 690 ceiling.

Elevation 690 of the auxiliary building is provided with a pre-action sprinkler system actuated by cross-zoned ionization smoke detectors. Additional sprinklers are provided in the area around the pull box.

TVA's justification for this deviation is based on the position that appropriate fire protection has been provided for these circuits. Also, the fire protection for these circuits was reviewed by the NRC and determined to be appropriate and acceptable in the SER dated February 1980.

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. EVALUATION The ERCW power cables do not meet the separation requirements of Appendix R Section III.G.2.c in that the cables for one train which are in the same fire area as the redundant train are not enclosed within a one-hour fire-rated barrier and area fire detection and fixed fire suppression systems are not provided. These cables are located with a raceway pull box and are separated by metal partitions which have less than one-hour fire rating. A fire detector or suppression system is not provided within the box. However, the box has been coated with Pyrocrete to provide a 11 hour1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> fire-rated barrier. Therefore, an exposure fire outside the pull box should not damage the cables within the box prior to extinguishment by the area sprinkler system or by the plant brigade due to the coating on the box. The circuit protective devices for the cables within the box provide assurance that the circuit will be cleared prior ta the cables reaching their auto-ignition temperature. The protection provided should assure that one shutdown train will remain free of fire dmage.

CONCLUSION Based on our evaluation, we conclude that the fire protection features provided for the ERCW power cables will achieve an acceptable level of protection equivalent to that required by Appendix R Section III.G.2.c; therefore, the licensee's deviation request is granted.

16. FIRE RATING OF EQUIPMENT HATCH DEVIATION REQUEST TVA requested a deviation from the requirements of 10 CFR 50 Appendix R, Section III.G.2.c which requires that redundant components required for safe shutdown be separated from each other by a fire barrier having a rating of one-hour and that fire detectors and automatic suppression systems be installed in the area.

DISCUSSION The covered hatch that separates 480V reactor MOV board room 2A (elevation l

749) from 6900-V shutdown board room B (elevation 734) has been coated with Pyrocrete to provide a three-hour fire barrier between these two rooms. However, this design configuration has not been subjected to a hose stream test. The installation is similar to the configuration tested by Industrial Testing Laboratories, Inc., and approved for a three-hour fire rating. This installation makes the hatch an integral part of the elevation 734 ceiling. ASTM E119-83 does not require hose stream tests on columns, floor or ceiling assemblies. The NRC Information Notice 84-09 states that fire barriers installed to meet the requirements of Appendix R Section III.G.2 must have a fire rating based on testing conducted by a nationally recognized testing laboratory for the configuration used in the plant.

. Both the 480V reactor M0V board room 2A and the train B 690V shutdown board room are provided with pre-action sprinkler systems actuated by ~

cross-zoned ionization smoke detectors.

TVA's justification for this deviation is based on the position that the protection and separation is adequate for these two rooms and that a hose stream test is not required for the covered hatch that has been upgraded to a three-hour fire barrier.

EVALUATION The separation between the 480V reactor MOV board room 2A and the 6900V shutdown board room B does not meet the technical requirements of Appendix R Section III.G.2.c in that the fire rcted coating installed on the equipment hatch cover between these two rooms is based on a design that has not been subjected to a hose stream test. However, this coating is rated at three-hours in lieu of the required one-hour and both of these rooms are provided with automatic sprinkler protection. These features should assure that at least one train will remain free of fire damage in the event of fire.

CONCLUSION Based on our evaluation, we conclude that the fire protection features provided for the separation between the 480V reactor motor operated valve board room 2A and 6900V shutdown board room B will achieve an acceptable level of protection that is equivalent to that required by Appendix R Section III.G.2.c and the licensee's deviation request is granted.

17. ONE-INCH MINERAL WOOL BARRIERS IN LIEU OF ONE-HOUR FIRE Rt.TED BARRIERS I

l DEVIATION REQUEST A deviation was requested from Section III.G.2.c to the extent that it requires a one-hour fire rated barrier between redundant safe shutdown cables.

