ML20212F379
| ML20212F379 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 12/31/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20210K151 | List: |
| References | |
| TAC-11079, TAC-11080, NUDOCS 8701090680 | |
| Download: ML20212F379 (10) | |
Text
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8
'g UNITED STATES
[
.g NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXEMPTIONS FROM APPENDIX R TO CFR PART 50-WISCONSIN ELECTRIC POWER COMPANY POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-266 AND 50-301
1.0 INTRODUCTION
By letter dated June 30, 1982, Wisconsin Electric Power Company (the licensee) submitted its response to 10 CFR Part 50 Appendix R.
This response contained a fire hazards analysis, which was also the foundation for the requested exemptions.
By draft safety evaluation dated January 14, 1983, the NRC denied all requested exemptions except for the control room and the hydrogen hazard fire protection analyses.
On March 22, 1983, an appeal meeting was held with the NRC and, as a result, the licensee submitted another document dated April 28, 1983.
This submittal revised certain exemption requests, withdrew unnecessary ones, proposed numerous plant modifications, and requested two new exemption requests pertaining to the auxiliary building. The licensee also submitted a final fire protection report in October 1983, which described the alternate safe shutdown features and requested two new exemptions relating to the auxiliary building. By letter dated July 3, 1985, the NRC approved exemption requests for Fire Zones 1, 2, 3, 7 and Fire Areas 5 and 8.
Exemption requests for Fire Zone 10 and portions of Fire Zone 2 and Fire Area 8 were determined not to be required. By letter dated August 21, 1985, the NRC denied the switchgear room (Fire Area 6) exemption request. The residual unevaluated exemption requests now include the two new ones in the licensee's April 28, 1983, submittal and the two exemption requests identified in the licensee's October 1983 final report.
This evaluation is based in part on the attached Technical Evaluation Report (TER) written by the NRR contractor Franklin Research Center (FRC). This TER has been reviewed by the staff and it is in agreement with the conclusions reached in the FRC TER.
Section III.G.1 of Appendix R requires fire protection features to be l
provided for structures, systems, and components important to safe sh1tdown, 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 station (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 />.
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.Section III.G.2 of Appendix R requires 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:
p a.
Separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a 3-hour rating. Structural steel forming a part of or supporting such fire barriers shall be protected to provide fire resistance equivalent to that required of the barrier; b.
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.
In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area; or c.
Enclosure of cables and equipment and associated non-safety circuits of one redundant 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.
If the above conditions are not met,Section III.G.3 requires that there be an alternative shutdown capability independent of the area, room, or zone of concern.
It also requires that fire detection and a fixed suppression system be installed in the area, room, or zone of concern.
These alternative requirements are not deemed to be equivalent; however, they provide an acceptable level of fire protection for those configurations in which they are approved by the staff.
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 conjunction with proposed modifications will provide a level of safety equivalent to the technical requirements of Section III.G of Appendix R.
In sunnary,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 l
configurations must meet the specific requirements of Section III.G or l
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 is 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 l
can be repaired within a reasonable time (minor repairs using components stored on the site).
Fire-retardant coatings are not used as fire barriers.
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. i Modifications required to meet Section III.G would not enhance fire
.l protection safety levels above that provided by either existing or-l 1
proposed alternatives.
ModificationsrequiredtMmeetSectionIII.Gwouldbedetrimental to overall facility safety.
j 2.0 SERVICE WATER PUMP ROOM FIRE ZONE, ELEVATION 7 FEET 0 INCH 2.1 Exemption Requested An exemption was requested from Section III.G.2.b to the extent that it f
requires 20 feet of separation without intervening combustibles between redundant safe shutdown equipment.
2.2 Discussion The service water pump room fire zone is a separate pump room within the circulating water pumphouse. This fire zone is constructed of 4
reinforced concrete and metal panel wall sections. The roof and one wall are connon components between the service water pump room and the circulating water pumphouse. The subject fire zone.is on elevation 7 i
feet, 0 inch. The upper section of the common and east walls are constructed of metal-grate; therefore, there is a free exchange of air between the service water pump room and the circulating water pumphouse. The entrance to the. service water pump is via a security door in the east wall. Within the service water pump room, there is a partial height, noncombustible wall that divides the six service water pumps into two sets of three. Currently, there is an access opening in this divider wall. The licensee will permanently seal this opening shut and install a new door into the second set of service water pumps. This new door will be located within the east wall, i
The.-Service water pump room is a rectangular shaped room with a ceiling i
height of 22 feet. The total room area is about 1,000 square feet.
