ML20215E647
| ML20215E647 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 10/02/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215E571 | List: |
| References | |
| NUDOCS 8610150421 | |
| Download: ML20215E647 (15) | |
Text
A UNITED STATES
["
g NUCLEAR REGULATORY COTATAISSION g
j WASHINGTON, D. C. 20555
\\...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXEMPTION FROM APPENDIX R TO 10 CFR PART 50 YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION DOCKET NO.50-029
1.0 INTRODUCTION
By letter dated December 28, 1984, Yankee Atomic Electric Co. (the licensee) requested 13 exemptions from Section III.G of Appendix R to 10 CFR Part 50.
By letter dated April 30, 1985, the licensee withdrew exemption requests 1, 2, 3, and 6 and added exemption requests 14 through 17.
By letter dated November 7, 1985, the licensee withdrew exemption requests 4 (Main Control Room), 5 (Switchgear Room),11 (Vapor Container),
and 15, 16, and 17 (Vapor Container (additional)). Thus, seven exemption requests in four plant areas remained which are evaluated below.
The portions of Section III.G applicable to the licensee's exemption requests are presented below.
Section III.G.1 of Appendix R requires fire protection features to be provided for structures, systems, and components important to safe shutdown, capable of limiting fire damage so that:
a.
One train of systems necessary to achieve and maintain hot shutdown conditions from either the control room or emergency control stations (s) is free of fire damage; and b.
Systems necessary to achieve and maintain cold shutdown from either the control room or emergency control station (s) can be repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Section III.G.2 of Appendix R requires in part that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:
c.
Enclosure of cable and equipment and associated non-safety circuits of one redundar,t train in a fire barrier having a 1-hour rating.
In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.
%0$$
F
. Inside noninerted containments one of the fire protection means specified above or one of the following fire protection means shall be provided:
d.
Separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards.
i If the above conditions are not met,Section III.G.3 requires that there be an alternative shutdown capability independent of the fire area of concern.
It also requires that a fixed suppression system 4
be installed in the fire area of concern if it contains a large concentration of cable or other combustibles. These alternative requirements are not deemed to be equivalent; however, they provide equivalent protection for those configurations in which they are accepted.
Because it is not possible to predict the specific conditions under which fires may occur and propagate, the design-basis protective features rather than the design-basis fire are specified in the rule. Plant-specific features may require protection different from the measures specified in Section III.G.
In such a case, the licensee must demonstrate, by means of a detailed fire hazards analysis, that existing protection or existing protection in 4
conjunction with proposed modifications will provide a level of safety equivalent to the technical requirements of Section III.G of Appendix R.
In summary,Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and maintain safe shutdown are free of fire damage.
Either fire protection configurations must meet the specific requirements of Section III.G or an alternative fire protection configuration must be justified by a fire hazard analysis. Generally, the staff will accept an alternative fire protection configuration if:
The alternative ensures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control stations are free of fire damage.
The alternative ensures that fire damage to at least one train of equipment necessary to achieve cold shutdown is limited so that it can be repaired within a reasonable time (minor repairs using components stored on the site).
Fire-retardant coatings are not used as fire barriers.
Modifications required to meet Section III.G would not enhance fire protection safety levels above that provided by either existing or proposed alternatives.
Modifications required to meet Section III.G would be detrimental to overall facility safety.
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o 2.0 PRIMARY AUXILIARY BUILDING 2.1 Exemption Requested An exemption was requested from Section III.G.3 to the extent that it requires installation of fire detection and fixed fire suppression throughout an area requiring alternative shutdown capability.
2.2 Discussion The Primary Auxiliary Building (PAB) is an L-shaped building located south of the Vapor Container and the Safety Injection Accumulator Room and east of the Diesel Generator Building (DGB) and the Gas Storage Building. The PAB is approximately 131 feet long by 32 feet wide at the east end and 50 feet wide at the west end.