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DISCUSSION All safe shutdown circuits located within 20 feet of their redundant counterparts are routed through conduits wrapped in a 1-inch-thick Kaowool enclosure. The fuel load in the area consists of the charcoal filters in l

the auxiliary gas treatment system. This unit, which contains charcoal filters, has been provided with an internal fixed water spray system and l

the room area is covered by a preaction sprinkler system. The overall fuel load in the area is negligible.

l The safe shutdown components in this area consist of the aforementione/

cables.

l

. Existing fire protection consists of fire extinguishers, manual hose stations, an area-wide fire detection system, and partial automatic fire suppression system coverage.

EVALUATION The technical requirements of Section III.G.2 are not met because TVA has installed fire rated enclosures around the conduits that meet the acceptance criteria of ASTM E-119 for 40 minutes instead of I hour.

In the 1978 Babcock and Wilcox report, " Tests for Fire Protection for Complete Fire Engulfment of Cable Trays and Conduits Containing Grouped Electrical Conductors," a 1-inch-thick Kaowool blanket wrap on solid bottom cable trays provided 40 minutes' protection for the cable tray when heated in a natural gas-fired furnace according to the heating rate specified in ASTM E-119.

The Sequoyah installation is deemed to provide better protection than the 40-minute endurance rating of the Babcock & Wilcox test for the following reasons:

a.

Conduits are used in lieu of solid bottom cable trays; b.

The limited exposure to the conduit from the equipment located in the area is not equal to the direct flame impingement on the cable trays during the test; and c.

The light fuel load in the conduit-traveled area is not likely to produ'ce the 2.5 million Btu per hour of the test furnace.

The principal concern was that if a fire should occur in any location where this barrier is installed, the elevated temperature produced could damage the Kaowool barrier and the protected shutdown cables within it, prior to the fire being extinguished. However, this area is protected by a fire detection system which annunciates in the control room.

It is expected that the detectors would activate while the fire is in its l

formative stages, prior to significant heat and smoke generation.

The fire brigade would then be sununoned and would extinguish the fire using portable fire extinguishers or manual hose stations.

Pending arrival of the fire brigade, the smoke and hot gases from the fire would be dissipated up into the ceiling area and outward into adjoining locations.

If a significant temperature rise occurs, the sprinkler system would actuate to control the fire and cool the surrounding air temperatures.

l Therefore, the Kaowool barrier and the shutdown-related cables would not be subjected to the elevated temperatures which would cause them to fail.

1

\\ Before the sprinkler system is activated, the inherent fire resistance of the Kaowool barrior provides reasonable assurance that at least one shutdown division would remain free of fire damage pending eventual fire extinguishment.

CONCLUSION Based on the evaluation, it is concluded that the existing level of fire protection provides an equivalent level of fire protection to that achieved by compliance with the technical requirements of Section III.G.2.c.

Therefore, the licensee's deviation is acceptable.

18. SEPARATION REQUIREMENTS FOR SAFE SHUTDOWN CIRCUITS INSIDE CONTAINMENT DEVIATION REQUEST A deviation was requested from the technical requirements of Section III.G.2.d to the extent that redundant safe' shutdown cables in containment are not (1) separated by a horizontal distance of more than 20 feet free of intervening combustibles; (2) separated by a noncombustible radiant energy heat shield; or (3) protected by fire detection and automatic fire suppression systems.

DISCUSSION Inside the primary containment, all circuits needed for safe shutdown during a fire are routed in conduits. An oil collection system is in l

place for the reactor coolant pumps. A suppression and detection system has been provided -for the reactor coolant pumps for protection against the lube oil fire hazard potential. Also, cable trays in this area have oeen enclosed with non-fire rated barriers. Manual fire fighting equipment

• is available in the area.

EVALUATION The principal concern is that if a fire should occur within the containment, close-spaced redundant shutdown systems would be damaged prior to the arrival of the plant fire brigade and eventual fire extinguishment.

Because TVA has provided an oil collection system for the reactor coolant pumps, the most significant fire hazard within the primary containment l

has been mitigated. However, this feature has not resulted in the complete elimination of all fire hazards and possible ignition sources. Therefore.

l there is still a possibility that a fire may occur.