There is essentially no fire loading on the floor proper and the primary fire load present is in the form of diesel fuel for the fire pump. This fuel oil is in a day tank located 32 feet away in the circulating water pumphouse and its piping is within the concrete floor. The day tank is 1
in a sump, which can contain the total diesel fuel volume of 250 gallons. There are no intervening combustibles located within the j
service water pump room that would serve a pathway between the two separated sets of three service water pumps. The total fire loading is 13,600 Btu per square foot. There are no concentrated fire loads or hazards within the service water pump room. This fire load translates into a fire severity of less than 12 minutes as represented by the ASTM E-119 time-temperature curve.
l The safe shutdown systems in the service water pump room include the six service water pumps for Units 1 and 2.
There are no exposed power or i
control cables. Also, there are no service water motor-operated valves i
required for safe shutdown. Any one of the six service water pumps is capable of providing the required service water flow for both units to achieve stable hot shutdown.
In addition, any two of the six pumps are capable of providing the required service water flow for both units to achieve cold shutdown.
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l The existing fire protection includes area wide smoke detection and an automatic wet pipe fire suppression system that has redundant connections to the fire main. Manual fire fighting capability is in the form of fire extinguishers and two 1 1/2-inch hose reel stations located adjacent to the entrance doors. Although 20 feet of separation without intervening combustibles is not available between redundant systems, the licensee has installed a partial height, noncombustible wall between the service water pumps such that they are divided into two sets of three.
This wall is liquid tight at the bottom.
2.3 Evalu} tion The fire protection in the service water pump room fire zone does not comply with the technical requirements of Section III.G.2.b of Appendix R because 20 feet of separation without intervening combustibles has not been provided betwen redundant safe shutdown equipment and cables related to the service water system.
The staff's principal concern with the level of fire protection in the service water pump room was that because of the lack of a 20-foot separation free of intervening combustibles, a fire of significant magnitude could develop and damage redundant shutdown-related systems.
However, the fire load in these locations is low.
If a fire were to occur, we expect it would develop slowly, with initially low heat release and slow room temperature rise. Because of the presence of the early warning fire detection systems, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control room. The fire brigade would then be dispatched and would extinguish the fire manually. Until the fire was put out, the noncombustible, partial height partition between the two sets of shutdown service water pumps and the automatic sprinkler system would provide sufficient passive and active fire protection to provide us with reasonable assurance that two of the total of six service water pumps wottld remain free of fire damage.
Another major factct that reduces the consequences of fire risk in this fire zone is that the six redundant safe shutdown system service water pumps are separated into two groups of three pumps with no intervening combustibles. This physical separation is accomplished by a partial height, noncombustible radiant energy heat shield that is installed in this zone. We find that the provision of 20 feet of separation with no intervening combustibles would not significantly increase the level of fire protection in the service water pump room fire zone.
2.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed fire protection measures in the service water pump room p'ruvides a level of fire protection equivalent to the technical requirements for Section III.G.2.b of Appendix R.
Therefore, the exemption request for the aforementioned zone should be granted.
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. EVATION -19 FEET, 3 INCHES RESIDUAL HEAT REMOVAL pVMp FI_RE ZONE, EL 3.0 Exemption Requested quirement of Section pression is not installed 3.1 An exemption was requested from the specif within the common residual heat removal Discussio_n rade at elevation -19 3.2 l
ilings, and The RHR pump room is a fire zone and is be ow gThis fi feet, 3 inches. walls having 3-foot-thick reinforced concrT ete.
rooms that open into a fifth room.Each RHR pump is in its own room.An ope Unit 2.
two sets of RHR pumps.
are for Unit 1 and two RHR pumps are for) discharges into the h
the upper elevation (-5 feet, 3 inc esThe wall of each R h
This access is at the top and, The common wall between each has a 4-foot-square openicg for access.
The ceiling height room.
hence, a short metal ladder is provided.RHR tions.
in this zone is 11 feet.
d the common middle room i
Each RHR pump room has about 88 square feet anThere a has 573 square feet.The only fire loading is in the form of the There are no h RHR pump.