It is two stories high, except for the three-story section at the west end containing the primary and gravity drain tanks and Mechanical Equipment Room No. 3.
The DGB is described in Section 3.2.
The walls between the PAB and the DGB (inclu' ding the door) and the accumulator room wall that abuts the PAB provide a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier between the PAB and DGB.
Safe shutdown systems in the PAB include the two motor-driven emergency feedwater pumps; the three charging pumps and associated valves for each.
Both motor-driven emergency feedwater pumps are located on the west side of the PAB, along with the component cooling water pumps and several other systems. A steam-driven emergency feedwater pump which is located in the Turbine Building provides the redundant train for the motor-driven pumps. Each charging pump is located in a separate cubicle on the east side of the PAB. The safety injection pumps in the DGB provide a redundant shutdown train for the charging pumps.
Combustibles consist of electrical cable in conduit and lubricating oil in the various pumps. Most electrical cables are mineral-insulated, with the remainder in conduit (except inside Motor Control Center No. 4).
Lubricating oil in the feedwater pumps is limited to that in the bearings and the reservoir maintained in the oil cup. The charging pump gear drives contain between 7 and 17 gallons each, in a non-pressurized gear splash arrangement. The combustible loading is approximately 20,000 BTU l
per square foot, which produces an equivalent severity of 15 minutes on l
the ASTM E-119 time-temperature curve.
Intervening combustibles consist of the lubricating oil only, because cable is either mineral-insulated I
(noncombustible) or in conduit.
Each charging pump is located in a pit in l
its separate cubicle; therefore, oil will not flow between the pumps.
The combustible loading in the Safety Injection Accumulator Room is likewise estimated to be very low; in addition, the room is over 30 feet high.
1 l
l
. Fixed fire suppression systems are not provided in the PAB.
Fire detectors are provided only in locations with significant combustible loading. One detector is located above each charging pump cubicle; one is provided above Motor Control Center No. 4.
Fire hose and portable fire extinguishers are provided throughout the PAB.
2.3 Evaluation The fire protection in this area does not comply with the technical requirements of Section III.G.3 of Appendix R because fixed fire suppression and fire detection is not provided throughout the PAB.
The safety injection pumps, located in the DGB, provide alternate shutdown capability for the charging pumps, located in the PAB. The concern was that without fire detection and suppression in the PAB, a fire might spread to the DGB and affect the alternate shutdown capability.
Because of the light fuel load in adjacent portions of the PAB and DGB, the staff does not expect a fire of significant magnitude or duration to occur. The limited irtervening combustibles in the PAB do not provide a path for the spread of fire between redundant charging pumps because the cables are either mineral-insulated or routed in comiuit, and because the pumps are in pits in separate cubicles.
Should a fire occur in one of the charging pump cubicles, it should not spread because the pumps are in pits. A fire would be detected by installed fire detectors which will alert the plant fire brigade.
Upon arrival, the fire brigade will extinguish the fire. Should the fire continue, it will not spread to the safety injection pumps in the DGB because tha fire ratings of barriers and of doors between the PAB and DGB (including the Safety Injection Accumulator Room) excee the estimated fire severity.
NRR and contractor fire protection engineers visited the site to walk down l
the fire protection modifications already made by the licensee to comply with Appendix R and to review the above fire area where the exemption from Appendix R had been requested. Because of the light fuel load in the PAB there is reasonable assurance that a fire in the PAB will not result in the loss of safe shutdown capability. Therefore, the staff finds installation of fixed fire suppression and fire detection throughout the l
PAB would not significantly improve the level of fire protection.
l 2.4 Conclusion l
Based on the above evaluation, the staff concludes that the existing fire protection provides a level of protection equivalent to the technical requirements of Appendix R.
Therefore, the exemption is hereby granted.
l
. 3.0 DIESEL GENERATOR BUILDING 3.1 Exemption Requested An exemption was requested from Section III.G.2.c to the extent that it requires enclosure of cable and equipment and associated non-safety circuits of one redundant train in a fire barrier having a 1-hour rating.