If a fire does occur in those locations within the primary containment where redundant shutdown cables are located, the only protection available is the conduits in which s

I the cables are located. A conduit has no inherent fire resistance although it is noncombustible. Since the cables inside a conduit are in contact with the conduit metal, any exterior temperature rise would be conducted

. directly to the cable with no significant time delay or thermal lag.

Hence, circuit shorts could be (and would be) expected to occur within, several minutes of direct fire exposure. This rapid time to damage occurrence prevents reliance on active fire protection measures since their initiation also takes more than several minutes.

CONCLUSION Based on the evaluation, it is concluded that the existing level of fire protection in the primary containment does not represent an equivalent level of fire protection to that achieved by compliance with Section III.G.2.d. Therefore, TVA's deviation is unacceptable.

By letter from Gridley to Youngblood dated March 19, 1986, TVA had with-drawn this request for an exception to the requirements of Section III.G of Appendix R for the annulus and containment areas. TVA plans to perform modifications to install additional sprinklers and detectors in the annulus areas of both units and minor fire barrier sealing inside primary containment for each unit in acccrdance with Section III.G.

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. III.J - EMERGENCY LIGHTING In TVA's October 1, 1981, letter, TVA states that fixed self-contained ~

lighting consisting of halogen cycle sealed beam units with 8-hour battery packs are provided at Sequoyah in areas that must be manned for safe cold shutdown and for access and egress to and from all fire areas in safety-related structures (TVA made a similar commitment in their October 23, 1974, letter).

In their October 1,1981, letter, TVA also stated that their commitment exceeds the requirements specified in Section III.J of Appendix R.

By letter dated March 5,1986, TVA revised their commitment for emergency lighting. Their revised commitment states that emergency lighting units with at least an 8-hour battery power supply shall be provided in all areas needed for operation of safe shutdown equipment and in access and egress routes thereto. TVA's revised commitment is identical to Section III.J of Appendix R to 10 CFR Part 50 and is therefore acceptable.

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I

. III.L - ALTERNATIVE AND DEDICATED SHUTDOWN CAPABILITY

1. PROCESS MONITORING FUNCTIONS FOR CONDENSATE STORAGE TANK LEVEL, REFUELING WATER STORAGE LEVEL AND WIDE RANGE STEAM GENERATOR INDICATION NOT PROVIDED WITHIN AUXILIARY CONTROL ROOM DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 1

Appendix R,Section III.L.2.d which requires the process monitoring function for alternative or dedicated shutdown to be capable of providing direct readings of the process variables necessary to perform and control a plant shutdown. NRC IE Information Notice No. 84-09 identified the instrumentation necessary for alternative or dedicated shutdown.

DISCUSSION The following process monitoring instrumentation has not been provided in the auxiliary control room (ACR):

(1) Condensate Storage Tank Level (CST)

Indication, (2) Refueling Water Storage Tank Level (RWST) Indication, (3)

Wide Range Steam Generator Level Indication.

TVA provides the following justification for the lack of this instrumentation:

a. The CST level indication is not considered essential in the ACR due to automatic switchover capability to the essential raw cooling water (ERCW) header. During shutdown procedures, automatic switchover of the auxiliary feedwater pump suction from the CST to the ERCW header will be available when control is es'tablished in the ACR.

l Plant procedures instructs personnel operating the turbine driven AFW pump to insure automatic switchover takes place when suction pressure decreases below a specified level (indicating low level in the CST) or manually switch suction for all AFW pumps to ERCW, if automatic switchover fails to occur.

b. The RWST level indication is not considered essential in the ACR due to the large inventory and small demand requirements. The RWST contains over ten times the inventory required for cold shutdown. This is primarily used as makeup for contraction due to cooldown over a period of hours.