Therefore, the total fire load is and 2 quarts of lubricating oil in eac zone.
fire intervening combustibles.Also, there are no concentrated f h ASTM E-119 Hence, the fire severity, as represented by t ethan 3 negligible.
time-temperature curve, would be lesshts of the four RHR pumps hazards.
h tdown of The safe shutdown equipment in this zone consOnly d for hot There are no power or control cables require in.two pairs.
the two units.
d for cold shutdown.
shutdown located in this fire zone.or repaired with detection system throughout installed The existing fire protection includes a fireThere is no hin the Manual fire fighting capability exists wittinguis the fire zone.
8 feet, 0 inch can be used auxiliary building in the form of fire exThe licens within the area.
The 1 1/2-inch hose station on elevation within the RHR fire zone.
modifications for this zone.
Evaluation does not comply with the 3.3 I G 2 b of Appendix R becaus The fire protection in the RHR pump fire zone technical requirements of Section II...
automatic fire suppression system has not tection in the RHR pump f an area wide automatic f fire zone.
Our principal concern with the level of fire pro t magnitude could develop and fire zone was that because of the absence oH suppression system, a fire of significan ld cevele If a fire were to occur, we expect th i
damage redundant RHR pumps.
is negligible.
11
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Because of the presence of the early warning fire detection systems, the fire would be detected in its incipient stages. The alarms from these detectors are annuniciated in the control room. The fire brigade would then be dispatched and would pxtinguish the fire manually. Until the fire was put out, the reinforced concrete barriers between the redundant RHR pumps would provide sufficient passive protection to provide reasonable assurance that one shutdown division of RHR pumps would remain free of fire damage. Another major factor that reduces the fire risk in these zones is that redundant RHR pumps are, in fact, separated by a solid, reinforced concrete wall that runs from floor to ceiling with no in-situ combustibles.
The staff finds that the installation of an automatic fire suppressior, system would not significantly increase the level of fire protection in the RHR pump fire zone.
3.4 Conclusion Based on the above evaluation, the staff concludes that the existing level of fire protection for the RHR pump fire zone provides a level of fire protection equivalent to the technical requirements for Section III.G.2.b of Appendix R.
Therefore, this exemption request for the aforementioned zone should be granted.
4.0 AUXILIARY BUILDING FIRE AREA, ELEVATIONS -19 FEET 3 INCHES: -5 FEET 3 INCHE5; 8 FEET; 26 FEET; AND 46 FEET 4.1 Exemption Requested An exemption was requested from the specific requirement of Section III.G.2.b to the extent that automatic fire suppression is not installed throughout the fire area.
4.2 Discussion The auxiliary building 1s composed of numerous zones and several small i
fire areas.
It can be viewed at having a north, south, and west wing with a central area. The elevations range from -19 feet 3 inches to 46 feet. The RHR pumps are located at the -19 feet 3 inch elevation; this is a separate exemption request (see Section 3.0 of this report). The other three elevation of -5 feet 3 inches, 8 feet, and 46, feet are constructed of reinforced concrete.
Penetration seals to other plant structures and construction joints are 3-hour fire rated. Doors exiting this area are 3-hour rated. These elevations are open to each other via j
an open stairwell and equipment hatch. The only safe shutdown equipment located herein are the RHR heat exchangers, which are in separate compartments; the 480-V motor control centers (MCCs) B33 and B43; and the component cooling water (CCW) heat exchangers. There are no safe shutdown equipment or cables required for hot shutdown located herein.
Also, safe shutdown cables are routed in conduit and there are no cable trays in the area.' Redundant trains of RHR cables are located on all elevations of this wing in configurations which are susceptible to l
damage from a single fire. However, the RHR system is not required for hot shutdown. A dedicated set of RHR pump cables will be provided for each unit. The fire loading in this wing ranges from 8,000 to 28,000 Btu per square foot. This translates into a fire severity of less than 21 minutes as represented by the ASTM E-119 time-temperature curve.
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Fire protection for the west wing consists of an area wide fire detection system, fire extinguishers, and two 1 1/2-inch hose reel j
stations located on the 8-foot elevation. The licensee verified that the lower elevations can be serviced by one of these hose stations.