3.2 Discussion The Diesel Generator Building (DGB) is an L-shaped building located south of the Vapor Container and attached to the PAB (described in Section 2.2).
Exterior walls of the DGB are 8-inch concrete block. The Post Incident Cooling System (PICS) Building is adjacent to the northeast corner of the DGB, and the Safety Injection Accumulator Room is adjacent to the east end. Access between the DGB and the PICS Building is through a 3-hour rated fire door.
The three diesel generator rooms in the DGB are separated from each other and from the rest of the DGB by 8-inch concrete block walls (estimated 3-hour fire resistance).
Doorways between diesel generator rooms are protected with 3-hour fire rated doors; doorways between the diesel generator rooms and the rest of the building are protected by li-hour fire rated doors. The south portion of the DGB is not subdivided except that below grade Manhole No. 3, which is located in the southeast portion of the DGB, is provided with a 1/2-inch thick steel plate at floor level and a 3/8-inch thick steel manhole cover approximately one foot below floor level.
Safe shutdown equipment in the DGB includes three diesel generators, the high and low pressure safety injection pumps (three of each), associated cables and switchgear including Containment Isolation System (CIS) Train A power and control cables, and CIS Train B power cables (which are routed through Manhole No. 3 to the PAB).
Dedicated shutdown capability is provided for the safe shutdown equipment in the DGB and Manhole No. 3 by the Safe Shutdown System (SSS) located in other plant areas, except for CIS Train B power cables in Manhole No. 3 (CIS Train A is in the DGB).
Combustible materials in the DGB include cables inside Manhole No. 3, emergency switchgear and motor control centers, cables in trays in the PICS Building, lubricating oil in the bearings and bearing cup of the six safety injection pumps, and diesel fuel oil in piping in the south portion of the DGB. This latter piping is routed only in front of the diesel generator rooms and is provided with a splash shield which directs diesel fuel oil spillage towards the wall adjacent to the diesel generator rooms.
j The floor in front of this wall is provided with a 4-inch curb and a drain to an oil collection tank outside the building. The flow in this piping is gravity-fed. The combustible loaaing is approximately 20,000 BTU per square foot, which produces an equivalent severity of 15 minutes on the ASTM E-119 time-temperature curve.
Automatic fire detectors are installed throughout the DGB, including Manhole No. 3.
A manually-actuated sprinkler system is installed in each diesel generator room. A total flooding, automatic carbon dioxide fire extinguishing system is installed in Manhole No. 3.
Portable fire extinguishers and hose stations are located in the DGB and adjacent areas.
3.3 Evaluation The fire protection in the DGB does not comply with the technical requirements of Section III.G.2.c of Appendix R because associated non-safety circuits of one redundant train have not been enclosed in a fire barrier having a 1-hour fire rating.
A concern existed in that the lack of 1-hour fire rated barrier between Manhole No. 3 and the remainder of the DGB would provide a path for the spread of fire between associated circuits. The CIS is needed to isolate the solenoid-controlled air-operated valve in the bleed line. The concern was that a fire affecting both trains of the CIS might cause this valve to inadvertently reopen.
The diesel generator rooms are separated from the rest of the DGB by rated fire barriers, and are provided with automatic detection and manual fixed fire suppression systems. The fire detection systems would alert the plant fire brigade to a fire in one of these rooms.
Upon arrival, the fire brigade will extinguish the fire. Should the fire continue, it is not expected to spread beyond the fire-rated barriers of the diesel generator room in which it starts.
In the unlikely event that it does spread into the DGB, the CIS Train B power cables in Manhole No. 3 should be adequately protected by their location and by the barriers between the manhole and the room. Because of the light fuel load in the south portion of the DGB, the staff does not expect a fire of significant duration or magnitude to occur. The generally limited combustible contents of this zone do not provide a path for the spread of fire to or from Manhole No.
3; there are no intervening combustibles.