Additionally, RWST level can be locally detennined at the tank, as necessary.

c. Narrow range steam generator level and AFW flow indication to each generator is provided in the ACR. This instrumentation provides input to l

the automatic controls utilized to maintain steam generator (SG) level I

during plant shutdown during a fire. Although wide range instrumentation l

is available in the main control room (MCR), no automatic control or safety system inputs are derived from this instrumentation. Using AFW flow indication, the operator is able to confinn adequate reactor coolant system (RCS) post trip steam generator inventory control should the level fall below the narrow range indication. TVA's analysis indicates that e ---

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narrow range level indication along with AFW flow indication, which provides primary indication of heat removal capability, is sufficient for use in safe shutdown procedures whenever the ACR is utilized. Additionally, the new emergency operating procedures developed by the Westinghouse Owner's Group do not require wide range SG level indication. The post-accident monitoring requirements of Regulatory Guide 1.97 utilize narrow range level indication and AFW flow for the determination of an adequate heat sink.

EVALUATION The instrumentation provided on the remote auxiliary shutdown panel does not meet the requirements of 10 CFR 50 Appendix R, Section III.L.2.d since instrumentation is not provided for condensate storage tank level, refueling water storage tank level and wide range steam generator indication.

TVA has developed plant procedures which requires the operators to verify that the feedwater pumps automatically align to the essential raw cooling water header upon pump operation from the auxiliary control room or to manually align the pumps ir the automatic alignment fails to occur and the pump suction pressure decreases below a specified level. The RWST level is available locally at the tank. Therefore, the tank level can be determined if needed. Wide range steam generator level indication is not required by the Westinghouse Owner's Group and is not provided on the auxiliary control panel. Regulatory Guide 1.97 utilizes narrow range level indication and auxiliary feedwater flow for detennination of an adequate heat sink. This instrumentation is provided in the auxiliary control room and is considered sufficient by TVA's analysis for use in a

safe shutdown procedures.

CONCLUSION Based on our evaluation, we conclude that the available process monitoring instrumentation will achieve an acceptable level of protection equivalent to that required by Appendix R Section III.L.2.d and the licensee's deviation request is approved.

2. AUXILIARY CONTROL ROOM - T-COLD INSTRUMENTATION DEVIATION REQUEST In their December 18, 1984, submittal, TVA requested a deviation from the technical requirements of 10 CFR 50 Appendix R Section III.L.2.d to the extent that the alternative or dedicated shutdown capability be capable of providing direct readings of process variables necessary to perform and control a plant cooldown.

. DISCUSSION The licensee has not provided T-cold instrumentation in the auxiliary control room. The licensee contends that T-sat can be used in lieu of T-cold to monitor natural circulation in the reactor and set the reactor cooldown rate by monitoring the saturation temperature corresponding to the secondary side steam generator pressure.

In addition, the licensee contends that an interruption in natural circulation in one loop can be detected by observation of an increased Delta-T between the hot leg temperature and T-sat in the other loops. The licensee justifies the acceptability of the deviation requested on the basis that T-sat in lieu of T-cold can be utilized to verify natural circulation conditions in the reactor coolant system and establish the reactor cooldown rate.

EVALUATION AND CONCLUSION The ifcensec has submitted additional information on this deviation by letters dated March 19 and May 2,1986. The staff currently is reviewing these submittals and will provide their evaluation and conclusion in future correspondence.

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I 1 III.0 - OIL COLLECTION SYSTEM FOR REACTOR COOLANT PUMP

1. NON-SEISMIC DRAIN PIPING FROM EACH REACTOR COOLANT POMP OIL COLLECTION' SYSTEM DEVIATION REQUEST TVA requested e deviation from the technical provisions of 10 CFR 50, Appendix R, Section III.0 which requires the oil collection system including the drain piping system to be designed, engineered, and installed such that failure will not lead to fire during nomal or design basis accident conditions and there is reasonable assurance that the system will withstand the Safe Shutdown Earthquake (SSE).

DISCUSSION The lubricating oil system for the reactor coolant pump motors and the collection system drainage tanks (auxiliary containment sumps) are all designed not to fail during a SSE and to remain functional following a seismic event. However, the drain piping between the oil collection basins from around the pumps to the drain collection tanks is designed to not fail and damage nuclear safety-related equipment during a SSE but is not designed to maintain its pressure boundary integrity following a SSE.