The south wing at elevation 8 feet contains the auxiliary building exhaust fan rooms, heating ventilating and air conditioning (HVAC)
)
equipment room, laundry and chemical drain tank room, reactor coolant j
pump (RCP) seal water filter-area, Unit I chemical and volume ' control t
system (CVCS) charging pump rooms, and MCC 1-B32 room. The exhaust fan rooms contain no safe shutdown equipment and are a fire area because of the 2-and 3-hour fire rated enclosure components, which includes the doors. HVAC room 159 contains the exhaust fans and the Unit 1 red and blue channel instrument cables. The room enclosures are 2-and 3-hour fire rated components and the doorway openings have automatic water spray protection. The CVCS charging pump rooms each contain one pump.
The enclosures are 3-hour fire rated with the doorway openings protected by an automatic water spray system. Therefore, these pump rooms are separate fire areas, as is room 156. The absence of an automatic fire suppression system in room 156 was evaluated and granted by the NRC in an exemption requested dated July 3, 1985; similarly this is also true for i
the safety injection pump room. The CCW pumps are susceptible to damage from a single fire, but they are not required for hot shutdown. A spare pump and cables are being provided for the purpose of'a repair. The redundant divisions of charging pump cables are located here, but they too have been exempted from the Appendix R requirement for automatic fire suppression.
i-In general, construction throughout the south wing zones and areas is concrete. Penetrations and construction joints adjacent-to other plant structures are 3-hour fire rated seals. Doors exiting this structure are 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated.
Fire loadings do not exceed 24,000 Btu per square foot except for charcoal filters. This translates into a fire severity of 18 minutes, as represented by the ASTM E-119 time-temperature curve.
Fire protection for the south wing zones and areas within the auxiliary building consists of a fire detection system throughout, fire extinguishers, and hose reel stations. Also, several locations have wet l
pipe sprinkler system coverage.
The north wing has elevations 8 and 26 feet and is identical in terms of construction to the previously described portions of the south and west wings. That is, the walls, floor, and ceilings are either 3-hour fire rated or are 18-inch-thick concrete. The interior doorways to rooms have automatic water spray protection.
Penetrations and doors to adjacent plant structures are 3-hour fire rated.
i The north wing only contains safe shutdown equipment in the form of three charging pumps (one each in a concrete cubicle) and an MCC 2-B32 room. Also, redundant reactor coolant system (RCS) instrumentation for t
both units is at elevation 26 feet. Just as in the south wing for Unit j
1 charging pumps, the Unit 2 charging pump rooms do not have an automatic fire suppression system. However, by letter dated July 3, 1985, this aspect has already been granted an exemption from Appendix R,Section III.G.2.b.
. The fire loading in these zones and areas is less than 8,800 Btu per square foot, which translates into a fire severity of less than 7 minutes based on the ASTM E-119 time-temperature curve. The exception to this fire loading value isgthe charcoal filters and gas decay tanks, which have already been approved by the NRC in the August 1979 safety evaluation for not having a fire suppression system.
Fire protection for the north wing consists of an area wide fire detection system, fire extinguishers, partial coverage by wet pipe sprinkler systems, and hose stations.
4.3 Evaluation The fire protection in the auxiliary building does not comply with the technical requirements of Appendix R Section III.G.2.b because an automatic fire suppression system has not been installed throughout the area.
The staff's principal concern with the level of fire protection in the auxiliary building was that because of the absence of an area wide autonatic fire suppression system, a fire of significant magnitude could develop and damage redundant shutdown-related systems, e.g., the MCCs or CCWs. However, the fire load in these locations is low.
If a fire were to occur, we expect that it would develop slowly, with initially low heat release and slow room temperature rise.
Because of the presence of the early warning fire detection systems, the fire would be detected in its incipient stages. The alarms from these detectors are annunciated in the control room. The fire brigade would then be dispatched and I
would extinguish the fire. Until the fire was put out, either the 20 feet of horizontal separation or concrete fire barriers between the redundant shutdown-related systems would provide sufficient passive protection to provide reasonable assurance that one shutdown division would remain free of fire damage.
In the case of the redundant RHR cables subject to damage from a single fire, spare cables have been made available for a repair, which is allowed since the RHR system is not required for hot shutdown. The same applies to the CCW cables and pumps, and a spare CCW pump will also be provided and kept available in addition to the necessary cables.