Should a fire start outside Manhole No. 3, it will be detected by the installed fire detectors which will alert the plant fire brigade.
Upon arrival, the fire brigade will extinguish the fire.
Should the fire continue, it will not spread to Manhole No. 3 because of the latter's location below the fire and because the two steel plates separated by over one foot provide an effective fire barrier in this situation.
Diesel fuel oil will not spread to the manhole because a spill will be confined by the splash shield and curb.
Should a fire start in Manhole No. 3, it will be detected by installed
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-7.
4 fire detectors which will alert the plant fire brigade and actuate the.
. total flooding carbon dioxide extinguishing system.
If the extinguishing system fails to operate properly, the fire brigade will-extinguish the 4
i fire. The fire is not expected to continue because of the limited combustible loading in the manhole and the_ ease with which a fire in such a confined space can be extinguished.
Dedicated shutdown capability is provided in the event of a fire in the DGB or in Manhole No. 3.
The associated circuit valve of concern requires i
air to reopen;.thus removal of the supply of air is a backup to the redundant trains of CIS. One of the immediate operator actions as part of using the SSS is to bleed off the air system in the Turbine Building.
This would be accomplished within 30 minutes. The staff believes at least 30 minutes would be available to complete this action, considering the fire detection and suppression capabilities in the DGB and in Manhole No.
3 as discussed abeve.
hRR and contractor fire protection engineers visited the site to walk down the fire protection modifications alrehdy made by the licensee to comply with Appendix R ar.d to review the above fire area where the exemption from Appendix R had been requested. Despite the presence cf a non-standard fire barrier between Manhole No. 3 and the remairder of the DGB, a fire in either location will not result in the loss of safe shutdown capability. Therefore, the staff finds that providing a 1-hour rated fire barrier over the access cover to Manhole No. 3 would not.
significantly increase the level of fire protection in this fire area.
3.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection provides a level of protection equivalent to the technical requirements of Appendix R.
Therefore, the exemption is hereby granted.
)
4.0 VAPOR CONTAINER 1
4.1 Exemptions Requested i
Exemptions were requested from Section III.G.2.d to the extent that it requires the separation of cables and equiprnent and associated non-safety l
circuits of redundant trains in containment by a horizontal distance of more than 20 feet free of intervening combustibles for fire hazards.
i i
Exemptions were requested for:
1.
The separation between the electrical blisters containing the power cables to the pressurizer solenoid-operated relief valve PR-SOV-90 and its motor-operated block valve PR-MOV-512.
2.
The separation between the electrical cables and the actuators for valves PR-S0V-90 and PR-M0V-512 in the pressurizer cubicle.
- 3. ' The separation between the electrical cables and transmitters for both pressurizer level instrumentation channels in the pressurizer cubicle.
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4.2 Discussion The Vapor Container is a steel spherical shell,125 feet in diameter, with a minimum wall thickness of 7/8 inches.
The containment structure surrounds the reactor vessel, steam generators, and associated equipment, and encloses all pressurized parts of the Main Coolant System.
It is a freestanding structure which abuts no other building and is connected by a concrete pipe tunnel to the PAB and by the spent fuel chute to the Spent Fuel Building. The internal concrete structure consists of two concentric cylinders of reinforced concrete.
These cylinders are tied together with six reinforced concrete radial walls so located as to provide an isolation compartment for each main coolant loop, for the pressurizer, and for two access ways from the equipment hatch into the structure. The compartment radial concrete walls have several ports to limit the differential pressure across the concrete walls. The inner concrete wall serves as the support for the reactor vessel, and water-filled neutron shield tank surrounding the reactor vessel, and as a shield tank cavity above the vessel. The shield tank cavity is lined with stainless steel. The personnel access opening is at the charging floor level just above the containment equator. The opening consists of a tubular shell penetration with 6-to 8-foot head room and with a steel plate door at each end, one inside and one outside the containment. A 13-foct, 111-inch ID equipment access opening is located in the lower part of the containment for handling large items or equipment. The opening is provided with a flanged, bolted, and gasketed cover which is removed from within by the overhead polar crane.
i Safe shutdown equipment requiring exemptions includes two redundant pressurizer level instrumentation channels and the pressurizer power operated relief valve and its block valve and their associated cables and instruments.