TVA's justification analysis indicates that random oil leaks are not assumed to occur simultaneously with a seismic event and justifies the deviation on the basis that the design of the lubricating system provides more than reasonable assurance that the system will not fail and cause a fire as a result o~f a seismic event.

EVALUATION The technical requirements of Appendix R,Section III.0 are not met in that the drain piping between the collection basin from around the pumps to the drainage tanks is not designed to maintain its position and pressure boundary integrity following a SSE. However, the motors for the reactor coolant pumps and the lubricating oil systems are designed with the i

capability for withstanding a SSE. Therefore, major oil leaks shculd not occur during a seismic event and random oil leaks during nomal plant operations should be safely collected by the collection system.

CONCLUSION Based on our evaluation, we conclude that the oil collection system for the reactor coolant pumps will achieve an acceptable level of protection equivalent to that required by Appendix R Section III.0; therefore, the licensee's deviation is granted.

O 2. INADEQUATE SIZE DRAIN TANK FOR OIL COLLECTION SYSTEM DEVIATION REQUEST TVA requested a deviation from the technical provisions of 10 CFR 50 Appendix R, Section III.0 which requires the drainage collection tank for the reactor coolant pump oil collection system to hold the entire contents from all of the reactor coolant pump lubricating oil systems within each reactor building.

DISCUSSION The lubricating oil system for the reactor coolant pump motors and the oil collection system drainage tanks (auxiliary reactor building sumps) are all designed not to fail during a SSE and to remain functional following a seismic event. Therefore, since the lubricating oil system for the reactor coolant ) ump motors should not be damaged during a seismic event, the drainage tanc for the oil collection system should only need to be required to hold the oil resulting from the largest spill from a single failure or random leak in lieu of the largest spill rupture from all of the reactor coolant pump motors within each containment.

TVA's justification analysis indicates that the largest postulated single lubricating system failure for one reactor coolant pump would be retained by the collection system and then drained into the auxiliary reactor building sump and embedded piping between the collection system and the drainage sump. The licensee justifies the deviation based on the seismic design of the reactor coolant pump motors and lubrication system which should limit the niaximum oil spill to the quantity of oil from a lubricating system rupture or failure from only a single pump motor. The drainage system and collection sump are of sufficient size to accomodate this spill.

EVALUATION The technical requirements of Appendix P Section III.0 are not met in that the capacity of the oil collection system drainage tank is insufficient to hold the entire lube oil capacity from potential pressurized and unpressurized leakage from all four reactor ccolant pump lube oil systems within each reactor building.

The largest single lubricating system failure should involve 240 gallons of oil from the upper bearing oil system for one reactor coolant pump.

This oil would be canht by the oil collection system and drained into the auxiliary reactor building sump which has a capacity of approximately 200 gallons. Additional storage capacity of 140 gallons would be available in the embedded piping systems between the collection systems and the sump. The total capacity of the sump and piping systems is approximatley 340 gallons. This is greater than the largest postulated oil spill.

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- Procedures have been issued which require the operator to pump down the sump in the event of a reactor coolant pump high/ low reservior alarm to assure adequate capacity is available within the sump for oil collection.

In the unlikely event that the sump is full of water, the licensee's analysis indicates that no more than 100 gallons of oil would backup through floor drains. This oil would not come into contact with hot piping or other ignition sources.

CONCLUSION Based on our evaluation, we conclude that the size of the oil collection system drainage tank should be of sufficient size to accommodate the largest potential oil leak from one reactor coolant pump. Since the pump motors and 1C:;ricating systems are designed to withstand a SSE, the failure of more than one lubricating system during a seismic event should not occur. Therefore, the oil collection systems provide an. acceptable level of protection equivalent to that required by Appendix R Section III.0 and the licensee's deviation request is granted.

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DISTRIBUTION:

-Docket File,,

NRC PDR Local PDR PDf4 Reading File (3)

BJYoungblood OELD EJordan BGrimes JPartlow TAlexion MDuncan ACRS (10) i

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