Finally, in rooms 166,142,151, and 156, automatic sprinkler systems already exist. Also, areas such as the RHR pump room and six charging pump rooms have been previously evaluated and approved with respect to the absence of an automatic fire suppression system. The above areas represent over one half of the total auxiliary building area.
Therefore, the balance of areas represent non-critical areas containing no hot shutdown equipment and low fire loadings. The staff finds that the installation of additional automatic fire suppression systems would not significantly increase the level of fire protection in the auxiliary building.
4.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection combined with the proposed fire protection measures in the above fire zones provides a level of fire protection equivalent to the technical requirements of Section III.G.2.b of Appendix R.
Therefore, this exemption should be granted.
. 5.0 AUXILIARY BUILDING, ELEVATION 46 FEET 5.1 Exemption Requested l'
An exemption was requested from the specific requirement of Section III.G.2.a to the extent that the floor of the auxiliary building central j
area on elevation 46 feet is not a 3-hour fire rated barrier.
5.2 Discussion The construction and layout of the auxiliary building are presented in detail in the preceding exemption request (Section 4.0 of this report).
Essentially, the cuxiliary building is a single fire area composed of numerous zones and rooms. Some of the rooms area, in actuality, small fire areas. The total auxiliary building fire area was established by completely enveloping the areas of seismic construction with 3-hour fire rated barriers except for the central area floor on the 46-foot elevation. This elevation contains open stairways, doorways, and several hatches and, therefore, it is not a 3-hour fire rated barrier.
The majority of the elevation 46 feet level floor penetrations terminate on the 26-foot elevation, and alternate safe shutdown and charging pump cable reroutings to the 8-foot elevations will be provided. Therefore, hot shutdown would not be affected. Floor penetrations in the open floor span of elevation 46 feet are provided with 3-hour fire rated seals except for several hatches. These hatches, however, are kept closed with a concrete and steel plug. Although not fomally fire rated, these plugs would be highly fire resistive because of the mass and thickness of the hatch plug. Because these hatches were required for maintenance access, no combustibles, cable trays, or safe shutdown equipment are located nearby or within the intervening vertical spaces.
The open stairway is located 45 feet away from Unit 2 Division "A" charging pump cable routings. The CCW system heat exchangers are on elevation 46 feet, but they are in a separate fire rated compartment.
With the exception of the CCW heat exchangers, there are no safe shutdown equipment or cables located on the 46-foot elevation.
Fire protection exists in the form of a fire detection system, fire j
extinguishers, and 1 1/2-inch hose reel stations. The fire load is low (8,000 Btu per square foot), and this translates into a fire severity of less than 6 minutes as represented by the ASTM E-119 time-temperature curve.
5.3 Evaluation The fire protection in the auxiliary building, elevation 46 feet does not comply with the technical requirements of Section III.G.2.a of Appendix R because a complete 3-hour fire rated barrier has not been provided at the floor level within the central areas.
Our principal concern with the level of fire protection in the auxiliary building central floor area at elevation 46 feet was that because of the absence of a complete 3-hour fire rated floor, a fire of significant magnitude could develop and damage redundant safe shutdown cables at lower levels. However, there is only a low fire load on the floor area and there are no cables or equipment required for hot shutdown in and
. within the central area.
If a fire were to occur,' then we expect it would develop slowly, with initially a low heat release and slow area temperature rise.
Because of the presence of the early warning fire detection system, the fire would be detected in its incipient stages.
The alarms from these detectors are annunciated in the control room.
The fire brigade would then be dispatched and would extinguish the fire. Until the fire was put out, the existing floor with its hatch covers between the central floor area on elevation 46 feet and the location of safe shutdown equipment and cables on the lower elevations would provide sufficient passive protection to provide us with reasonable assurance that one division would remain free of fire damage. The staff finds that the provision of a 3-hour fire rated barrier for the floor level would not significantly increase the level of fire protection in this zone.
5.4 Conclusion Based on the above evaluation, the staff concludes that the existing fire protection for the auxiliary building central floor area at elevation 46 feet provides a level of fire protection equivalent to the technical requirements of Section III.G.2.a cf Appendix R.
Therefore, this exemption for the aforementioned zone should be granted.
Principal Contributor:
J. Stang Dated: December 31, 1986
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