The power operated relief valve (PORV), PR-S0V-90, is normally closed.
i It is actuated by a 120 V de solenoid. A hot short to the power cable to this solenoid could cause the valve to open. The PORY block valve, PR-MOV-512, is in the same piping as PR-50V-90.
It would be manually closed to isolate the PORV line in the case where PR-50V-90 fails open.
It should also be noted that removing power from the solenoid for PR-S0V-90 would result in closure of the valve. This would require the hot short to clear.
If PR-SOV-90 were to inadvertently open and the power cable to PR-MOV-512 were damaged, the resultant loss-of-coolant would be considered a small LOCA. A fire in the Vapor Container would not prevent the successful operation of the Emergency Core Cooling System f
which would be required to mitigate this occurrence.
The power cables to PR-S0V-90 and PR-MOV-512 enter the Vapor Container through blisters. The cables to these two valves enter containment through separate blisters separated by a horizontal distance of approximately 12 feet. The 12-foot horizontal area between these two l
blisters is completely empty.
l Once these two conduits leave the blisters, they are routed in towards the biological shield wall that forms the outer barrier of the loop compartments. Here the conduits travel in opposite directions around the i'
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outside of the biological shield wall to just outside of the pressurizer cubicle. They never come closer than the 12 feet at the blisters. There are no intervening combustibles.
The 20-foot horizontal separation criteria was maintained until the conduits joined together outside of the pressurizer cubicle, where they entered the same junction box. The licensee has since rerouted the conduit containing the PR-50V-90 power cable from this junction box to another point where the conduit penetrates the 2-foot thick reinforced concrete biological shield wall. Once inside the biological shield wall, this conduit is then routed over to the pressurizer cubicle. Therefore, the 20-foot separation distance is maintained until the conduit approaches the pressurizer cubicle.
Inside the top of the pressurizer cubicle, the two valves are in the same pipe line where 20-foot separation is not possible.
Inside the pressurizer cubicle, the conduit.
for PR-S0V-90 is routed to maintain the maximum separation possible.
Two channels of pressurizer level indication are provided.
If both channels of level indication were damaged by a single fire, the operators would control primary water addition based on primary pressure indication. Multiple channels of primary pressure indication are available, and would not be affected by a fire in the pressurizer cubicle.
The pressurizer level transmitters (PR-LT-705 and PR-LT-8) and cables are separated by approximately 4 feet in the bottom of the pressurizer cubicle.
The conduit routing provides up to 10 feet of separation inside this area.
The lower section of the pressurizer is sectioned off from the main coolant loop areas with 18-inch reinforced concrete walls.
The area is approximately 8 feet by 16 feet by 12 feet high. The only combustible materials in this area are the signal cables to each of these level transmitters, and the power cables to the pressurizer motor-operated drain valve. All of this cable is in conduit and, therefore, is not considered to be an intervening combustible, with the exception of the last few feet at the transmitters and motor operator. This area is only accessible from a 40-foot ladder from the top of the pressurizer cubicle or a 10-foot ladder from the bottom of the loop area. Thus, transient combustible materials are not likely to be brought into this area.
Combustible contents in the Vapor Container include control rod drive and position indication cables in a cable tray and routed from the top of the reactor head up and out of the reactor cavity onto the charging floor.
The combustible loading in the Vapor Container is approximately 20,000 BTU per square foot, which produces an equivalent severity of 15 minutes on the ASTM E-119 time-temperature curve.
Intervening combustibles are l
limited to the control rod drive and position indication cables in trays.
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A line-type detector is routed in the previously mentioned cable tray; another monitors the entry platform near the personnel access hatch. One fire hose and portable fire extinguishers are available in Vapor Container.
, 4.3 Evaluation The fire protection in the Vapor Container does not comply with the technical requirements of Section III.G.2.d of Appendix R because cables and equipment and associated non-safety circuits of redundant trains in containment are not separated by a horizontal distance of more than 20 feet free of intervening combustibles or fire hazards.
l A concern existed in that the lack of 20 feet of separation free of intervening combustibles between redundant circuits of the pressurizer l
valves and of the pressurizer level transmitters could provide a path for l
the spread of fire which could result in a loss of safe shutdown capability.
Because of the light combustible load in the Vapor Container, the staff does not expect a fire of significant duration or magnitude to occur.
The only significant intervening combustibles are the control rod drive and position indication cables which are routed in a cable tray from the top of the reactor head up and out of the reactor cavity onto the charging floor. This cable tray runs above the neutron source range detector signal cables and is not near any other safe shutdown system of concern. Should a fire occur in the cable tray, it will be detected by the installed linear thermal detector which will alert the plant fire brigade. Upon arrival, the fire brigade will extinguish the fire.
In the staff's judgment, at no time will redundant safe shutdown systems be damaged by this fire.
Should a fire occur elsewhere in the Vapor Container, it is not expected to cause any damage to the redundant safe shutdown systems because of the light combustible load in their locations. The cables are run in conduit or are mineral-insulated and, therefore, present an insignificant fire hazard to their redundant counterparts. Horizontal separation distances between redundant cables are generally ten feet or more, and instrumentation is separated by at least four feet.
NRR and contractor fire protection engineers visited the site to review the existing fire protection features and the modifications implemented by the licensee to comply with Appendix R.
In spite of the separation distances of as little as four feet, a fire in any location in the Vapor Container will not result in the loss of safe shutdown capability because of the absence of intervening combustibles. Therefore, the staff finds that providing a 20-foot separation free of intervening combustibles would not significantly improve the level of fire protection in the Vapor Container.
4.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection, combined with the modifications made by the licensee, provides a level of fire protection equivalent to the technical requirements of Appendix R.
Therefore, the exemption is hereby granted.
- 5.0 TURBINE BUILDING 5.1 Exemption Requested An exemption was requested from Section III.G.3 to the extent that it requires the installation of fire detection and fixed fire suppression systems in an area for which an alternative or dedicated shutdcwn capability is provided.
5.2 Discussion The Turbine Building is a rectangular structure with three operating levels.
It abuts the Service Building on the east wall and an office en the northwest corner. The ground level encompasses an area approximately 160 feet long by 115 feet wide and includes the Heating Boiler Room, Lube Oil Room and Water Treatment Room. The mezzanine level is comprised of the enclosed Switchgear Room, the Ventilating Fan Room and an open area approximately 160 feet long by 80 feet wide. The operating floor level consists of the enclosed Control Room and an open area approximately 160 feet long by 80 feet wide. The outside walls below the mezzanine level are generally constructed of 8-inch concrete block; however, 32 feet of the west wall, south portion, is constructed of 12-inch poured concrete and most of the south wall facing the Vapor Container is constructed of 4 feet of reinforced concrete.
The outside walls above the mezzanine level are generally constructed of insulated metal panels. The west end, south portion, is constructed of 12-inch poured concrete. The insulated metal panels at the west end have a 2-inch thick layer of plasterboard which has a fire resistance rating of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
Personnel access to the ground floor is through 2 nonrated doors from the office building; a nonrated door on the north wall; a li-hour rated door on the west hall; a li-hour rated door on the west wall; a li-hour rated door from the outside leading into the southwest stairwell; a hallway from the Service Building; a 3-hour rated door from the Heating Boiler Room; and nonrated double doors from the Water Treatment Room. There are also 4 nonrated rolling steel doors for equipment access that are located on the north, west and east walls.
At the mezzanine level, a nonrated door opens onto the Water Treatment Room roof. At the operating floor level, a nonrated door opens onto the Heating Boiler Room roof. There are 3 open stairways at widely separated locations and an enclosed stairway at the southwest corner which opens into the Switchgear Room and the Control Room. There are several areas which are open from the ground floor to the operating level for crane access.
In addition, there is an enclosed elevator near the Control Room.
Safe shutdown systems in the Turbine Building include power, control, and instrument indication for the emergency power system, charging and emergency feedwater systems, and secondary systems.
Portions of these and other safe shutdown systems are also located in the Main Control Room, Switchgear Roon, and Cable Spreading Room.
No safe shutdowr, systems are located in the Water Treatment Room or on the operating level of the Turbine Building.
The operating floor of the Turbine Building also contains limited quantities of combustible material. The Main Control Room charcoal filter is enclosed in the filter housing with detection and suppression.
The small prefabricated office building contains combustible material,
-but-the building has'a separate fire detection system.
The main source of combustibles is the turbine and generator oil systems which are
. protected by sprinkler systems.
The oil from a break in this piping would drain.to lower levels of the building rather than collect on the turbine decks.
Oil pressure in these systems is usually less than 30 psig and is monitored in the Main Control Room so that any major loss of oil would generate alarms in the Main Control Room.
The Water Treatment Room has a light combustible loading.
The main combustible materials here are electrical cable.
Cable not in conduit is grouped only in Station MCC-3 and the water treatrrent distribution cabinet.
The lube oil reservoir is protected by an automatic foam system and is surrounded by a metal berm, and the seal oil unit and main transformer oil coolers are protected by an automatic deluge system.
The ground and mezzanine levels of the Turbine Building, including the lubricating oil storage room, are protected by automatic sprinkler systems.
The Water Treatment Room and operating level of the Turbine Building are not protected by fire detection or suppression systems, except that the office on the operating level is protected by fire detectors and the Main Control Room emergency air circulation system filter is protected by a manually activated deluge system.
Fire hose stations and portable fire extinguishers are available in the Turbine Building and in adjacent areas.
Dedicated shutdown capability is provided outside of the Turbine Building for a fire in the Turbine Building.
5.3 Evaluation The fire protection in the Turbine Building does not comply with the technical requirements of Section III.G.3 of Appendix R because a fixed fire suppression system is not installed in an area for which dedicated l
shutdown capability is provided.
A concern existed in which the lack of fire detection and fixed fire suppression systems in the Water Treatment Room'and on the operating level of the Turbine Building could permit a fire to cause the loss of safe shutdown capability.
1 The Water Treatment Room has a light combustible load and is separated from the rest of the Turbine Building by a minimum 8-inch concrete block i
wall and nonrated doors.
In addition, there is no safe shutdown equipment in this room.
Because of the light fuel load here, the staff does not expect a fire of significant duration or magnitude to occur.
Should a fire occur, it will be detected by plant personnel or by fire detectors or waterflow devices in adjacent areas, which will alert the plant fire brigade.
Upon arrival, the fire brigade will extinguish the fire.
Should the fire continue, it will not cause the loss of safe shutdown capability because dedicated shutdown capability is provided independent of the Turbine Building.
Because of the light fuel load on the operating level of the Turbine Building, the staff does not expect a fire of significant duration or magnitude to occur there.
Should a fire occur, it will be detected by operating equipment monitors which will alert the plant fire brigade.
Upon arrival, the fire brigade will extinguish the fire.
Should a fire continue, it will not cause the loss of safe shutdown capability because there is none on this level.
The fire is
not expected to affect the' Main Control Room because it is separated from the operating level by concrete walls and metal doors.
NRR and contractor fire protection engineers visited.the site.to walk down the fire protection modifications already made by the licensee to
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. comply with Appendix R and to review the Water Treatment Room and operating level of the Turbine building where the-exemptions from Appendix R had been request (d.
Despite the lack of fire detection and fixed fire i
suppression systems in these locations, a fire will not result in the loss of safe shutdown capability.
Therefore, the staff finds that providing fire detection and fixed fire suppression systems in these locations would not significantly increase.the level of fire protection.
5.4 Conclusion Based on the above evaluation,-the staff concludes that the existing fire protection provides a. level of protection equivalent to the technical j
requirenents of Appendix R.
Therefore, the exemption is hereby granted.
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6.0 DIESEL GENERATOR BUILDING I
6.1 he9ption Requested
[
An exemption was requested from the Section III.G.3 to the extent that it requires installation of a fixed fire suppression system in an area,
. room, or zone for which an alternative or dedicated shutdown system is 4
provided.
6.0 Discussion The Diesel Generator Building (DGB) is described in Section 3.2.
g Dedicated shutdown capability is provided outside of the DGB for a fire I
in the DGB.
i i-6.3 Evaluation The fire protection in the DGB does not comply with the technical requirements of Section III.G.3 of Appendix R because a fixed fire j
suppression system is'not installed in an area for which dedicated j
shutdown capability is provided.
A concern existed in that the lack of a fixed fire suppression system in the DGB could permit a fire to cause the loss of safe shutdown capability.
The diesel generator rooms are separated from the rest of the DGB by i
rated fire barriers, and are provided with automatic detection and manual I
fixed fire suppression systems. The fire detection systems would alert i
the plant fire brigade to a fire in one of these rooms.
Upon arrival, l
the fire brigade will extinguish the fire.
Should the fire continue, it is not expected to spread beyond the fire-rated barriers of the diesel
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generator room in which it starts.
In the unlikely event that it does spread, the CIS Train B power cables in Manhole No. 3 should be adequately protected by their location and by the barriers between the manhole and the room as discussed in Section 3.3 above.
Because of the light fuel load in the south portion of the DGB, we do not expect a fire of significant duration or magnitude to occur. The generally limited combustible contents of this zone do not provide a path for the spread of fire to or from Manhole No. 3; there are no intervening combustibles.
Should a fire start outside Manhole No. 3, it will be detected by the installed fire detectors which will alert the plant fire brigade. Upon arrival, the fire brigade will extinguish the fire. Should the fire continue, it will not spread to Manhole No. 3 because of the latter's location below the fire and because the two steel plates separated by over one foot provide an effective fire barrier in this situation.
Diesel fuel will not spread to the manhole because a spill will be confined by the splash shield and curb.
Should a fire start in Manhole No. 3, it will be detected by installed fire detectors which will alert the plant fire brigade and actuate the total flooding carbon dioxide extinguishing systen.
In the unlikely event that the extinguishing system fails to extinguish the fire, the fire brigade will complete the task. The fire is not expected to continue, because of the limited combustible loading in the manhole and the ease with which a fire in such a confined space can be extinguished, as described in Section 3.3 of this report.
NRR and contractor fire protection engineers visited the site to walk down the fire protection modifications already made by the licensee to comply with Appendix R and to review the above fire area where the exemption from Appendix R had been requested. Despite the lack of a fixed fire suppression system in the south portion of the DGB; a fire in this building will not result in the loss of safe shutdown capability.
Therefore, the staff finds that providing a fixed fire suppression system l
would not significantly increase the level of fire protection in this fire area.
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6.4 Conclusion
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Based on the above evaluation, the staff concludes that the. existing fire protection provides a level of protection equivalent to the technical i
requirements of Appendix R.
Therefore, the exemption is hereby granted.
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. 7.0 ACKNOWLEDGEMENT This Safety Evaluation has been prepared by'J. Stang, J. Clifford, and E. McKenna.
Date:
OCT 0 21986 9
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.y DISTRIBUTION:
%Ni NRC PDR Local PDR TNovak Glear EMcKenna PShuttleworth OGC-Bethesda EJordan BGrimes JPartlow ACRS (10)
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